Durability Of Velocity Aerohead Rims In 20/24 Hole Drillings.
Steve Sr.
I am considering rebuilding a set of wheels that had Alex 20/24 hole
rims. They went about 5K miles before the spokes started to pull
thorough the rims.
I am considering using these hubs and Velocity Aerohead and Aerohead
O/C rims but am wondering about the durability because of my previous
experience with the Alex rims.
I currently have a set of these Velocity rims but in 32 hole
configuration that have been flawless for the past 10K miles.
BTW, I only weigh about 160 pounds.
Thanks,
Steve
AMuzi
20/24 is in the 'not enough spokes' range generally but
given the hubs, yes, Aeroheads are your best choice in a
light clincher rim. 110Kg, even and round for best results.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
James
I weigh about the same, but weight is not the only concern. What
condition are the roads like where you ride? Are you gentle on the
wheels? Do you lift (bunny hop) the bike over rough spots, like
railway crossings and pot holes?
JS.
Ed
Why not the velocity A23 on the front? It weighs 1 gram more. But
"New for 2010! The A23 rim is based off our proven Aerohead race
rim. With a wider footprint, the A23 allows for a more aerodynamic
rim/tire combination when paired with a 23c tire. The tire profile
mimics the characteristics of a tubular, gaining increased control and
lower rolling resistance.."
Jay Beattie
>
> - Show quoted text -
Did they beef up the Aerohead -- it shows on the website as 425g, but
I remember it at closer to 400g. Peter White has it at 405g.
http://www.peterwhitecycles.com/velocity.asp
I think my next set of commuter/snow wheels will be the Synergy and
Synergy OC. -- Jay Beattie.
James
> On Nov 4, 4:59 pm, Ed <efont...@gmail.com> wrote:
>
>
>
> > On Nov 4, 6:37 pm, Steve Sr. <Nos...@nospam.com> wrote:
>
> > > Hello,
>
> > > I am considering rebuilding a set of wheels that had Alex 20/24 hole
> > > rims. They went about 5K miles before the spokes started to pull
> > > thorough the rims.
>
> > > I am considering using these hubs and Velocity Aerohead and Aerohead
> > > O/C rims but am wondering about the durability because of my previous
> > > experience with the Alex rims.
>
> > > I currently have a set of these Velocity rims but in 32 hole
> > > configuration that have been flawless for the past 10K miles.
>
> > > BTW, I only weigh about 160 pounds.
>
> > > Thanks,
>
> > > Steve
>
> > Why not the velocity A23 on the front? It weighs 1 gram more. But
>
> > "New for 2010! The A23 rim is based off our proven Aerohead race
> > rim. With a wider footprint, the A23 allows for a more aerodynamic
> > rim/tire combination when paired with a 23c tire. The tire profile
> > mimics the characteristics of a tubular, gaining increased control and
> > lower rolling resistance.."
>
>
> > - Show quoted text -
>
> Did they beef up the Aerohead -- it shows on the website as 425g, but
>
> I think my next set of commuter/snow wheels will be the Synergy and
> Synergy OC. -- Jay Beattie.
Fulcrum Racing series are fairly well regarded and from casual
observation and feedback from cycle shop employees, appear to be quite
robust and light.
JS.
James Jordan
18/24 combination.
Great wheels if you consider them race day only. I normally use them
for Criterium racing and longer/hillier sportifs.
I have had a couple of problems though, usted the rear rim hitting a
pothole and have just recently replaced the front due to cracking
around the nipples.
Considering the front was 2 years old and had not even needed a truing
during this time leads me to think I hit something but did not notice
it at the time.
James
Jobst Brandt
Why are you not riding 36-spoke wheels that would last many times
longer and not fail from local overload at the spoke holes? I think
you are afflicted with the "fewer spokes are faster" syndrome. In
that event, I'm surprised you aren't using CF rims, spokes, and
hubs... that fail even faster than wheels with low spoke-count metal
rims.
Jobst Brandt
Steve Freides
+1
I remember using a relatively light, single bike wheel on the front of
our tandem for a while, and patting myself on the proverbial back that I
had no problems. But that was only until I had occasion to ride it
across a grass field at a local park. Even though I was by myself on
the bike, it popped a spoke after a minute or two.
How you ride really makes a difference. On the roads, I'm a light,
easy-on-gear, rider, but all it takes is one unexpected pothole to cause
enough stress to your wheels to make them fail. Your bodyweight is only
one consideration.
-S-
landotter
alloy. Tension that's enough to crack them is enough to destroy most
other similar rims, regardless of brand.
Jobst Brandt
> I have a set of Areoheads based on a set of Dura Ace hubs with the
> 18/24 combination.
> Great wheels if you consider them race day only. I normally use
> them for Criterium racing and longer/hillier sportifs.
> I have had a couple of problems though, just the rear rim hitting a
> pothole and have just recently replaced the front due to cracking
> around the nipples.
> Considering the front was 2 years old and had not even needed a
> truing during this time leads me to think I hit something but did
> not notice it at the time.
I think the assessment of wheel durability is misplaced. When I
consider the many miles on unpaved or cobble roads that my wheels have
crossed in the more than 30 years (since I wrote "the Bicycle Wheel"),
The same MA-2 rims, that even had a pinch flat or so, are still
working well with their 36 spoke Campagnolo RECORD hubs.
OH! but they aren't as light as CF wheels are as aerodynamic as 18
spoke wheels. I can only ask, "What is the goal of your wheels?" I
think I made clear what causes fatigue failures and how these stresses
are avoided by stress relieving wheels after tensioning.
If it isn't to light to ride any distance than it's not good enough
for most riders who spent too much buying the bicycle with not enough
interest in riding, all the while visualizing themselves a "racers".
Jobst Brandt
John Dacey
<jbr...@sonic.net> wrote:
>I think the assessment of wheel durability is misplaced. When I
>consider the many miles on unpaved or cobble roads that my wheels have
>crossed in the more than 30 years (since I wrote "the Bicycle Wheel"),
>The same MA-2 rims, that even had a pinch flat or so, are still
>working well with their 36 spoke Campagnolo RECORD hubs.
>
>OH! but they aren't as light as CF wheels are as aerodynamic as 18
>spoke wheels. I can only ask, "What is the goal of your wheels?" I
>think I made clear what causes fatigue failures and how these stresses
>are avoided by stress relieving wheels after tensioning.
>
>If it isn't to light to ride any distance than it's not good enough
>for most riders who spent too much buying the bicycle with not enough
>interest in riding, all the while visualizing themselves a "racers".
Mitty League players are certainly not confined to the ranks of
cyclists, and if it provides some impetus for someone to drag himself
out of bed early enough to ride, where's the harm? We already have the
Tea Party making decisions about how people should think without rbt
contributors belittling those who structure their equipment priorities
differently than you.
*********************************
Escaping Volatiles
A volatile Jobst Brandt to Interbike went
To vent his frustrations previously pent:
"Our tube repairs now are failing in batches -
Patches!? We don't need non-syncing patches!!!"
*********************************
Oh, as to the original poster - in my opinion a 20x24 spoked wheelset
will want rims with at least 30 mm depth, even for a rider with your
modest body weight. Consider the Velocity Deep Vee, DT RR 1.2 or
models like them.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983
Extensive catalogue of track equipment: online since 1996
http://businesscycles.com
-------------------------------
Chalo
Assuming Velocity rims, 700c wheels, and 20/24 spoke lacing (the
latter being your fundamental mistake):
Aerohead/Aerohead OC would be appropriate for a child or a child-sized
woman.
Fusion would be OK for a lightweight adult male (like yourself) if
he's a careful rider.
Deep V would serve an average sized American man.
For an above average size man, a B43 in the rear would be a good
idea.
The Dyad and Chukker would appear in these recommendations, but they
are not available in 20h or 24h drilling. You give up a lot when you
subtract a dozen spokes from the time-proven formula for a reliable
wheel.
Chalo
Jobst Brandt
>> I think the assessment of wheel durability is misplaced. When I
>> consider the many miles on unpaved or cobble roads that my wheels
>> have crossed in the more than 30 years (since I wrote "the Bicycle
>> Wheel"), The same MA-2 rims, that even had a pinch flat or so, are
>> still working well with their 36 spoke Campagnolo RECORD hubs.
>> OH! but they aren't as light as CF wheels are as aerodynamic as 18
>> spoke wheels. I can only ask, "What is the goal of your wheels?"
>> I think I made clear what causes fatigue failures and how these
>> stresses are avoided by stress relieving wheels after tensioning.
>> If it isn't to light to ride any distance than it's not good enough
>> for most riders who spent too much buying the bicycle with not
>> enough interest in riding, all the while visualizing themselves a
>> "racers".
> Mitty League players are certainly not confined to the ranks of
> cyclists, and if it provides some impetus for someone to drag himself
> out of bed early enough to ride, where's the harm? We already have the
> Tea Party making decisions about how people should think without RBT
> contributors belittling those who structure their equipment priorities
> differently than you.
I am not prescribing how people should choose their equipment, only
that more sturdy equipment exists and that it might be worth using,
considering that these "standards" were developed almost 100 years
ago.
> *********************************
> Escaping Volatiles
> A volatile Jobst Brandt to InterBike went To vent his frustrations
> previously pent: "Our tube repairs now are failing in batches -
> Patches!? We don't need non-syncing patches!!!"
> *********************************
Please explain what the "Escaping Volatiles" item has to do with wheel
durability. The comment also says nothing about tire patching.
> Oh, as to the original poster - in my opinion a 20x24 spoked
> wheel-set will want rims with at least 30 mm depth, even for a rider
> with your modest body weight. Consider the Velocity Deep Vee, DT RR
> 1.2 or models like them.
Don't com-lain if they don't handle well in crosswinds, or for that
matter, headwinds.
> -------------------------------
> John Dacey
> Business Cycles, Miami, Florida
> Since 1983
> Extensive catalogue of track equipment: online since 1996
> http://businesscycles.com
> -------------------------------
What is the purpose of the commercial sig?
Jobst Brandt
Ben C
[...]
>> I have a set of Areoheads based on a set of Dura Ace hubs with the
>> 18/24 combination.
>
>> Great wheels if you consider them race day only. I normally use
>> them for Criterium racing and longer/hillier sportifs.
>
>> I have had a couple of problems though, just the rear rim hitting a
>> pothole and have just recently replaced the front due to cracking
>> around the nipples.
>
>> Considering the front was 2 years old and had not even needed a
>> truing during this time leads me to think I hit something but did
>> not notice it at the time.
>
> I think the assessment of wheel durability is misplaced. When I
> consider the many miles on unpaved or cobble roads that my wheels have
> crossed in the more than 30 years (since I wrote "the Bicycle Wheel"),
> The same MA-2 rims, that even had a pinch flat or so, are still
> working well with their 36 spoke Campagnolo RECORD hubs.
>
> OH! but they aren't as light as CF wheels are as aerodynamic as 18
> spoke wheels. I can only ask, "What is the goal of your wheels?" I
> think I made clear what causes fatigue failures and how these stresses
> are avoided by stress relieving wheels after tensioning.
If that were true, then why wouldn't it work for 24 or 18 spoke wheels?
Jobst Brandt
For the same reason four steel spoked wheels don't work. Load
concentration is too great at the few spokes that there are. If you
look at the load diagrams in "the Bicycle Wheel" you'll notice that a
18-spoke wheel will have its entire load on essentially one spoke
instead of four or more.
You might read about it. Bike shops sell books, as does Amazon.
http://www.avocet.com/wheelbook/wheelbook.htmlq
http://tinyurl.com/22v535
Jobst Brandt
carl...@comcast.net
Dear Jobst,
Can you give us some load calculations or diagrams on 24 and 18 spoke
figures?
Cheers,
Carl Fogel
Jobst Brandt
>> Ben C (who?) wrote:
>> http://www.avocet.com/wheelbook/wheelbook.htmlq
>> http://tinyurl.com/22v535
> Can you give us some load calculations or diagrams on 24 and 18
> spoke figures?
Look at the deflection plots for rim deflection and how many spokes
that covers for the rim indicated. That deflection is load dependent
and with 18 spokes that puts it all on one spoke. Use your own
calculations for that. This is a linear system with deflection being
a constant.
I take it you are a low spoke count advocate or you wouldn't [pose
such a hostile question. Why do you think old tandem wheels had so
many spokes?
Jobst Brandt
Jobst Brandt
... and always ride low tire pressure and on smooth roads. Just
because you are not overweight for a full sized citizen, doesn't spare
your wheel the peak loads of a rough road.
Jobst Brandt
Tom Sherman °_°
> [...]
> I take it you [Carl Fogel] are a low spoke count advocate or you wouldn't [pose
> such a hostile question.[...]
Or it is just Mr. Fogel being Mr. Fogel.
--
Tom Sherman - 42.435731,-83.985007
I am a vehicular cyclist.
John Dacey
>John Dacey wrote:
>>> If it isn't to light to ride any distance than it's not good enough
>>> for most riders who spent too much buying the bicycle with not
>>> enough interest in riding, all the while visualizing themselves a
>>> "racers".
>
>> Mitty League players are certainly not confined to the ranks of
>> cyclists, and if it provides some impetus for someone to drag himself
>> out of bed early enough to ride, where's the harm? We already have the
>> Tea Party making decisions about how people should think without RBT
>> contributors belittling those who structure their equipment priorities
>> differently than you.
>
>I am not prescribing how people should choose their equipment, only
>that more sturdy equipment exists and that it might be worth using,
>considering that these "standards" were developed almost 100 years
>ago.
Perhaps I've misunderstood your intent, but your bluenosed comments
above about how much people spend on their bikes and how much interest
they might have in riding sounds pretty judgmental to me. In any
event, your finding that we've made no progress in bicycle technical
matters in one hundred years is just too depressing to consider.
>> *********************************
>> Escaping Volatiles
>
>> A volatile Jobst Brandt to InterBike went
>>To vent his frustrations previously pent:
>> "Our tube repairs now are failing in batches -
>> Patches!? We don't need non-syncing patches!!!"
>
>> *********************************
>
>Please explain what the "Escaping Volatiles" item has to do with wheel
>durability. The comment also says nothing about tire patching.
It doesn't have a single thing to do with the subject of this thread.
I dashed those lines out for the discussion on Rema patches, but
workload got in the way of reading this group when the topic was still
current. I decided to inject it here just because. By the way, the
last line should be recited as heard here:
http://www.rudebadmood.com/badges/bsbadges.wav
>> Oh, as to the original poster - in my opinion a 20x24 spoked
>> wheel-set will want rims with at least 30 mm depth, even for a rider
>> with your modest body weight. Consider the Velocity Deep Vee, DT RR
>> 1.2 or models like them.
>
>Don't com-lain if they don't handle well in crosswinds, or for that
>matter, headwinds.
Please, not this old bugbear again. Rims of this (30 mm or so) profile
are barely deep enough to have even a slender aero benefit, so at the
same time they're not a sufficiently effective airfoil to regularly
create seriously adverse handling issues.
>
>> -------------------------------
>> John Dacey
>> Business Cycles, Miami, Florida
>> Since 1983
>> Extensive catalogue of track equipment: online since 1996
>> http://businesscycles.com
>> -------------------------------
>
>What is the purpose of the commercial sig?
>
>Jobst Brandt
It identifies me and is automatically appended to outgoing email
messages and usenet posts by the newsreader I use. Similar signatures
seem commonly used by other posters with bike shop connections or
other bicycle industry affiliations (current participants as well as
those who no longer post here). I can't recall anyone ever commenting
on it before - do you object?
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983
Our catalog of track equipment: online since 1996
http://businesscycles.com
-------------------------------
Ben C
Why should that matter? Are you saying that even "stress-relieved"
spokes in a 36H wheel are in places within 25% of their yield stress?
andre...@aol.com
This does not necessarily answer your question, but I thought that I
share this. I bought a vuelta xrp wheelset with 20/24 spokes and 30 mm
rims for $150. they weigh 850 and 1150 respectively. I'm about 200
pounds. When I got the wheels, the only thing that I did was to
squeeze parallel spokes together. I put over 5000 miles on the wheels
and they are still absolutely straight and true. I don't know how long
the wheels will last, but so far they have been remained truer than
almost anything I've had before. I am not gentle with my stuff and
ride over rails, bumpy roads etc, etc. I ride with narrow tires and a
lot or pressure which lets the rims absorb a lot of the impact.
Vuelta also mades wheels with the same rims by 32 spokes. They are
supposed to to handle 300lbs.
I think that since god invented wheels from china and taiwan, the need
to build you own wheels, unless you need something very unique, has
become obsolete.
Ed
Steve,
As I understand it you have a set of hubs you would like to re rim and
you would like your work to last more than 5000 miles.
A key point is: suddenly applied loads double the stress on any
structure when compared to statically applied loads.
In your experience 32 hole rims last at least twice as long as 20/24
hole rims and the weak point appears to be the rim (where some rims
have an eyelet).
I am not convinced an eyelet is goint to solve things unlessyou get
one that transfers the force to the inner wall of the rim - I don't
think they make those any more.
If I were trying to get more miles out of those hubs - or specifically
rims attached to those hubs - I would select a rim that could be run
at the lowest pressure possible (consistent wth Josh above). That
would mean tubeless at 80 lbs. I am told the A23 was designed to be
convertered and I know that Stan's Alpha rims were designed to be run
tubeless.
A key point is I've been told the spoke that is supporting the weight
is the spoke in tension immediately above the hub. All the other
spokes are keeping the wheel round as the top of the rim tries to
deform inward. The more the top of the rim can deform inward the more
the load on the spoke above the hub is reduced. Long story short: a
shallow section like the A23 should reduce the peak loads on the
eyelet area amd tubeless at low pressures shuld reduce the suddeness
of the load effectively reducing the peak stress on the eyelet area.
Use the A23 tubeless if you want ot stick with those hubs.
Tom Sherman °_°
> [...]
> A key point is I've been told the spoke that is supporting the weight
> is the spoke in tension immediately above the hub. All the other
> spokes are keeping the wheel round as the top of the rim tries to
> deform inward. The more the top of the rim can deform inward the more
What you were told has been proven wrong. In a spoked tension wheel, in
normal service, vertical loads are carried by loss of pretension in the
*bottom* spokes:
<http://www.astounding.org.uk/ian/wheel/>,
<http://www.duke.edu/~hpgavin/papers/HPGavin-Wheel-Paper.pdf>,
<http://www.rose-hulman.edu/~fine/FE2002/Projects/Hartz.pdf>,
and of course <http://www.avocet.com/wheelbook/wheelbook.html>.
landotter
Or if you simply need a set of 135mm spaced touring or cross wheels.
For mtb or racy road, you're pretty right.
Jobst Brandt
>>>>> I have a set of Areoheads based on a set of Dura Ace hubs with
>>>>> the 18/24 combination.
>>>>> Great wheels if you consider them race day only. I normally use
>>>>> them for Criterium racing and longer/hillier sportifs.
>>>>> I have had a couple of problems though, just the rear rim
>>>>> hitting a pothole and have just recently replaced the front due
>>>>> to cracking around the nipples.
>>>>> Considering the front was 2 years old and had not even needed a
>>>>> truing during this time leads me to think I hit something but
>>>>> did not notice it at the time.
>>>> I think the assessment of wheel durability is misplaced. When I
>>>> consider the many miles on unpaved or cobble roads that my wheels
>>>> have crossed in the more than 30 years (since I wrote "the
>>>> Bicycle Wheel"), the same MA-2 rims, that even had a pinch flat
>>>> or so, are still working well with their 36 spoke Campagnolo
>>>> RECORD hubs.
>>>> OH! but they aren't as light as CF wheels are as aerodynamic as
>>>> 18 spoke wheels. I can only ask, "What is the goal of your
>>>> wheels?" I think I made clear what causes fatigue failures and
>>>> how these stresses are avoided by stress relieving wheels after
>>>> tensioning.
>>> If that were true, then why wouldn't it work for 24 or 18 spoke
>>> wheels?
>> For the same reason four steel spoked wheels don't work. Load
>> concentration is too great at the few spokes that there are. If
>> you look at the load diagrams in "the Bicycle Wheel" you'll notice
>> that a 18-spoke wheel will have its entire load on essentially one
>> spoke instead of four or more.
> Why should that matter? Are you saying that even "stress-relieved"
> spokes in a 36H wheel are in places within 25% of their yield
> stress?
THE RIM! Get the message. Spokes can be made to support great loads,
but rims crack and that is the subject of this thread. Stop the
mis-attributions and out of context depictions.
Jobst Brandt
Steve Sr.
The road conditions her in central North Carolina are generally not to
bad with relatively few potholes. I do try to lift the front wheel
over any big bumps like railroad tracks. However, this does nothing
for the rear wheel. I also wouldn't consider myself overly strong or
agressive.
Steve
Jobst Brandt
>> I am considering rebuilding a set of wheels that had Alex 20/24
>> hole rims. They went about 5K miles before the spokes started to
>> pull thorough the rims.
>> I am considering using these hubs and Velocity Aerohead and
>> Aerohead O/C rims but am wondering about the durability because of
>> my previous experience with the Alex rims.
>> I currently have a set of these Velocity rims but in 32 hole
>> configuration that have been flawless for the past 10K miles.
>> BTW, I only weigh about 160 pounds.
> As I understand it you have a set of hubs you would like to re rim
> and you would like your work to last more than 5000 miles.
> A key point is: suddenly applied loads double the stress on any
> structure when compared to statically applied loads.
> In your experience 32 hole rims last at least twice as long as 20/24
> hole rims and the weak point appears to be the rim (where some rims
> have an eyelet).
> I am not convinced an eyelet is going to solve things unless you get
> one that transfers the force to the inner wall of the rim - I don't
> think they make those any more.
> If I were trying to get more miles out of those hubs - or
> specifically rims attached to those hubs - I would select a rim that
> could be run at the lowest pressure possible (consistent with Josh
> above). That would mean tubeless at 80 lbs. I am told the A23 was
> designed to be convertered and I know that Stan's Alpha rims were
> designed to be run tubeless.
> A key point is I've been told the spoke that is supporting the
> weight is the spoke in tension immediately above the hub. All the
> other spokes are keeping the wheel round as the top of the rim tries
> to deform inward. The more the top of the rim can deform inward the
> more the load on the spoke above the hub is reduced. Long story
> short: a shallow section like the A23 should reduce the peak loads
> on the eyelet area and tubeless at low pressures should reduce the
> suddeness of the load effectively reducing the peak stress on the
> eyelet area.
You have been misled (pronounced my-seld) again. The load is carried
by compressing the bottom spokes between hub and road. If they are
too loose and become slack from loading, the spoke nipples unscrew or
worse, the wheel collapses, having no lateral rim position for lack of
spoke pull to the sides.
> Use the A23 tubeless if you want ot stick with those hubs.
What does "tubeless" have to do with cracking rims?
Jobst Brandt
Ed
Thank you. This is helpful. I was just told " a pint a pound the
world around" wasn't true just this week as well.
Deformaton at the bottom makes a lot more sense. I did not see a tire
modeled as a set of spokes in tension extending out from the rim. The
loss of tension in these rubber spokes is what unloads the part of the
rim near the contact patch. That unloading is what propogates into the
actual spokes. So the free body diagram of rim loads should cut the
tire just outside the bead, replacing them with vectors. Anyway...
The question is at 20/24 will a tall section rim have better life at
the nipple hole. The math seems to say the amount of cyclic stress
where the nipple contacts the rim is reduced if the rim is stiffer.
I've had more trouble with purchased deep sectioned rimmed wheels than
any I have made myself on shallower sections.
...Maybe the difference was not the section depth.
Ed
>
> - Show quoted text -
Tubeless allows lower tire pressures which means less sudden loading
conditions and a larger contact patch. The larger contact patch un
loads the rim over a larger area (this is based on the free body
digram of all road to rim loads being imposed by tire forces at the
bead.). The smeared unloading should reduce the peak cyclic load on
the part of the rim that holds the nipple. The part that cracks.
Steve Sr.
wrote:
>Hello,
>
>I am considering rebuilding a set of wheels that had Alex 20/24 hole
>rims. They went about 5K miles before the spokes started to pull
>thorough the rims.
>
>I am considering using these hubs and Velocity Aerohead and Aerohead
>O/C rims but am wondering about the durability because of my previous
>experience with the Alex rims.
>
>I currently have a set of these Velocity rims but in 32 hole
>configuration that have been flawless for the past 10K miles.
>
>BTW, I only weigh about 160 pounds.
>
>Thanks,
>
>Steve
Thanks for everyones input. I agree with Andrew that the spoke count
is on low side for durability.
As I mentioned, the original rims started to fail at about 5K miles
and were replaced under warranty. The new set had about 5K miles on
them when a minor crash took out the front wheel. Since I have 5K on
the rear which is where the original failed I was planning on
rebuilding both to be done with it. Were these over tensioned? I have
no way of knowing.
I am primarily looking at rebuilding these as a secondary/spare set
and not wanting to break the bank doing it. This includes reusing the
spokes if at all possible. This is one reason why I was looking at the
Aerohead. I believe that the ERD was close enough to use the old
spokes. The hubs are radial in the front and radial/3 cross in the
rear if that matters.
Steve
Chalo
>
> I am not convinced an eyelet is goint to solve things unless you get
> one that transfers the force to the inner wall of the rim - I don't
> think they make those any more.
A single eyelet (grommet) serves two valuable purposes: It provides a
better bearing surface for the spoke nipple head, and it helps prevent
galling damage at the drilling from initiating cracks into the rim
extrusion.
Double eyelets (sockets) are still offered by Mavic, Rigida, and Alex
on a few models. Whether they actually transfer any load to the
internal wall of the rim depends on the specifics of the socket and
the rim extrusion and manufacturing tolerances. On modern deep and
semi-deep section rims, sockets offer the benefit of keeping nipples
from going astray within the rim channel while the wheel is being
laced.
Chalo
AMuzi
Another path is to give those hubs away and get a set of 36h
Shimano hubs. Hubs are an area in which Shimano shines, dirt
cheap and very tough. Rims cost the same in any drill.
You'd also have the opportunity to build 3x front and rear.
Bonus.
--
Andrew Muzi
<www.yellowjersey.org/>
Open every day since 1 April, 1971
landotter
Alex R390s have been nothing but rock solid in my experience. Not too
light or too heavy, much like a CR18 in that regard. Socketed and
cheap. If they hold up to my buddy Shep, they'll pretty much stand up
to most folks.
AMuzi
landotter
Probably more like 500g on a real scale. A proper amount of metal for
real world use. The Adventurers I built up scaled at something like
650g. With 900g 47mm Continentals. The trick is to stay at speed. ;-)
And ride with slow clydes.
DirtRoadie
> The hubs are radial in the front and radial/3 cross in the
> rear if that matters.
24H, 3x? Does not seem likely.
DR
Jay Beattie
The R390 web-page claims that it is a racing and tri rim, 500g seems
pretty heavy for a racing rim. -- Jay Beattie.
landotter
Certainly. However, it's a damn good rim for non-racing roadies who
want durability. I do have a feeling that it probably wouldn't slow
any champs down compared to an OP.
dusto...@mac.com
> I am considering rebuilding a set of wheels that had Alex 20/24 hole
> rims. They went about 5K miles before the spokes started to pull
> thorough the rims.
>
> I am considering using these hubs and Velocity Aerohead and Aerohead
> O/C rims but am wondering about the durability because of my previous
> experience with the Alex rims.
>
> I currently have a set of these Velocity rims but in 32 hole
> configuration that have been flawless for the past 10K miles.
>
> BTW, I only weigh about 160 pounds.
If you haven't already:
<http://www.sheldonbrown.com/rinard/spocalc.htm>
Your rims and the Velocity rims are probably in there so you can see
what spoke lengths you're dealing with.
Here are the Deep V's, if you haven't looked at the online USA catalog
yet:
<http://www.velocityusa.com/default.asp?contentID=583>
I wouldn't pretend to know what a 160lb. rider could get away with,
IRT Aerohead v. Deep V's. The Deep V's are strong enough to be a
favored tandem rim and recommended, as you have seen from at least one
expert here, also for low spoke count wheels. "Take the mass out of
the spokes, put it in the rim", so to speak, and gain an aero
advantage from fewer spokes, if not much "aero gain" from a 30mm-deep
rim.
At well over 200lbs, I've had excellent results from 32 and 36h
Velocity Aerohead and Aerohead OC (rear) rims with the exception of
one machined-sidewall OC rear, which gave up the ghost very early,
probably due to over-machining which thinned the sidewall to extreme.
It cracked out in typical fashion for worn rims that have seen a lot
of brake application, the sidewall parting from the "spoke bed". So,
I'd go with the non-machined sidewall variety, which will be a little
stronger and last longer, whichever rim you look at.
BTW: Those OC's have built two of the strongest rear wheels I've had
so far, judging by staying true.
I don't know what kind of hubs you have but their condition would
figure into this equation, too. Even given low milage and "event"
status, meaning "not used much in the rain", I would guess. If they're
serviceable, I'd get them inspected and serviced, if they're not
heavily worn, for starters.
Noting, the old Campy Shamal wheels (40-41mm deep), at least in the 16-
spoke version, front and rear, had a reputation for good service. The
12-spoke Shamals seemed to be known for spoke breakage but the 16'ers
were good. I have a set of 16's, have put some miles on them with no
problems, including no spoke pull-through, even without ferrules. Not
dicey in strong winds for a heavy rider, IME.
--D-y
carl...@comcast.net
Dear Jobst,
So questions are hostile?
I asked for your calculations, which seem to be missing for 24 and 18
spoke wheels. That is, what is the expected load, what is the tension
loss, and what is the expected fatigue factor?
I'd be more convinced of the perfection of 36-spoke wheels front and
rear if a few points were addressed.
A) The 36-spoke wheels were developed in the 1890s for rather badly
built steel and wooden rims, 30 to 40 years before aluminum rims, and
a century before modern deep-section rims.
B) The 36-spoke wheels are either over-built for front wheels (~20%
less load and yet robustly symmetrical), or else under-built for rear
wheels (~20% more load and yet weakened by dishing).
C) How can 36-spoke wheels be just right for riders 140 to 220 pounds
forty pounds on either side of your 180 pounds? Three dozen holes,
front and rear, sounds more like a convenient manufacturing figure,
one that has largely disappeared.
C) Bicycle spokes improved from plain rusty steel, to galvanized
steel, to stainless steel, and finally to stainless steel that's so
ductile that it simply stretched without breaking in your second round
of spoke tests over twenty years ago:
"In contrast to tests performed for the first edition of this book
[1981] these spokes withstood substantial elongation before failure.
Some butted spokes stretched more than six millimeters without
breaking, at which point the test was stopped."
--Jobst Brandt, "The Bicycle Wheel," 2nd Edition, 1988, p.132
More evidence of impressive improvement in spoke material and quality:
"It appears that the better spokes now available [1993] would have
made the discovery of many of the concepts of this book more difficult
for lack of failure data. I am grateful in retrospect for the poor
durability of earlier spokes. They operated so near their limits that
durability was significantly altered by the techniques that I have
outlined."
--Jobst Brandt, "The Bicycle Wheel," 3rd Edition, 1993, p.124
Other people noticed the improvement in spokes and found that they
could build good wheels with deep section rims and far fewer spokes.
D) The typical load on a bicycle wheel, front or rear, is only about
100 pounds. Losing that much tension is easily within the operating
range of a single modern stainless steel spoke, with its typical 200
pounds of tension. Why do you think that your stress-relief technique
would fail in this situation? And why would the straight-pull spokes
popular on low-spoke-count wheels suffer at all?
E) If millions of riders weren't happily riding around on
low-spoke-count wheels without bothering to carry the spare spokes
that were routinely carried thirty years ago on 36-spoke wheels. I
doubt that Mike Jacoubowsky at Chain Reaction Bicycles is selling
bikes whose spokes snap like twigs. Nor do I think that Jay Beattie is
having problems with his low-spoke-count wheels.
It would be nice if you re-did "The Bicycle Wheel" and addressed the
huge change in wheels since 1981.
Cheers,
Carl Fogel
Chalo
>
> landotter wrote:
> >
> > Chalo wrote:
> >>
> >> Double eyelets (sockets) are still offered by Mavic, Rigida, and Alex
> >> on a few models.
> >
> > light or too heavy, much like a CR18 in that regard. Socketed and
> > cheap. If they hold up to my buddy Shep, they'll pretty much stand up
> > to most folks.
>
> At 485g I'd expect so: http://www.alexrims.com/product_detail.asp?btn=1&cat=1&id=44
TANSTAAFL. That's the same as a velocity Synergy and lighter than the
deep rims all the cool kids are riding these days.
When a 750g rim can tolerate a triplet team, and a 375g rim is
struggling just to make it to the finish line, why push the limits of
reliability? Each extra gram in there delivers more than its weight
in confidence.
Chalo
andre...@aol.com
Indestructible and unbeatable price: double eyelet:
http://bikeisland.com/cgi-bin/BKTK_STOR20.cgi?Action=Details&ProdID=1847
andre...@aol.com
sorry no double eyelet.
andre...@aol.com
If you wish to carry an elephant on your bike:
http://bikeisland.com/cgi-bin/BKTK_STOR20.cgi?Action=Details&ProdID=1776
Frank Krygowski
Jobst is just a shy, sensitive guy. Sometimes he lets his feelings
get hurt.
> I'd be more convinced of the perfection of 36-spoke wheels front and
> rear if a few points were addressed....
To me, it's obvious that wheels with fewer spokes (or even lighter
rims) than "classic" ones can give life that's acceptable to many
riders. Heck, for a long time British bikes featured different spoke
counts front and rear, before an examination of costs vs. benefit
moved them to 36 spokes front and rear.
But while the technical questions Carl asked are interesting, I tend
to look at things the other way. Let's skip the details and go to
ideal (i.e. vaporware?) wheels.
How much difference would a rider notice if he rode wheels that had
zero mass and zero aerodynamic drag? My guess is, not much.
Just as a Carnot engine dispels wild daydreams about super-efficient
land barges, I think vaporware wheels dispel wild daydreams about
winning sprints because of having one fewer spoke.
IOW, the total theoretical benefit is not very great. The small
fraction of that benefit that comes from increasingly exotic
contraptions is probably not worth much at all. Unless you're the
manufacturer, or the magazine carrying his ads.
- Frank Krygowski
DirtRoadie
> IOW, the total theoretical benefit is not very great.
Yes, by all means. Let's wipe away any thought of technical discussion
because one person's opinion chooses to "skip the details" and thereby
deem any changes (improvements OR dead ends) unworthy.
How is your abacus connected to the web?
DR
Jobst Brandt
>>>> http://www.avocet.com/wheelbook/wheelbook.htmlq
>>>> http://tinyurl.com/22v535
> Dear Jobst,
> So questions are hostile?
Yes, when the answers are present and you repeat old complaints.
> I asked for your calculations, which seem to be missing for 24 and 18
> spoke wheels. That is, what is the expected load, what is the tension
> loss, and what is the expected fatigue factor?
> I'd be more convinced of the perfection of 36-spoke wheels front and
> rear if a few points were addressed.
They have been and the issues for average intelligent readers are
apparent.
> A) The 36-spoke wheels were developed in the 1890s for rather badly
> built steel and wooden rims, 30 to 40 years before aluminum rims,
> and a century before modern deep-section rims.
> B) The 36-spoke wheels are either over-built for front wheels (~20%
> less load and yet robustly symmetrical), or else under-built for
> rear wheels (~20% more load and yet weakened by dishing).
I think you need to review what has been presented in "the Bicycle
Wheel". For instance, "dishing" has mainly affected lateral wheel
strength rather than load carrying capacity. Fifty years ago, I rode
wood rims to avoid tubular glue melting on long mountain descants.
They served well but brake pad wear was more rapid from higher contact
temperatures.
> C) How can 36-spoke wheels be just right for riders 140 to 220 pounds
> forty pounds on either side of your 180 pounds? Three dozen holes,
> front and rear, sounds more like a convenient manufacturing figure,
> one that has largely disappeared.
This seems to be getting into a long "homework assignment". How about
doing your own homework?
> C) Bicycle spokes improved from plain rusty steel, to galvanized
> steel, to stainless steel, and finally to stainless steel that's so
> ductile that it simply stretched without breaking in your second round
> of spoke tests over twenty years ago:
All those lesser spokes suffered from was corrosion rather than
structural failure. Chromed steel spokes were also long lived and
and shinier than stainless ones.
> "In contrast to tests performed for the first edition of this book
> [1981] these spokes withstood substantial elongation before failure.
> Some butted spokes stretched more than six millimeters without
> breaking, at which point the test was stopped."
> --Jobst Brandt, "The Bicycle Wheel," 2nd Edition, 1988, p.132
> More evidence of impressive improvement in spoke material and quality:
That doesn't mean they were better spokes, but it affected testing.
> "It appears that the better spokes now available [1993] would have
> made the discovery of many of the concepts of this book more
> difficult for lack of failure data. I am grateful in retrospect for
> the poor durability of earlier spokes. They operated so near their
> limits that durability was significantly altered by the techniques
> that I have outlined."
> --Jobst Brandt, "The Bicycle Wheel," 3rd Edition, 1993, p.124
However, with suitable building techniques, spokes lasted a long time.
That doesn't absolve the 'low spoke count' people from cracking rims.
> Other people noticed the improvement in spokes and found that they
> could build good wheels with deep section rims and far fewer spokes.
You are scratching the bottom of the barrel with your comments. Write
a book if you are so sure of all this.
> D) The typical load on a bicycle wheel, front or rear, is only about
> 100 pounds. Losing that much tension is easily within the operating
> range of a single modern stainless steel spoke, with its typical 200
> pounds of tension. Why do you think that your stress-relief
> technique would fail in this situation? And why would the
> straight-pull spokes popular on low-spoke-count wheels suffer at
> all?
> E) If millions of riders weren't happily riding around on
> low-spoke-count wheels without bothering to carry the spare spokes
> that were routinely carried thirty years ago on 36-spoke wheels. I
> doubt that Mike Jacoubowsky at Chain Reaction Bicycles is selling
> bikes whose spokes snap like twigs. Nor do I think that Jay Beattie
> is having problems with his low-spoke-count wheels.
> It would be nice if you re-did "The Bicycle Wheel" and addressed the
> huge change in wheels since 1981.
Do it! You seem to believe you have all the correct answers.
Jobst Brandt
Mike Jacoubowsky
news:cjbcd690i2ndvsklg...@4ax.com...
This is a point that many/most simply don't get. Your are actually
underestimating the differences in damaging forces applied to the rear
wheel vs front, because you've left out the effects of drive torque
which, unless you have a disc front wheel, exist only for the rear.
> C) How can 36-spoke wheels be just right for riders 140 to 220 pounds
> forty pounds on either side of your 180 pounds? Three dozen holes,
> front and rear, sounds more like a convenient manufacturing figure,
> one that has largely disappeared.
Yet there is even greater variability in pedaling style that creates
more, or less, stress for the rear wheel. It took some time, but Keith
Bontrager did manage to explain to me why it was the lower-gear strong
rider who was far more prone to spoke & rim failure than a guy like
Jobst using his massively-huge (compared to most mortals) gears when
climbing. Consider an overpowered motorcycle that can break a chain in
1st gear. It would never happen in a taller gear. Peak loads are much
higher for the low-gear guy than the high-gear guy, and it's the
loading/unloading cycles that kill things. Jobst gives far too little
credit for his wheel longevity to his unusual riding style. (I still
didn't believe Keith; it just seems wrong to believe that the big gear
masher isn't doing his best to destroy things, but empirical evidence
tells me he's absolutely correct, at least for wheels. We see the same
situation for frames as well, but it's not so obvious because larger
frames are significantly more affected by structural issues (since
builders don't usually "scale" well when they go from smaller to larger
frames), and Jobst's frame size is kind off the chart. He's going to
break them just because he's very tall and very strong. Maybe he'd break
them even faster if he used lower gears? I don't know. Jobst is special.
:-)
> C) Bicycle spokes improved from plain rusty steel, to galvanized
> steel, to stainless steel, and finally to stainless steel that's so
> ductile that it simply stretched without breaking in your second round
> of spoke tests over twenty years ago:
>
> "In contrast to tests performed for the first edition of this book
> [1981] these spokes withstood substantial elongation before failure.
> Some butted spokes stretched more than six millimeters without
> breaking, at which point the test was stopped."
>
> --Jobst Brandt, "The Bicycle Wheel," 2nd Edition, 1988, p.132
>
> More evidence of impressive improvement in spoke material and quality:
>
> "It appears that the better spokes now available [1993] would have
> made the discovery of many of the concepts of this book more difficult
> for lack of failure data. I am grateful in retrospect for the poor
> durability of earlier spokes. They operated so near their limits that
> durability was significantly altered by the techniques that I have
> outlined."
>
> --Jobst Brandt, "The Bicycle Wheel," 3rd Edition, 1993, p.124
>
> Other people noticed the improvement in spokes and found that they
> could build good wheels with deep section rims and far fewer spokes.
The Robergel 3* spokes that were so popular in the 70s were complete
garbage compared to what we have today. Union spokes were little, if
any, better. It wasn't until I discovered the Robergel Sport galvanized
steel spoke that I found my first lasts-forever wheel product. Ugly as
you can imagine, but never broke (and cheap!). It was probably around
1990 or so that spokes became generally reliable enough that you didn't
have to worry about them, at least not from Wheelsmith or DT.
> D) The typical load on a bicycle wheel, front or rear, is only about
> 100 pounds. Losing that much tension is easily within the operating
> range of a single modern stainless steel spoke, with its typical 200
> pounds of tension. Why do you think that your stress-relief technique
> would fail in this situation? And why would the straight-pull spokes
> popular on low-spoke-count wheels suffer at all?
Are we talking about spoke failure with low-spoke-count wheels or rims?
Spokes typically aren't the issue. It's the increased loading on each
section of rim that interfaces with the nipple, and for reasons I cannot
fathom, nobody's figured out how to spread that load better. Rim failure
is invariably minor at the beginning, and yet detectable. You can see
the small cracks being and slowly expand over time. Rarely does one see
a chunk of rim pulled out. In most cases, the damage remains contained
to a very small area, implying that it wouldn't take much to spread that
load over a large-enough area to prevent it from happening. The rim
structure itself is strong enough for the task, it's just the excessive
loading on a small area that causes the problem.
> E) If millions of riders weren't happily riding around on
> low-spoke-count wheels without bothering to carry the spare spokes
> that were routinely carried thirty years ago on 36-spoke wheels. I
> doubt that Mike Jacoubowsky at Chain Reaction Bicycles is selling
> bikes whose spokes snap like twigs. Nor do I think that Jay Beattie is
> having problems with his low-spoke-count wheels.
I still see spoke failures, typically difficult to explain and likely
caused by either poor quality spokes & manufacturing techniques. Poor
quality spokes head up my list, because they fail despite us having made
sure they were at proper tension and fully bedded in, and the spoke
head/hub interface appears good. Rebuilt by a novice wheelbuilder with
DT or Wheelsmith spokes and they go on forever. There are, I still
believe, some very low quality spokes out there.
> It would be nice if you re-did "The Bicycle Wheel" and addressed the
> huge change in wheels since 1981.
Curiously, this last conversation included reference to Jobst's immortal
MA2 rim (the one that you see in the TV ads where you put it under the
pyramid at night and it becomes stronger every day) and yet didn't
mention the significant changes in rim technology that have come since
then. Spokes have improved, but Jobst is correct to suggest that Mavic
durability (along with many others) has declined greatly as they applied
new materials and surface coatings to rims. I do not think Jobst would
get anywhere near the mileage out of a current high-spoke-count Mavic
rim that he has had with his museum piece.
>
> Cheers,
>
> Carl Fogel
--
--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com
Dan O
I have 36-hole Alex Adventurer rims, weigh more like 200 pounds with
enough tools and a cantalope in my messenger bag, haul more stuff in a
pair of panniers, have a heavy bike to begin with, but still fly off
curbs and ride through almost anything. I'd like it if Santa brought
me a pair of 36-hole Velicity Dyads (I think it was - based on
recommendation of Peter White), but the Alex show no signs of giving
up yet.
> > I think that since god invented wheels from china and taiwan, the need
> > to build you own wheels, unless you need something very unique, has
> > become obsolete.
>
My front wheel is still on the build it came with, and is a sticky,
twisty pain to true. The rear wheel - which I disassembled, soaked
nipples, cleaned and greased spoke threads, greased nipple sockets w/
q-tip, and re-assembled w/ new hub - is running much more true now
than when I got it. It still needs truing, but it's easier now
because the spokes all turn smoothly and feel consistent.
Also, that tensiometer was so worth the $70 or so.
<snip>
Mike Jacoubowsky
news:4cd3facf$0$1616$742e...@news.sonic.net...
> Steve Sr. wrote:
>
>> I am considering rebuilding a set of wheels that had Alex 20/24 hole
>> rims. They went about 5K miles before the spokes started to pull
>> thorough the rims.
>
>> I am considering using these hubs and Velocity Aerohead and Aerohead
>> O/C rims but am wondering about the durability because of my
>> previous experience with the Alex rims.
>
>> I currently have a set of these Velocity rims but in 32 hole
>> configuration that have been flawless for the past 10K miles.
>
>> BTW, I only weigh about 160 pounds.
>
> longer and not fail from local overload at the spoke holes? I think
> you are afflicted with the "fewer spokes are faster" syndrome. In
> that event, I'm surprised you aren't using CF rims, spokes, and
> hubs... that fail even faster than wheels with low spoke-count metal
> rims.
>
> Jobst Brandt
If he needs 36 spoke wheels for his size and style of riding, why aren't
you riding on 48s?
Why the insistence on one-size-fits-all wheel design?
Surely you don't have an issue with bigger guys riding 28c tires. Should
*everyone* be riding 28c tires? I ride 23c tires when it's nice out, 25c
tires when it's not. I like the better traction in rain that I get with
a wider tire. But I like the faster feel of a 23c tire when conditions
are better. I'm pandering to my *DESIRES* and those go beyond simply
having equipment that works no-matter-what. The 23c tires work
wonderfully for me under normal conditions, and I get at most one flat
every 3000 miles. That works for me. 25c tires would work for me too,
but I like 23c better most of the time. Surely this is something you
wouldn't argue with.
Why are wheels any different? Why should one type of wheel be used for
everyone, even though it's likely overbuilt for many and underbuilt for
some? Or do you have no room in your world view for useful design life
and the concept that it's different for something used in different
conditions? Why is it wrong for someone to want something lighter,
especially if it's going to work as well and maybe better for them than
something more "standard" might work for a heavier rider?
We are not all .3hp machines delivering torque in exactly the same
manner and weighing the same.
Dan O
> ... still needs truing, but it's easier now
> because the spokes all turn smoothly and feel consistent.
>
... nipples turn, I mean :-)
dusto...@mac.com
Way back in 1996 Dr. James Martin posted this:
<http://www.eatel.net/~mikec/aero.html>
If you'll read down to RN VI, you'll see "about a minute and a half to
two minutes" given as the advantage between "normal" wheels and aero
wheels (TriSpoke front and disc rear) for a 40k ITT. Which is both a
prediction from modeling and measured "real world" riding.
The "real world" is somewhat anecdotal, as Dr. Martin says, but actual
road results were nearly identical to the prediction.
The Trispoke and disc setup might be extreme, but if LSC/DD wheels
have even half the aero benefit, and modern light LSC/DD wheels gain
from being light, then we're looking at perhaps 45 seconds to a
minute's gain over only 25 miles, of course when ridden at ITT speed.
"What is the purpose of your wheels", indeed. You want rock crushers?
Components are widely available. TT wheels? Same deal, more likely as
a prebuilt wheel, and probably more expensive, especially if you want
both aero and light. "How fast do you want to spend?"
--D-y
Chalo
>
> Frank Krygowski wrote:
> >
> > How much difference would a rider notice if he rode wheels that had
> > zero mass and zero aerodynamic drag? My guess is, not much.
>
> > Just as a Carnot engine dispels wild daydreams about super-efficient
> > land barges, I think vaporware wheels dispel wild daydreams about
> > winning sprints because of having one fewer spoke.
>
> Components are widely available.
Not so much. 48 hole components have fallen by the wayside; many of
the commonest up-to-date parts are available in 32 hole only rather
than 36 hole as in the past. Consumers being willing to play along
with (and even pay more for) manufacturers' rush towards cheapness has
exacted casualties.
> TT wheels? Same deal, more likely as
> a prebuilt wheel, and probably more expensive, especially if you want
> both aero and light. "How fast do you want to spend?"
You can always get what you want if there is no limit to how much you
are willing and able to spend for it. The problem thus created is at
the other end of the market, where inexpensive, rugged field-grade
equipment disappears because the most profitable [suggestible]
fraction of the market has been snookered into buying something less
for more money.
Chalo
DirtRoadie
wrote:
> Yet there is even greater variability in pedaling style that creates
> more, or less, stress for the rear wheel.
>... Jobst using his massively-huge (compared to most mortals) gears when climbing.
[...]
> Peak loads are much
> higher for the low-gear guy than the high-gear guy, and it's the
> loading/unloading cycles that kill things. Jobst gives far too little
> credit for his wheel longevity to his unusual riding style. (I still
> didn't believe Keith; it just seems wrong to believe that the big gear
> masher isn't doing his best to destroy things, but empirical evidence
> tells me he's absolutely correct, at least for wheels.
Yes, good observations and the description of Jobst's "style" is fully
consistent with Jobst's often repeated (too often) claim of the
inadequacy of the long existing pedal/crank interface. He cites as
evidence the number of cranks that _HE_ has broken (now long ago),
evidence which finds little support in the realm of cranks in general
which still use the same interface which they have historically used
for quite some time.
In contrast to a wheel, a crank unquestionably suffers greater forces
from a strong big gear masher. That ONE such individual regularly
breaks (or broke) cranks is hardly dispositive of the issue of the
adequacy of the cranks in general.
DR
DR
DirtRoadie
> the issues for average intelligent readers are apparent.
Jobst,
Carl asked a number of insightful, interesting, relevant and non-
hostile questions.
> Do it! You seem to believe you have all the correct answers.
Apparently you cannot make up your mind whether Carl is asking
questions or providing answers.
If you are not interested in updating you expertise, then kindly save
everyone your arrogance and avoid suggesting others are something
other than "average intelligent readers" unless of course you are
suggesting that Carl is an "above average intelligent reader."
DR
Tom Sherman °_°
> [...]
>> "In contrast to tests performed for the first edition of this book
>> > [1981] these spokes withstood substantial elongation before failure.
>> > Some butted spokes stretched more than six millimeters without
>> > breaking, at which point the test was stopped."
>> > --Jobst Brandt, "The Bicycle Wheel," 2nd Edition, 1988, p.132
>> > More evidence of impressive improvement in spoke material and quality:
> That doesn't mean they were better spokes, but it affected testing.
Indeed, the high ductility of 304 stainless steel does *not* imply
greater fatigue resistance.
--
Tom Sherman - 42.435731,-83.985007
I am a vehicular cyclist.
thirty-six
Like for time trialling, two 13st dudes on 28 spoke front and rear.
thirty-six
dusto...@mac.com
> dustoyevsky wrote:
>
> > Frank Krygowski wrote:
>
> > > How much difference would a rider notice if he rode wheels that had
> > > zero mass and zero aerodynamic drag? My guess is, not much.
>
> > > Just as a Carnot engine dispels wild daydreams about super-efficient
> > > land barges, I think vaporware wheels dispel wild daydreams about
> > > winning sprints because of having one fewer spoke.
>
> > "What is the purpose of your wheels", indeed. You want rock crushers?
> > Components are widely available.
>
> Not so much. 48 hole components have fallen by the wayside; many of
> the commonest up-to-date parts are available in 32 hole only rather
> than 36 hole as in the past. Consumers being willing to play along
> with (and even pay more for) manufacturers' rush towards cheapness has
> exacted casualties.
Your definition of rock crusher is different from mine.
The old 36f/40r combination went away, back in the 70's when I got
started. Later, the 36h standard went away in favor of 32h, which also
survived the change from tubular to clincher.
"Rims are getting better" would be one guess as to why.
> > TT wheels? Same deal, more likely as
> > a prebuilt wheel, and probably more expensive, especially if you want
> > both aero and light. "How fast do you want to spend?"
>
> You can always get what you want if there is no limit to how much you
> are willing and able to spend for it. The problem thus created is at
> the other end of the market, where inexpensive, rugged field-grade
> equipment disappears because the most profitable [suggestible]
> fraction of the market has been snookered into buying something less
> for more money.
I'm far from the cutting edge of the market and I can get what I want,
at reasonable prices.
You could guess that upper-end parts have driven lower-end parts out
of the catalogs, but that's just a guess. In the scramble to be
competitive in a fairly small world market, I'd think manufacturers
would take profit wherever they could.
One reflection of this is the availability of what I would call low
and mid-priced pre-built wheels; they're not all priced into the
stratosphere by any means.
"Suggestible" and "snookered" are pejorative rhetorical devices.
People who ride for sport and who, due to being successful in life,
can afford high-end components are not, I would suggest, either
"stupid" or "gullible" when it comes to "buying something less (as in
less weight and/or wind resistance?) for more".
--D-y
thirty-six
I am under the impression that stainless is generally regarded as a
poor material selection when the component can so easily be viewed all
around for degradation due to corrosion. Stainless also corrodes andf
it would not surprise me that its fatigue resistance is lower than the
alternatives sucha s those used by Berg where the magnitude of stress
variation be rather high on 17swg spokes. Corrosion was easily kept
in check with the magic zinc galvanised spokes by rubbing them with a
dry cloth so they shone like silver. Zinc plating in naturally self
healing and may reduce the risk of crack initiation, (I've never
checked this, but a soft surface makes sense).
thirty-six
> Ben C (who?) wrote:
> >>>>> I have a set of Areoheads based on a set of Dura Ace hubs with
> >>>>> the 18/24 combination.
> >>>>> Great wheels if you consider them race day only. I normally use
> >>>>> them for Criterium racing and longer/hillier sportifs.
> >>>>> I have had a couple of problems though, just the rear rim
> >>>>> hitting a pothole and have just recently replaced the front due
> >>>>> to cracking around the nipples.
> >>>>> Considering the front was 2 years old and had not even needed a
> >>>>> truing during this time leads me to think I hit something but
> >>>>> did not notice it at the time.
> >>>> I think the assessment of wheel durability is misplaced. When I
> >>>> consider the many miles on unpaved or cobble roads that my wheels
> >>>> have crossed in the more than 30 years (since I wrote "the
> >>>> or so, are still working well with their 36 spoke Campagnolo
> >>>> RECORD hubs.
> >>>> OH! but they aren't as light as CF wheels are as aerodynamic as
> >>>> 18 spoke wheels. I can only ask, "What is the goal of your
> >>>> wheels?" I think I made clear what causes fatigue failures and
> >>>> how these stresses are avoided by stress relieving wheels after
> >>>> tensioning.
> >>> If that were true, then why wouldn't it work for 24 or 18 spoke
> >>> wheels?
> >> For the same reason four steel spoked wheels don't work. Load
> >> concentration is too great at the few spokes that there are. If
> >> you look at the load diagrams in "the Bicycle Wheel" you'll notice
> >> that a 18-spoke wheel will have its entire load on essentially one
> >> spoke instead of four or more.
> > spokes in a 36H wheel are in places within 25% of their yield
> > stress?
>
> THE RIM! Get the message. Spokes can be made to support great loads,
> but rims crack and that is the subject of this thread. Stop the
> mis-attributions and out of context depictions.
>
> Jobst Brandt
I thought that was a fine place for you to bring up the REMA man and
his black truck, did he wear sunglasses, inside?
John Dacey
>I'd be more convinced of the perfection of 36-spoke wheels front and
>rear if a few points were addressed.
>
"Thirty-six spokes will last all eternity!"
So goes Jobst's emphatic, dogmatic claim.
When lesser-spoked wheels develop infirmity
You've got no grounds on which to complain.
-------------------------------
John Dacey
Business Cycles, Miami, Florida
Since 1983
Our catalog of track equipment: online since 1996
http://businesscycles.com
-------------------------------
Frank Krygowski
> On Nov 7, 9:09 am, Frank Krygowski <frkry...@gmail.com> wrote:
>
> > IOW, the total theoretical benefit is not very great.
>
> Yes, by all means. Let's wipe away any thought of technical discussion
> because one person's opinion chooses to "skip the details" and thereby
> deem any changes (improvements OR dead ends) unworthy.
In _Scientific American_, back in 1983, there was an article that
examined the benefits of different approaches to bike speed. See
http://tris.trb.org/view.aspx?id=196924
That's where I got the idea to ask about "vaporware" wheels. That SA
article included a table showing, among other things, that removing
all the air drag and weight of the entire bike (a massless, dragless
bike) didn't give as much benefit on level ground as using a low-tech
Easy Racer recumbent.
Anyone who understands numbers can easily see that the great bulk of
the resistance (weight or air drag) is the rider himself. If removing
all the bike's drag doesn't make you as fast as an Easy Racer, what
will you accomplish by removing a couple more spokes?
If you want to spend your money on stuff that tends to be less
reliable, certainly much harder to repair when it fails, and of course
much more expensive, well heck, go for it! (I have a friend who just
bought a carbon fiber hood for his sports car. I'm sure he gets great
satisfaction when he drives that thing on his morning commute.) As
with a lot of the issues we talk about, I'm not trying to forbid your
choice. But I am trying to apply a little science to the discussion.
- Frank Krygowski
Steve Sr.
<DirtR...@aol.com> wrote:
>On Nov 6, 12:53 pm, Steve Sr. <Nos...@nospam.com> wrote:
>> The hubs are radial in the front and radial/3 cross in the
>> rear if that matters.
>
>24H, 3x? Does not seem likely.
>
>DR
Correct! I just went to the closet in the other room to look. They are
actually 2X with linear pull spokes.
Steve
Steve Sr.
<dusto...@mac.com> wrote:
>On Nov 4, 6:37�pm, Steve Sr. <Nos...@nospam.com> wrote:
>
>> I am considering rebuilding a set of wheels that had Alex 20/24 hole
>> rims. They went about 5K miles before the spokes started to pull
>> thorough the rims.
>>
>> I am considering using these hubs and Velocity Aerohead and Aerohead
>> O/C rims but am wondering about the durability because of my previous
>> experience with the Alex rims.
>>
>> I currently have a set of these Velocity rims but in 32 hole
>> configuration that have been flawless for the past 10K miles.
>>
>> BTW, I only weigh about 160 pounds.
>
>If you haven't already:
>
><http://www.sheldonbrown.com/rinard/spocalc.htm>
>
>Your rims and the Velocity rims are probably in there so you can see
>what spoke lengths you're dealing with.
>
>Here are the Deep V's, if you haven't looked at the online USA catalog
>yet:
><http://www.velocityusa.com/default.asp?contentID=583>
>
>I wouldn't pretend to know what a 160lb. rider could get away with,
>IRT Aerohead v. Deep V's. The Deep V's are strong enough to be a
>favored tandem rim and recommended, as you have seen from at least one
>expert here, also for low spoke count wheels. "Take the mass out of
>the spokes, put it in the rim", so to speak, and gain an aero
>advantage from fewer spokes, if not much "aero gain" from a 30mm-deep
>rim.
>
>At well over 200lbs, I've had excellent results from 32 and 36h
>Velocity Aerohead and Aerohead OC (rear) rims with the exception of
>one machined-sidewall OC rear, which gave up the ghost very early,
>probably due to over-machining which thinned the sidewall to extreme.
>It cracked out in typical fashion for worn rims that have seen a lot
>of brake application, the sidewall parting from the "spoke bed". So,
>I'd go with the non-machined sidewall variety, which will be a little
>stronger and last longer, whichever rim you look at.
>BTW: Those OC's have built two of the strongest rear wheels I've had
>so far, judging by staying true.
>
>I don't know what kind of hubs you have but their condition would
>figure into this equation, too. Even given low milage and "event"
>status, meaning "not used much in the rain", I would guess. If they're
>serviceable, I'd get them inspected and serviced, if they're not
>heavily worn, for starters.
The existing hubs are sealed bearing in very good condition. This is
my main motivation for reusing them. This time with better rims.
Steve
>
>Noting, the old Campy Shamal wheels (40-41mm deep), at least in the 16-
>spoke version, front and rear, had a reputation for good service. The
>12-spoke Shamals seemed to be known for spoke breakage but the 16'ers
>were good. I have a set of 16's, have put some miles on them with no
>problems, including no spoke pull-through, even without ferrules. Not
>dicey in strong winds for a heavy rider, IME.
>--D-y
DirtRoadie
> On Sat, 6 Nov 2010 16:12:11 -0700 (PDT), DirtRoadie
>
> >On Nov 6, 12:53 pm, Steve Sr. <Nos...@nospam.com> wrote:
> >> The hubs are radial in the front and radial/3 cross in the
> >> rear if that matters.
>
> >24H, 3x? Does not seem likely.
>
> actually 2X with linear pull spokes.
Yes, there is a point where more "crosses" means silly spoke angle at
the hub (below tangent). In simple terms if "#Holes"/"crossX" <= 8
then the spoke pattern is suspect.
DR
Barry
> or less, stress for the rear wheel. It took some time, but Keith Bontrager
> did manage to explain to me why it was the lower-gear strong rider who was
> far more prone to spoke & rim failure than a guy like Jobst using his
> massively-huge (compared to most mortals) gears when climbing. Consider an
> overpowered motorcycle that can break a chain in 1st gear. It would never
> happen in a taller gear. Peak loads are much higher for the low-gear guy
> than the high-gear guy, and it's the loading/unloading cycles that kill
> things.
I'd like to see a detailed explanation, because it doesn't seem right to me.
The motorcycle chain example was mentioned here a while ago, and I still don't
think it's relevant. First, the chain situation for a motorcycle is a lot
different from a bicycle. Second, we're talking about wheels, not chains.
Chain tension equals power divided by chain speed: T = P/v. The highest
tension occurs with the combination of high power and low chain speed. A
motorcycle has a single rear sprocket, with the transmission upstream, so
chain speed is directly proportional to motorcycle speed, regardless of gear.
So to get low chain speed, you have to go slow. But to get high power, the
engine needs high RPM, and this combination of low motorcycle speed and high
RPM obviously means low gear. That's why it's easiest to break a motorcycle
chain in low gear.
A bicycle with a rear derailler and multiple sprockets is different. For a
given road speed, the chain speed will be proportional to the sprocket size.
For a given power and road speed (like climbing a long, steady hill), average
chain tension will be inversely proportional to rear sprocket size. In
addition, unlike the motorcycle engine, which can produce high power only at
high RPM, we can produce pretty close to maximum steady power over a wide
range of cadence. So we can have high power, low chain speed, and high chain
tension without necessarily being in a very low gear. I agree that it's
probably peak load, not average, that's important to component failure, but it
seems to me that a higher cadence will produce steadier power output, and
lower power peaks, especially if the higher cadence lets you avoid standing.
Maximum power for a few seconds (sprinting) will be at a high cadence, but
that's different than talking about pedaling style while climbing.
Concerning wheels, the torque applied to the rim equals the power divided by
the rotational speed of the wheel. For a given power and bicycle speed, the
average torque on the wheel should be independent of gearing or cadence. So
wheel failure should be more likely with whichever pedaling style produces
higher power peaks.
I though that Bicycling Science would have something about the variation of
power during the pedal stroke, and how peak instantaneous power depends on
cadence, but I couldn't find anything relevant.
DirtRoadie
> As
> with a lot of the issues we talk about, I'm not trying to forbid your
> choice. But I am trying to apply a little science to the discussion.
Yo- Frank buddy!
You are confusing YOUR opinion with science (or trying to ride on the
coattails of science).
I realize you like to hear yourself preach and that you are a devoted
follower of your position.
However, your mind is made up about what YOU need. So be it. I have no
intention of challenging your religion. Let me repeat that- I have no
intention of challenging your religion. You know what YOU want and/or
(think) you need. Not a problem.
I am in the market for a new (automotive) vehicle. So, since your
opinions are objective and unassailable, please tell me:
Should I be looking for style or value? 2 door, 4 door, station
wagon, SUV, van, mini van or pickup? Sports coupe or sedan? 4, 6 or
8 cylinder? Manual or automatic transmission? Do I need 4-wheel
drive? Is a GPS navigation system important to me? Should I focus on
fuel economy, passenger/load/towing capacity or crashworthiness? Which
is more important, city MPG or highway mpg Would a convertible suit
me?
Vinyl or leather interior? What is my budget range? Geez, what color
should it be?
I thought I had a handle on these things for MY purposes, but I am
undoubtedly wrong based upon YOUR conclusions.
And after you have answered those questions please also tell me what
wheels I need to buy for my bicycle the next time that issue raises.
Or might I even consider building the wheels as I have for ALL my
bikes for many years? Tandem, MTB, road, multi-purpose included.
But before you jump in with your information, first tell which of my
bikes we are referring to and what wheel characteristics you are
prescribing for me. Tell me my weight, my riding style, the tires I
use and my preferred terrain/mileage/speed for the bicycle you have
chosen. Oh, and my budget.
Just so I will know.
I would hate to rely upon a choice made based upon erroneous
assumptions- like someone else merely describing what HE thinks (or
has concluded) may be "good" or right for HIM (or what HE thinks
SCIENCE has concluded is right for him/everyone.)
As I have noted, I have no intention of challenging your religion. But
you would do well to understand that YOUR opinion is nothing more than
your opinion. Which is, colloquially, worth $.02. Even if it is based
on SCIENCE. Just so you understand, replace "science" with "the bible"
and you MAY start to understand how you sound.
DR
Tom Ace
wrote:
> Yet there is even greater variability in pedaling style that creates
> more, or less, stress for the rear wheel. It took some time, but Keith
> Bontrager did manage to explain to me why it was the lower-gear strong
> rider who was far more prone to spoke & rim failure than a guy like
> Jobst using his massively-huge (compared to most mortals) gears when
> climbing. Consider an overpowered motorcycle that can break a chain in
> 1st gear. It would never happen in a taller gear. Peak loads are much
> higher for the low-gear guy than the high-gear guy, and it's the
> loading/unloading cycles that kill things. Jobst gives far too little
> credit for his wheel longevity to his unusual riding style. (I still
> didn't believe Keith; it just seems wrong to believe that the big gear
> masher isn't doing his best to destroy things, but empirical evidence
> tells me he's absolutely correct, at least for wheels. We see the same
> situation for frames as well, but it's not so obvious because larger
> frames are significantly more affected by structural issues (since
> builders don't usually "scale" well when they go from smaller to larger
> frames), and Jobst's frame size is kind off the chart. He's going to
> break them just because he's very tall and very strong. Maybe he'd break
> them even faster if he used lower gears? I don't know. Jobst is special.
> :-)
If you can, please describe the empirical evidence that you say bears
this out. I wonder if all else is equal, and if differences you are
seeing
in wheel longevity have anything to do with peakiness of drive torque.
As Jobst has pointed out, the changes in spoke tension due to drive
torque are smaller than the changes due to cyclic unloading when
spokes are at the bottom of the wheel. I have to ask whether other
aspects of riding habits (terrain, or the rider's body movements,
or ...)
are making the difference rather than drive torque.
Tom Ace
carl...@comcast.net
<andre...@aol.com> wrote:
>On Nov 6, 11:53 am, Steve Sr. <Nos...@nospam.com> wrote:
>> On Thu, 04 Nov 2010 19:37:31 -0400, Steve Sr. <Nos...@nospam.com>
>> wrote:
>>
>>
>>
>> >Hello,
>>
>> >I am considering rebuilding a set of wheels that had Alex 20/24 hole
>> >rims. They went about 5K miles before the spokes started to pull
>> >thorough the rims.
>>
>> >I am considering using these hubs and Velocity Aerohead and Aerohead
>> >O/C rims but am wondering about the durability because of my previous
>> >experience with the Alex rims.
>>
>> >I currently have a set of these Velocity rims but in 32 hole
>> >configuration that have been flawless for the past 10K miles.
>>
>> >BTW, I only weigh about 160 pounds.
>>
>> >Thanks,
>>
>> >Steve
>>
>> Thanks for everyones input. I agree with Andrew that the spoke count
>> is on low side for durability.
>>
>> As I mentioned, the original rims started to fail at about 5K miles
>> and were replaced under warranty. The new set had about 5K miles on
>> them when a minor crash took out the front wheel. Since I have 5K on
>> the rear which is where the original failed I was planning on
>> rebuilding both to be done with it. Were these over tensioned? I have
>> no way of knowing.
>>
>> I am primarily looking at rebuilding these as a secondary/spare set
>> and not wanting to break the bank doing it. This includes reusing the
>> spokes if at all possible. This is one reason why I was looking at the
>> Aerohead. I believe that the ERD was close enough to use the old
>> spokes. The hubs are radial in the front and radial/3 cross in the
>> rear if that matters.
>>
>> Steve
>
>If you wish to carry an elephant on your bike:
>http://bikeisland.com/cgi-bin/BKTK_STOR20.cgi?Action=Details&ProdID=1776
Dear Andres,
http://img.moonbuggy.org/elephant-tricycle/
http://www.gettyimages.com/detail/HC3372-001/Hulton-Archive
Cheers,
Carl Fogel
Frank Krygowski
> On Nov 7, 6:05 pm, Frank Krygowski <frkry...@gmail.com> wrote:
>
> > As
> > with a lot of the issues we talk about, I'm not trying to forbid your
> > choice. But I am trying to apply a little science to the discussion.
> And after you have answered those questions please also tell me what
> wheels I need to buy for my bicycle the next time that issue raises.
DR: There's no need to go into much detail. It's easy to tell what
wheels you need.
You need the lightest, most aerodynamic wheels you can possibly find.
For you, durability is no concern. Availability of repair parts (like
proprietary spokes and nipples) is no concern. Compatibility with any
other part of your bike is no concern. Actual performance difference
in any given situation is no concern, although you do need to have
numbers to tell your friends. (Claimed drag reduction ought to
suffice.) Of course, price is no concern, as long as they're suitably
expensive.
You NEED the wheels with the highest zoot factor, the ones that match
the flashiest advertisements, and that match those used by the teams
with the biggest budgets. And the following year, when the ads and
the sponsorships change, you'll NEED a new set of wheels.
Hope this helps. Enjoy!
- Frank Krygowski
Ben C
>>>>> I think the assessment of wheel durability is misplaced. When I
>>>>> consider the many miles on unpaved or cobble roads that my wheels
>>>>> have crossed in the more than 30 years (since I wrote "the
>>>>> Bicycle Wheel"), the same MA-2 rims, that even had a pinch flat
>>>>> or so, are still working well with their 36 spoke Campagnolo
>>>>> RECORD hubs.
>
>>>>> OH! but they aren't as light as CF wheels are as aerodynamic as
>>>>> 18 spoke wheels. I can only ask, "What is the goal of your
>>>>> wheels?" I think I made clear what causes fatigue failures and
>>>>> how these stresses are avoided by stress relieving wheels after
>>>>> tensioning.
>
>>>> If that were true, then why wouldn't it work for 24 or 18 spoke
>>>> wheels?
>
>>> For the same reason four steel spoked wheels don't work. Load
>>> concentration is too great at the few spokes that there are. If
>>> you look at the load diagrams in "the Bicycle Wheel" you'll notice
>>> that a 18-spoke wheel will have its entire load on essentially one
>>> spoke instead of four or more.
>
>> Why should that matter? Are you saying that even "stress-relieved"
>> spokes in a 36H wheel are in places within 25% of their yield
>> stress?
>
> THE RIM! Get the message. Spokes can be made to support great loads,
> but rims crack and that is the subject of this thread. Stop the
> mis-attributions and out of context depictions.
Well, you wrote:
>>>>> OH! but they aren't as light as CF wheels are as aerodynamic as
>>>>> 18 spoke wheels. I can only ask, "What is the goal of your
>>>>> wheels?" I think I made clear what causes fatigue failures and
>>>>> how these stresses are avoided by stress relieving wheels after
>>>>> tensioning.
So if you weren't talking about spokes, are you now claiming that "stress
relieving" stops the rim fatiguing?!!
Why not I suppose. In for a penny in for a pound.
Anyway, I suspect you just got your catechisms jumbled up. But the point
I now realize you were trying to make, which is that wheels with fewer
spokes need higher spoke tension, which wrecks the rim, is not a problem
in reality. If everything else were equal, that would be true, but it's
not. Modern rims are deeper section and stiffer, and need no more
(possibly less) tension in each of their 18 or 24 spokes than the MA-2
needed in its 36.
Michael Press
<67929a4b-c6ac-41c1...@a30g2000vbt.googlegroups.com>,
Chalo <chalo....@gmail.com> wrote:
> Ed wrote:
> >
> > I am not convinced an eyelet is goint to solve things unless you get
> > one that transfers the force to the inner wall of the rim - I don't
> > think they make those any more.
>
> A single eyelet (grommet) serves two valuable purposes: It provides a
> better bearing surface for the spoke nipple head, and it helps prevent
> galling damage at the drilling from initiating cracks into the rim
> extrusion.
>
> Double eyelets (sockets) are still offered by Mavic, Rigida, and Alex
> on a few models. Whether they actually transfer any load to the
> internal wall of the rim depends on the specifics of the socket and
> the rim extrusion and manufacturing tolerances. On modern deep and
> semi-deep section rims, sockets offer the benefit of keeping nipples
> from going astray within the rim channel while the wheel is being
> laced.
The CR18 has eyelets. It does not have sockets
but they are overbuilt with doubled walls that
serve for sockets.
--
Michael Press
Tom Sherman °_°
[1] <http://www.sun-ringle.com/bmx/rims/cr-18/>,
<http://www.sun-ringle.com/product-vault/road-rims/cr18-700c-29er/>.
kolldata
> >>>> 18/24 combination.
>
> >>>> Great wheels if you consider them race day only. I normally use
> >>>> them for Criterium racing and longer/hillier sportifs.
>
> >>>> I have had a couple of problems though, just the rear rim hitting
> >>>> a pothole and have just recently replaced the front due to
> >>>> cracking around the nipples.
>
> >>>> Considering the front was 2 years old and had not even needed a
> >>>> truing during this time leads me to think I hit something but did
> >>>> not notice it at the time.
>
> >>> consider the many miles on unpaved or cobble roads that my wheels
> >>> have crossed in the more than 30 years (since I wrote "the Bicycle
> >>> still working well with their 36 spoke Campagnolo RECORD hubs.
>
> >>> OH! but they aren't as light as CF wheels are as aerodynamic as 18
> >>> spoke wheels. I can only ask, "What is the goal of your wheels?"
> >>> I think I made clear what causes fatigue failures and how these
> >>> stresses are avoided by stress relieving wheels after tensioning.
>
> >> If that were true, then why wouldn't it work for 24 or 18 spoke wheels?
>
> >For the same reason four steel spoked wheels don't work. Load
> >concentration is too great at the few spokes that there are. If you
> >look at the load diagrams in "the Bicycle Wheel" you'll notice that a
> >18-spoke wheel will have its entire load on essentially one spoke
> >instead of four or more.
>
>
> >http://www.avocet.com/wheelbook/wheelbook.htmlq
> >http://tinyurl.com/22v535
>
>
> Dear Jobst,
>
> Can you give us some load calculations or diagrams on 24 and 18 spoke
> figures?
>
>
> Carl Fogel- Hide quoted text -
>
> - Show quoted text -
no scatter diagrams but I have asked various LBS types
receiving' whoa you wouldn't beleive it's' as response.
At first sins of wear, install Ti washers. Lube brake surface with
CRC Rubbah Dressing. Lube hub's spoke holes with spokes with Finish
Line Dry Lube or Pedro's 2.0
dusto...@mac.com
Wow. What a tirade.
<http://drivewayseries.com.aspx2.dotnetpanel.net/Home/tabid/103/
Default.aspx>
Hey Frank, instead of sticking your tongue out and making raspberries:
You could look at the 40+ sponsors, local and national, on the home
page.
You could go into "info", and see the schedule and payouts.
You could go to "results" and see at least 12 teams participating on a
regular basis.
You could go to "course" and see at least two of the road courses, and
note the 'cross courses. Yes, there's more than just a Thursday
Nighter crit going on here.
You could go to "clinics" and see Paul Hurdlow's of DLA Piper (only
one of the doctor/lawyer/indian chiefs who races there and elsewhere)
sponsorship statement.
You could go to "sponsorship" and see various items of interest,
including the fact that the Driveway Series had approx. 7000
participants in 2010, and the fact that the "average" participant has
a bachelor's degree and a professional occupation.
Whoops. There's a functioning racing culture where successful
professional people race their bicycles and can afford to buy good
tools for the job. Lighter, more aero, faster, sure, but the
discussions I hear IRT "wheels" center around durability, function
being assumed and/or documented and not only through advertising
claims, but real-world comparison tests. Whoops again!
Earlier in this thread, I posted some modeling and real road results
on aero wheels you seem to have missed, too. (One more time): Front
TriSpoke and disc rear yielded 1-1/2 - 2 minutes faster over 40k at
racing speeds, compared to box-section, high spoke count wheels.
Figure less effect for spoked wheels, say half? OK, 0:45 - 1:00 faster
for 40k.
For people competing at whatever level, those are significant
differences.
--D-y
Dan O
Smarmarific!
> <http://drivewayseries.com.aspx2.dotnetpanel.net/Home/tabid/103/
> Default.aspx>
>
"Click here to download the plugin."
Did he say, "How much difference would a rider notice if he rode
wheels that had zero mass and zero aerodynamic drag? My guess
is, not much." (?) Really, rider notice riding wheels with zero
mass??
Sounds spooky, actually.
Ron Ruff
> Did you check the tension on them? Alex rims are made from a strong
> alloy. Tension that's enough to crack them is enough to destroy most
> other similar rims, regardless of brand.
A strong alloy is not necessarily good. See "stress corrosion
cracking".
DirtRoadie
Actually it does not. But that was expected and was your intent. In
reliance upon the wheels that YOU slog along on during your commute
you apparently think I must need something that is just the opposite,
literally for the sake of argument. You bundle in a bit of personal
attack with your disdain for expensive wheels and/or racers and the
veiled implication that you are far too smart to spend any money on
"boutique" wheels while I am not. That doesn't tell me anything about
wheels, but it tells me about YOU, information which is of no value to
me whatsoever. Somewhere in your "scientific" approach you forgot the
take the "U" factor out of the equation.
Your wheel suggestion might be suitable for a TT bike but I have no
bike dedicated to that pursuit. Indeed, the next wheel I am likely to
BUILD will be a rim replacement for an existing mountain bike wheel.
I have no idea why you found it necessary to reference useless (in
this context) data about aerodynamics. Ah yes, science! Got to throw
in a pinch of that even if it is utterly irrelevant. Let's not begin
to consider actually APPLYING objective information accurately. If you
only have a hammer be sure to try to apply only a "nail" analysis to
any review.
Interestingly, objective information from this thread (clearly not
from you) has led me to a rim which I was previously unaware of and
which is has characteristics I have been seeking or longing for
without success. So there ARE folks here providing useful info.
Anyhow thanks for accepting my invitation to demonstrate unequivocally
how much you like to preach and how little you care for objectivity,
despite your claim otherwise.
DR
Ron Ruff
> I though that Bicycling Science would have something about the variation of
> power during the pedal stroke, and how peak instantaneous power depends on
> cadence, but I couldn't find anything relevant.
Peak = double the average is a good starting point. Also if you do the
calculations, you'll find that heavy and strong riders on steep grades
in a low gear are the "worst case" scenario for rear wheel torque.
Peter Cole
I think the worst case for spokes is when riders "toss" a bike side to
side during sprints. You get big lateral loads.
DirtRoadie
I have no idea if that is true or not and I have not seen any analysis
of deeper stiffer rims from anyone (Jobst included).
But a deeper and/or "aero" rim can also have the benefit of a spoke
bed that is more strongly reinforced than that of a classic box
section.
See example here of the rims mentioned by the OP:
http://www.universalcycles.com/images//products/medium/7311.jpg
DR
Ron Ruff
> But a deeper and/or "aero" rim can also have the benefit of a spoke
> bed that is more strongly reinforced than that of a classic box
> section.
That is certainly true... and some alloys are more resistant to
cracking as well.
Frank Krygowski
Not a tirade at all! (I think to qualify as "tirade," a person would
have to be at least frowning while writing. I was far from that!)
My point was just this: There are people who's enjoyment of cycling
is tied very closely to their perception of their equipment's
sophistication. It's like the friend I mentioned who bought the ten
pound carbon fiber hood for the sports car he drives to work. He was
obviously proud of it, and doubtlessly derived pleasure out of driving
a car with a carbon fiber hood.
If a person needs a carbon fiber hood (or a wheel with a spoke count
that's lower than the next guy) to feel good about his ride, what can
I say? He needs it, so he buys it. Again, I'm not trying to forbid
any choices.
Now, if we're actually talking about measurable benefits (whether less
time making it home from work, able to stay with buddies on a
recreational ride, consistently better placement in amateur road
races, better chance at making a pro team, measurably better time
trial results, a Tour de France stage win, a new world hour record or
whatever), well it's reasonable to examine numbers on how much any
purported improvement is _really_ worth.
It's my contention that a lot of the touted improvements are actually
negligible. Many are not worth precisely zero, and not all are
typically negligible, but I think a lot of them are. In fact, I think
some of the claimed performance gains would be significant only for a
world hour attempt. Yep, not even a stage win attempt.
Not that I was ever in that universe of athletic performance - but
there have been times I've played with aero improvements to my bike,
back when I tried to go fast. For time trialing, I'm sure the aero
bars definitely helped. The rear wheel disk spoke covers probably
helped, although I couldn't really feel it, and I certainly couldn't
find evidence it did. But things like going from ancient exposed
brake cables to aero hidden cables? Or an aero water bottle? Moving
the pump to a more aero position, and other detail efforts? Just not
enough difference to detect.
To give a further example: I was on a club ride a week ago that was
supposed to be a fairly well-attended ride, but ended up being tiny,
just me on my touring bike and two guys who were a racer and an ex-
racer, both 15 to 25 years younger than me. They could have ridden
away from me any time they wanted to.
Now, one guy was on a Cervelo. Was that why he was faster than me?
Or to put it more practically, if I bought a Cervelo, would I have
been able to keep up with him? Hell no, not me, not you, and not 99%
of the people who are tempted by performance parts, despite the ads
and claims, and despite "all the racers use them."
Similarly, chewing Dentyne gum isn't _really_ going to cause chicks to
think you're sexy. That would be true whether or not all the top male
heartthrobs chew Dentyne or not.
- Frank Krygowski
thirty-six
yes!
thirty-six
The most obvious thing is when moving from 36 to 24 is to go up a
gauge in spokes, so for a bombproof 36, I like 15swg so for a
bombproof 24 14swg would be appropriate . Only those selecting less
than 28 spokes are not looking for bombproof wheels, so 15 or 16swg is
probably appropriate, if the things are nicely double tied and
soldered, else leave it at 15swg (or even 14swg if skinny spokes
havn't caught on in your group).
Mike Jacoubowsky
news:4d950402-2bc6-478a...@29g2000prb.googlegroups.com...
On Nov 7, 10:10 am, "Mike Jacoubowsky" <Mi...@ChainReaction.com>
wrote:
> Yet there is even greater variability in pedaling style that creates
> more, or less, stress for the rear wheel. It took some time, but Keith
> Bontrager did manage to explain to me why it was the lower-gear strong
> rider who was far more prone to spoke & rim failure than a guy like
> Jobst using his massively-huge (compared to most mortals) gears when
> climbing. Consider an overpowered motorcycle that can break a chain in
> 1st gear. It would never happen in a taller gear. Peak loads are much
> higher for the low-gear guy than the high-gear guy, and it's the
> loading/unloading cycles that kill things. Jobst gives far too little
> credit for his wheel longevity to his unusual riding style. (I still
> didn't believe Keith; it just seems wrong to believe that the big gear
> masher isn't doing his best to destroy things, but empirical evidence
> tells me he's absolutely correct, at least for wheels. We see the same
> situation for frames as well, but it's not so obvious because larger
> frames are significantly more affected by structural issues (since
> builders don't usually "scale" well when they go from smaller to larger
> frames), and Jobst's frame size is kind off the chart. He's going to
> break them just because he's very tall and very strong. Maybe he'd break
> them even faster if he used lower gears? I don't know. Jobst is special.
> :-)
========
If you can, please describe the empirical evidence that you say bears
this out. I wonder if all else is equal, and if differences you are
seeing
in wheel longevity have anything to do with peakiness of drive torque.
As Jobst has pointed out, the changes in spoke tension due to drive
torque are smaller than the changes due to cyclic unloading when
spokes are at the bottom of the wheel. I have to ask whether other
aspects of riding habits (terrain, or the rider's body movements,
or ...)
are making the difference rather than drive torque.
Tom Ace
=========
To the extent that the loading/unloading cycle is determined by drive forces
and not which spoke is on the ground, the lower gear person is putting the
wheel through more cycles than the higher gear person. That one's obvious.
The rest is stuff for people schooled in the physics of what's going on to
figure out.
The empircal evidence comes from observations of rear wheel durability.
We're talking many thousands over many years, so it's not a case of drawing
conclusions from a small sample size to justify a hypothesis. It worked the
other way around; we were trying to figure out why low-spoke-count rear
wheels were surviving fine with some big & strong riders and failing with
some much-lighter-weight folk. It simply wasn't making sense. Now, it does.
--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA
James
> On Nov 7, 11:45 am, DirtRoadie <DirtRoa...@aol.com> wrote:
>
> > On Nov 7, 9:09 am, Frank Krygowski <frkry...@gmail.com> wrote:
>
> > > IOW, the total theoretical benefit is not very great.
>
> > Yes, by all means. Let's wipe away any thought of technical discussion
> > because one person's opinion chooses to "skip the details" and thereby
> > deem any changes (improvements OR dead ends) unworthy.
>
> In _Scientific American_, back in 1983, there was an article that
> That's where I got the idea to ask about "vaporware" wheels. That SA
> article included a table showing, among other things, that removing
> all the air drag and weight of the entire bike (a massless, dragless
> bike) didn't give as much benefit on level ground as using a low-tech
> Easy Racer recumbent.
>
> Anyone who understands numbers can easily see that the great bulk of
> the resistance (weight or air drag) is the rider himself. If removing
> all the bike's drag doesn't make you as fast as an Easy Racer, what
> will you accomplish by removing a couple more spokes?
I don't ride on flat roads or at constant velocity.
I think there was an old saying that goes something like "each pound
added to the wheels is equal to two added to the frame."
The mass of wheels does matter to some, not so much to others.
JS.
James
One tool short of a tool belt.
Light, aerodynamic and durable. It is possible. Many people have
learned that it is. You haven't.
JS.
James
Even if you make 10 tiny improvements that in total give you an extra
1% you have a better chance in a race.
For a training ride, who cares. Use the heaviest heap of dung you can
keep up on.
JS.
David Scheidt
There's an old saying "if weighs the same as a duck, it's a witch".
Makes just as much sense.
--
sig 4
James
> :I think there was an old saying that goes something like "each pound
> :added to the wheels is equal to two added to the frame."
>
> There's an old saying "if weighs the same as a duck, it's a witch".
> Makes just as much sense.
Google it. You might find it makes even more sense.
JS.
DirtRoadie
> In rec.bicycles.tech James <james.e.stew...@gmail.com> wrote:
> :I think there was an old saying that goes something like "each pound
> :added to the wheels is equal to two added to the frame."
>
> There's an old saying "if weighs the same as a duck, it's a witch".
> Makes just as much sense.
The bicycle "saying" has some basis in fact in that when accelerating
a bicycle it not only necessary to apply f=ma to the mass of the
entire bike but it is also necessary to get the mass of the wheels
rotating. So under normal circumstances the mass of the wheels does
actually come into play twice during acceleration.
So in the most general sense, the rule of thumb reflects reality, if
not necessarily being mathematically precise.
DR
Tom Ace
> The bicycle "saying" has some basis in fact in that when accelerating
> a bicycle it not only necessary to apply f=ma to the mass of the
> entire bike but it is also necessary to get the mass of the wheels
> rotating. So under normal circumstances the mass of the wheels does
> actually come into play twice during acceleration.
> So in the most general sense, the rule of thumb reflects reality, if
> not necessarily being mathematically precise.
If the mass is at the very edge of the wheel it's exactly 2x.
Mass at (x times the wheel's radius) from the axis
counts (1 + x^2) as much. E.g,, mass halfway
between the axis and the edge counts 1.25 as
much as non-rotating mass.
Tom Ace
Barry
> and not which spoke is on the ground, the lower gear person is putting the
> wheel through more cycles than the higher gear person. That one's obvious.
That would be true for the crank, and for the chain in some cases, but not for
the wheel. The low-gear rider might crank faster, but if he produces the same
power and climbs the hill at the same speed as the high-gear rider, both
wheels turn at the same speed (otherwise one rider would go faster) and both
rear hubs get the same torque from the chain.
> The rest is stuff for people schooled in the physics of what's going on to
> figure out.
That's what I'm trying to do, and it seems to me that the key effect is the
variation of power during the pedal stroke, and how this depends on cadence.
I don't understand how spinning at a higher cadence would generally correlate
with higher instantaneous power peaks.
Barry
>> power during the pedal stroke, and how peak instantaneous power depends on
>> cadence, but I couldn't find anything relevant.
> Peak = double the average is a good starting point.
Independent of cadence?
> Also if you do the
> calculations, you'll find that heavy and strong riders on steep grades
> in a low gear are the "worst case" scenario for rear wheel torque.
I agree with heavy, strong, and steep, but not with the low gear part. For a
given power, slope, and climbing speed, why would low gear mean higher rear
wheel torque?
Ben C
> On Nov 8, 1:41�am, Ben C <spams...@spam.eggs> wrote:
>> Anyway, I suspect you just got your catechisms jumbled up. But the point
>> I now realize you were trying to make, which is that wheels with fewer
>> spokes need higher spoke tension, which wrecks the rim, is not a problem
>> in reality. If everything else were equal, that would be true, but it's
>> not. Modern rims are deeper section and stiffer, and need no more
>> (possibly less) tension in each of their 18 or 24 spokes than the MA-2
>> needed in its 36.
>
> I have no idea if that is true or not and I have not seen any analysis
> of deeper stiffer rims from anyone (Jobst included).
We had this discussion a while ago, and someone looked up the spoke
tensions Mavic recommend for various wheels of theirs. They were all
somewhere around 900 to 1000N, regardless of the number of spokes.
According to Jobst, you would need around 4x the tension for 18 spokes
rather than 36 since the wheel may be "supported by only 1 spoke instead
of by 4".
But 4000N would be far too much-- if the nipple threads didn't strip the
rim would crack very soon. Jobst is probably right that if you tried to
make an 18-spoke MA-2 wheel by using every other spoke hole you would
need a lot more tension (2x or 4x? I'm not sure myself). Yet, 18 spoke
wheels, using rims intended for 18 spokes, work perfectly well, and the
reason is the rims are stiffer.
> But a deeper and/or "aero" rim can also have the benefit of a spoke
> bed that is more strongly reinforced than that of a classic box
> section.
> See example here of the rims mentioned by the OP:
> http://www.universalcycles.com/images//products/medium/7311.jpg
Yes, and they've all got deeper, even the non-aero ones, except for a
few retro products which are similar to the MA-2.
Mavic's traditional non-aero rim these days is the Open Pro which is
deeper but thinner-walled than the MA-2.
My guess is people have got better at making thin-walled extrusions so
can make a stiffer structure for similar weight, which also means you
can save a few spokes.
DirtRoadie
Lower gear would mean more ability to apply greater instantaneous
torque even if speed is relatively constant. The same thing is readily
seen when climbing with limited traction on a mountain bike. Use of a
low gear makes it MUCH easier/more likely to break the wheel loose.
In fact that's one reason why folks on single speeds find themselves
able to do climbs they could not do on multi-geared bikes.
DR