Wheel truing with dial indicators
Saltytri
truing. Also, a dish tool with a dial indicator. (No flames on this, please -
I know that some will say that this level of precision is overkill but I like
making things.) While Jobst's fine book suggests that dial indicators have
some value, I haven't found any reference that tells me what level of truing
and dish accuracy is considered acceptable. I don't have enough experience to
know by look/feel/calipers when a wheel is considered good enough so I can't
translate build quality by those more subjective standards into objective
measurement criteria. What are reasonable targets in thousanths?
jobst....@stanfordalumni.org
> are reasonable targets in thousandths?
Depending on what sort of brakes and pad clearance you use, lateral
alignment between +-0.005 is fine. Just remember that brake pads drag
on rear wheels anyway with dual pivot brakes because their higher
mechanical advantage demands lower brake pad clearance. For this
reason many professional riders leave the rear QR open on long climbs
and Campagnolo switched back to a single pivot 1:1 ratio caliper for
rear brakes.
These are the criteria for trueness, aside from the need for uniform
tension among spokes of the same side for rear wheels and all spokes
for front wheels. It seems to me that if you are designing tools, the
goal should already be known and the method of achieving that arrived
upon from practice. Quantifying lateral and vertical trueness is one
thing, but doing it so that it assists truing a wheel requires more
than just that. It must be practical. Reading numbers may not be as
useful to the experienced mechanic than watching an air gap between
rim and gauge point grow and shrink when the wheel is rotated. This
method has served well with good results for a long time.
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA
Shane Stanley
jobst....@stanfordalumni.org wrote:
> Depending on what sort of brakes and pad clearance you use, lateral alignment
> between +-0.005 is fine.
>
What units are you using there?
Shane Stanley
jobst....@stanfordalumni.org
>> Depending on what sort of brakes and pad clearance you use, lateral
>> alignment between +-0.005 is fine.
> What units are you using there?
Oh how clever. What else? Did you perhaps think millimeters,
nanometers, or Angstroms. This reminds me of Snap-on Tools changing
their metric wrench markings to, for instance, to 10MM instead of 10,
so the American will know it's not a 10inch end wrench, much less a
30inch on a large one. Lower case m's were not good enough either,
while English sizes were not changed to show that they are in inches.
I guess for some folks a 25x error is easy to make when measuring or
selecting tools.
jobst....@stanfordalumni.org
>> Depending on what sort of brakes and pad clearance you use, lateral
>> alignment between +-0.005 is fine.
> What units are you using there?
Oh how clever. What else? Did you perhaps think millimeters,
nanometers, or Angstroms. This reminds me of Snap-on Tools changing
their metric wrench markings to, for instance, 10MM instead of 10, so
the American will know it's not a 10inch end wrench, much less a
30inch on a large one. Lower case m's were not good enough either,
while English sizes were not changed to show that they are in inches.
I guess for some folks a 25x error is easy to make when measuring or
selecting tools.
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA
Shane Stanley
jobst....@stanfordalumni.org wrote:
> Shane Stanley writes:
>
>>> Depending on what sort of brakes and pad clearance you use, lateral
>>> alignment between +-0.005 is fine.
>>>
>> What units are you using there?
>>
> Oh how clever.
>
It wasn't particularly meant to be, although I guess one could argue that
being unsure and not asking would be dumb.
> What else? Did you perhaps think millimeters, nanometers, or Angstroms.
>
I assumed inches, but I was wondering if the answer was none of these. The
only other site I can find that mentions a value (admittedly not
specifically for a new wheel) says 1/16th of an inch, which is more than 10
times 0.005 inches. Given the disparity, I thought it not unreasonable to
check if the difference was one of units.
> I guess for some folks a 25x error is easy to make when measuring or selecting
> tools.
And I guess for some clever folks an error of judgment about a simple
question is easy to make.
Shane Stanley
Lindsay Rowlands
: I just put together a truing stand with dial indicators for radial and lateral
I aim for less than 1mm - 0.039" - which is pretty easy to achieve. I
doubt there is any real benefit in a lower figure other than some kind of
perverse satisfaction. Tyres are usually out of round to a greater extent
anyway.
I don't buy Jobst's version of brake pads rubbing on rims. Curiously, my
single pivoted bike climbs just as easily as my dual pivoted one. Sounds
like bicycle folklore.
Cheerz,
Lynzz
David Damerell
>Shane Stanley writes:
>>>Depending on what sort of brakes and pad clearance you use, lateral
>>>alignment between +-0.005 is fine.
>>What units are you using there?
>Oh how clever. What else?
Besides being snide, it'd be handy if you told us what it is that the units
obviously are. .005in seems too little - turning one nipple 1/4 turn on a
conventional 36-spoke wheel moves the rim laterally by more than an eighth
of a millimeter, and you yourself say a 1/4 turn is the minimum necessary
adjustment. .005cm is even smaller, and .005 meters is ridiculously large.
So, no, it's not just pedantry. I have no idea what the units are here;
and I thought exactly the same thing as Mr. Stanley on first reading your
articles.
--
David Damerell <dame...@chiark.greenend.org.uk> flcl?
Sergio SERVADIO
> <jobst....@stanfordalumni.org> wrote:
> >Shane Stanley writes:
> >>>Depending on what sort of brakes and pad clearance you use, lateral
> >>>alignment between +-0.005 is fine.
> >>What units are you using there?
> >Oh how clever. What else?
> Besides being snide, it'd be handy if you told us what it is that the units
> obviously are.
> So, no, it's not just pedantry. I have no idea what the units are here;
> and I thought exactly the same thing as Mr. Stanley on first reading your
> articles.
Me too, in fact.
Though I soon suspected you were only teasing about it.
Were you really?
Sergio
Pisa
MikeYankee
Seems to be about twice what I can usually achieve (depends somewhat on spoke
count and rim type), and I haven't had any problems with durability, brakes
rubbing, etc. I'm satisfied to get the lateral trueness within .25 mm by
eyeball. How does one get closer than that, especially as a slight waviness
sets in as the wheel is brought up to final tension (e.g., ~120 kgF drive-side
tension on a road wheel with 14/15 DB spokes, measured by Wheelsmith
tensiometer)?
Mike Yankee
(Address is munged to thwart spammers.
To reply, delete everything after "com".)
David Ornee
<jobst....@stanfordalumni.org> wrote in message
news:a8%3a.66701$Ik.28...@typhoon.sonic.net...
Lateral error should be <.5 mm
I suggest you get a copy of Barnett's Chapter 17 on Wheel Truing. I think
you will find that precision in tension balancing is more important than
getting extremely precise truing.
Spoke alignment, proper spoke tension, tension balancing, and stress
relieving are all covered in Jobst's book.
A quote from Wheelsmith's website at URL
http://www.wheelsmith.com/page4.html bears repeating:
"Wheelsmith's wheelbuilding philosophy emphasizes strength and durability,
and the key is high, uniform spoke tension. Spoke tension is the most
difficult and elusive aspect of wheelbuilding. It is the characteristic of
the wheel most difficult to evaluate, yet the most critical to its
performance. This approach to wheelbuilding, based on combining both art and
science, and focusing on tension rather than cosmetic trueness, was
pioneered by Wheelsmith and remains at the foundation of our process.
Cosmetic trueness can actually come at the expense of a wheel's strength
because it can result in unbalanced tension. So do not be misled by some
builders' claims about trueness, because what really matters is not how true
a wheel is now, but how true it is 1,000 miles from now."
David Ornee, Western Springs, IL
David Damerell
><jobst....@stanfordalumni.org> wrote in message
[stuff]
>relieving are all covered in Jobst's book.
I think you'll find the gentleman to whom you have replied knows what is
in Jobst's book quite well.
Per Elmsäter
So you're actually saying that a +-5 mm lateral alignment is sufficient.
--
Replace the dots to reply
Perre
David Ornee
"David Damerell" <dame...@chiark.greenend.org.uk> wrote in message
news:C5w*3t...@news.chiark.greenend.org.uk...
I was replying to the group in what I thought would be a helpful sequence.
I apologize if my input was out of order or not useful to you.
Steve Shapiro
I thought that the reason Campy went to single pivot rear was to save
weight. After all, the rear brake does not provide much stopping
power compared with the front. Further, locking up the rear is easy
and potentially dangerous with high mechanical advantage calipers.
So, the two-pivot rear caliper gives no real stopping advantage but
exacts a weight penalty.
Does anyone know why bikes are made with the right hand brake
controlling the rear wheel? Most of us are right handed and would
have better control if the right hand lever operated the front brake,
in my opinion. But I digress.
Regarding how true is true, I think it is a good question ‘cause I am
interested to see the opinion of others. It seems as if ±0.005" is a
good objective. A total swing of 0.01" easy to see without
indicators, but the difference between 0.005 and 0.006" is impossible
to know without dial indicators. I think I'll try to find some old
feeler gauges or get some shim stock just to give me an idea how true
my wheels are. While I do not think wheel wobble is terribly
important as long as the brakes don't rub, now I'm curious to see if I
can make measurements with simple tools. Why? Because it is a matter
of pride to make wheels that are very, very true. Since unusual
spoking patterns are of no real benefit, the skilled amateur can find
satisfaction with careful selection of components and meticulous
assembly as his accomplishments. I'd like to quantify (once will
probably be enough for me) just how true my home-built wheels are.
How bad is unacceptable? I do not think I'd worry about a set of
wheels with more than ±0.005 depending upon the circumstances. For
example, I'd relax my standards for a used wheel with sticky spokes /
nipples. As long as I can get even spoke tension, avoid brake
rubbing, and make the rider happy, I'd be satisfied.
Steve Shapiro
A Muzi
use, lateral
> >> alignment between +-0.005 is fine.
> Shane Stanley writes (trolls??):
> > What units are you using there?
<jobst....@stanfordalumni.org> wrote in message
news:e104a.66708$Ik.28...@typhoon.sonic.net...
> Oh how clever. What else? Did you perhaps think millimeters,
> nanometers, or Angstroms. This reminds me of Snap-on Tools changing
> their metric wrench markings to, for instance, to 10MM instead of 10,
> so the American will know it's not a 10inch end wrench, much less a
> 30inch on a large one. Lower case m's were not good enough either,
> while English sizes were not changed to show that they are in inches.
> I guess for some folks a 25x error is easy to make when measuring or
> selecting tools.
Yes I was dismayed as well when SnapOn started with the redundant _capital_
"MM" markings.
Every other brand of USA made wrench here is similarly marked ( although not
all in capital letters). My VAR, Weinmann and Hozan just display the
number.
I just expected more of SnapOn, an otherwise quality product.
--
Andrew Muzi
http://www.yellowjersey.org
Open every day since 1 April 1971
stu
>controlling the rear wheel? Most of us are right handed and would
>have better control if the right hand lever operated the front brake,
>in my opinion. But I digress.
move to Australia, we use right hand front brake. as to the reason l have
heard it has something to do with what side of the road you ride on, but as
far as l know no one has figured out for sure why some drive on the right
and some on the left so fell free to come up with your owe theory
Matt O'Toole
"MikeYankee" <mikey...@aol.comic.book> wrote in message
news:20030217102755...@mb-ms.aol.com...
> >lateral alignment between +-0.005 is fine
>
> Seems to be about twice what I can usually achieve
(depends somewhat on spoke
> count and rim type), and I haven't had any problems with
durability, brakes
> rubbing, etc. I'm satisfied to get the lateral trueness
within .25 mm by
> eyeball. How does one get closer than that, especially as
a slight waviness
> sets in as the wheel is brought up to final tension (e.g.,
~120 kgF drive-side
> tension on a road wheel with 14/15 DB spokes, measured by
Wheelsmith
> tensiometer)?
If the tension is even and the rim doesn't kiss the brake
pads intermittently as it goes around, then it's good enough
for me -- as it should be for anyone who isn't clinically
obsessive-compulsive. If you ask me to quantify this level
of straightness with a number, I can't tell you. I've never
bothered to measure it because it's irrelevent.
Dial, schmial.
Matt O.
Matt O'Toole
"stu" <s...@hotmail.com> wrote in message
news:3e5142d4$0$27765$afc3...@news.optusnet.com.au...
> >Does anyone know why bikes are made with the right hand
brake
> >controlling the rear wheel? Most of us are right handed
and would
> >have better control if the right hand lever operated the
front brake,
> >in my opinion. But I digress.
> move to Australia, we use right hand front brake. as to
the reason l have
> heard it has something to do with what side of the road
you ride on, but as
> far as l know no one has figured out for sure why some
drive on the right
> and some on the left so fell free to come up with your owe
theory
This horse has been beaten to a pulp here. I beleive it's
in the FAQ too. Please try a Google search rather than
start up another discussion about it! Please, oh please!
Matt O.
Frank Krygowski
>
> Lindsay Rowlands <lrow...@metz.une.edu.au> wrote in message news:<b2qcfs$858$1...@gruvel.une.edu.au>...
> > doubt there is any real benefit in a lower figure other than some kind of
>
> Regarding how true is true, I think it is a good question ‘cause I am
> interested to see the opinion of others. It seems as if ±0.005" is a
> good objective. A total swing of 0.01" easy to see without
> indicators, but the difference between 0.005 and 0.006" is impossible
> to know without dial indicators. I think I'll try to find some old
> feeler gauges or get some shim stock just to give me an idea how true
> my wheels are.
I just put a dial indicator on the wheels of a new bike we bought
(decent quality Terry bike, maybe 100 miles on it) and found 0.020"
TIR. Looking at this visually, I'd probably be perfectly satisfied with
this if I were building the wheel.
I didn't put the dial indicator on the two bikes I ride the most, but it
looks to me like they're at roughly 0.040" TIR. Like Lindsay, I'm
satisfied with that. It would need to be much worse before I'd feel the
need to straighten them. I should mention, though, that those bikes (my
touring bike and my commuting bike) both have cantilever brakes, so
dragging a super-sensitive double-pivot brake shoe isn't one of my
concerns.
Regarding Steve's statement: I'm not convinced "a total swing of 0.01"
[is] easy to see without indicators." A machinist's six inch rule goes
down to 0.01" resolution, and that's not real easy to read even with a
workpiece that's sitting still. Maybe you can see 0.01" on a rotating
wheel - but I bet you can't see it from five feet away!
--
Frank Krygowski frkr...@cc.ysu.edu
Robin Hubert
Doesn't this lead to awkward front brake cable routing?
Robin Hubert
Robin Hubert
"Matt O'Toole" <ma...@deltanet.com> wrote in message
news:KXc4a.17125$0L3.6...@news2.news.adelphia.net...
The truth is, just about every topic known to man regarding bicycling has
been beaten to death here. If old saws weren't re-sharpened, this newsgroup
would be dead.
Robin Hubert
Steven L. Sheffield
jobst....@stanfordalumni.org at jobst....@stanfordalumni.org wrote on
02/17/2003 12:18 AM:
Listen, fuckwad --
+-0.005 inches would be considered by most to be extremely accurate.
+-0.005 mm is even more accurate.
Can you visually tell the difference between 0.005 inches and 0.0001968
inches?
No? Neither can I.
That's why people use precision measuring tools, dipshit. As an engineer,
you should know this and know how important it is to specify units in
measurements.
After all, some NASA engineer made a mistake converting units a couple years
back which caused a launched satellite to get mispositioned ... it became a
multi-billion dollar pile of space-junk simply because somebody didn't
double-check the units of measurement.
Brown & Sharpe makes dial indicators accurate to 0.00005" ... that's
5/100,000 inches or 0.00127 mm, which is far more accurate than the +-0.005
"units" you suggest, but refuse to elaborate on.
In case you have trouble figuring it out, the dial indicator I'm referring
to is 100 times more accurate than 0.005", and 3.9370078 times more accurate
than 0.005 mm.
So which is it, Jobst?
Inches or millimetres?
--
Steven L. Sheffield
stevens at veloworks dot com
veloworks at worldnet dot ay tea tee dot net
bellum pax est libertas servitus est ignoratio vis est
ess ay ell tea ell ay kay ee sea aye tee why you ti ay aitch
aitch tee tea pea colon [for word] slash [four ward] slash double-you
double-yew double-ewe dot veloworks dot com [four word] slash
Saltytri
not to advertise the clinical compulsion that one poster observed. Rather, if
one wishes to become proficient at truing wheels but has no readily available
teacher/ mentor, the use of an objective measuring tool at the outset has real
instructional value. Chances are that with the experience gained from seeing
and feeling a wheel that is properly trued according to measurement, one can do
the job without relying on the numbers. Sure, I'd rather learn at the knee of a
master but, as far as I know, I'm the only guy on my block who has any interest
in messing around with bicycle wheels.
And thanks especially to Jobst, who has solved the minor mystery of why my
chainrings have "TA" written on them. This must stand for "Timid Anonymous" :)
Jon Isaacs
changed to show that they are in inches.
>I guess for some folks a 25x error is easy to make when measuring or
>selecting tools.
>
>Jobst Brandt
Guys (and Gals):
Those of you who doubt that Jobst has a sense of humor, well here it is, take
it or leave it. Personally I thought it was worth a chuckle or two.
Ten years ago I had a "mechanical engineering" student working in my (Materials
Science) Lab as a helper. One day I sent him out to change the spark plugs in
the old beater van and gave him the plugs and wrenches. He came back about an
hour later and hadn't been able to find the spark plugs. I guess it was lucky
I gave him the wrenches even though I have actually never seen a 13/16 mm
wrench. But all for not.
Oh well.....
jon isaacs
Frank Krygowski
>
> Ten years ago I had a "mechanical engineering" student working in my (Materials
> Science) Lab as a helper. One day I sent him out to change the spark plugs in
> the old beater van and gave him the plugs and wrenches. He came back about an
> hour later and hadn't been able to find the spark plugs.
Back when I was in engineering school, a friend and I were leaving
campus to meet some people at a guy's apartment. I was parked farther
away than he was. When I walked over and got into my car, it wouldn't
crank. Someone had disconnected the battery cables.
I thought it was that practical-joking friend. So I reconnected the
cables and drove to the apartment. Once there, I opened his hood and
removed the main ignition lead. (Yeah, this was back when you could
open a hood from the outside.)
Turned out it wasn't him. He was obviously innocent. I said "Well, I
guess you can have this, then," and gave his ignition lead back.
He said "What is it??"
"It's your ignition lead."
"What do I do with it?"
"You put it between your coil and your distributor."
"What's a coil? What's a distributor?"
He graduated less than a year later with a degree in Mechanical
Engineering.
Some engineers are much better at partial differential equations than
they are at elementary common knowledge.
--
Frank Krygowski frkr...@cc.ysu.edu
jt
"Steve Shapiro" <shap...@thermacell.net> wrote in message
news:4f586d95.03021...@posting.google.com...
>
> Does anyone know why bikes are made with the right hand brake
> controlling the rear wheel? Most of us are right handed and would
> have better control if the right hand lever operated the front brake,
> in my opinion. But I digress.
>
The right gear lever controls (usually) the rear mechanism. When stopping,
one finds it more convenient to shift down with the right and brake with the
left, as there is (again, usually) a greater gear variation possible with
the rear mech.
But there are, as Churchill said, all kinds <of right/left brake
arrangements>.
John Albergo
Saltytri wrote:
>I just put together a truing stand with dial indicators for radial and lateral
>truing. Also, a dish tool with a dial indicator. (No flames on this, please -
>I know that some will say that this level of precision is overkill but I like
>making things.) While Jobst's fine book suggests that dial indicators have
>some value, I haven't found any reference that tells me what level of truing
>and dish accuracy is considered acceptable.
>
Probably because it's a matter of personal preference. One could say as
long as you can spin the wheel without the brakes rubbing, that's close
enough. Hell, even a little brake rub isn't the end of the world. So,
to quote from Cool Hand Luke, "It's all up to You".
Most people's sense of "quality" is going to lead to better trueness
than the above anyway. Given that, you should probably focus more on
stress relief, even tension and good spoke line. A wheel with 1mm
deviation but otherwise sound will stay that way for a long time. A
wheel can be built to near perfect trueness but ignoring the other
factors can self-destruct on the first ride.
This is why a dial indicator is not of much use, in my opinion. We're
not machining a bearing surface -- again, we're only trying to "fit"
inside the brake shoes, and maybe a bit better than that, to have smooth
braking. Radially, we want to prevent any feeling of "hop" and the same
level of accuracy works there too. A visual (and auditory) observation
with a fixed reference tells you as much as you need to know to get the
wheel WAY more than true enough. All else is vanity.
> I don't have enough experience to
>know by look/feel/calipers when a wheel is considered good enough so I can't
>translate build quality by those more subjective standards into objective
>measurement criteria. What are reasonable targets in thousanths?
>
.001M
E & V Willson
lateral) using magnetic bases to hold dial indicators on the chain stays. Then I
bought a truing stand. The stand instructions suggest that all that is necessary is
+- 1/2 mm (0.020") for both hop and wobble. Since getting the stand the +- 1/2 mm
has been my standard, with no noticabable difference in performance from the
earlier 0.004". HTH
Ernie
Saltytri wrote:
> I just put together a truing stand with dial indicators for radial and lateral
> truing. Also, a dish tool with a dial indicator. (No flames on this, please -
> I know that some will say that this level of precision is overkill but I like
> making things.) While Jobst's fine book suggests that dial indicators have
> some value, I haven't found any reference that tells me what level of truing
> and dish accuracy is considered acceptable. I don't have enough experience to
CBike
wouldn't go back. Once on to a technique I find it speeds the time considerably
in truing. I shoot for 0.010" which is relatively quick to get to.
Charlie
Benjamin Weiner
> Jon Isaacs wrote:
>> Ten years ago I had a "mechanical engineering" student working in my
>> (Materials Science) Lab as a helper. One day I sent him out to change the
>> spark plugs in the old beater van and gave him the plugs and wrenches. He
>> came back about an hour later and hadn't been able to find the spark plugs.
> ... He said "What is it??"
> "It's your ignition lead."
> "What do I do with it?"
> "You put it between your coil and your distributor."
> "What's a coil? What's a distributor?"
> Some engineers are much better at partial differential equations than
> they are at elementary common knowledge.
Hey you hosers,
This is a BICYCLE newsgroup. Cars are not necessarily elementary common
knowledge. There is a tradition of young people (often men) learning by
dinking around with cars in their adolescence, but not everybody does that.
I am mechanically inclined, but I grew up in a city and didn't learn to drive
until the age of 21. (We had a car, I just didn't need to drive it for the
independence.) I taught myself to fix a broken bicycle axle before I learned
to change a spark plug. Cars are also big, expensive and intimidating, and
many people simply do not want to mess around under the hood.
Modern cars are also less amenable to shade-tree repair (and more reliable so
you don't need to bother). My current car doesn't even have a distributor.
Geez-, uh, veteran engineers might want to keep this in mind next time they
are inclined to lament the mechanical inability of the younger generation.
Despite occasional noises about the passing of the Good Old Days, bicycles
have not evolved nearly as far as cars in the direction of home
inserviceability; most repairs can still be effected with simple hand tools.
(I guess cartridge BBs, STI levers, and some boutique wheels to be the
exceptions.)
jobst....@stanfordalumni.org
> This is a BICYCLE newsgroup. Cars are not necessarily elementary
> common knowledge. There is a tradition of young people (often men)
> learning by dinking around with cars in their adolescence, but not
> everybody does that.
It's not cars but machines that interest mechanically attuned people.
Some people do not recognize that we are surrounded by machines and
tools, be they child's toys or kitchen mixers. They all deserve
scrutiny by the future engineer or household mechanic.
> I am mechanically inclined, but I grew up in a city and didn't learn
> to drive until the age of 21. (We had a car, I just didn't need to
> drive it for the independence.) I taught myself to fix a broken
> bicycle axle before I learned to change a spark plug. Cars are also
> big, expensive and intimidating, and many people simply do not want
> to mess around under the hood.
I don't share your perception of a mechanically inclined person. I
for one, with friends, repaired cars long before I was old enough for
a learner's license. It was fixing household equipment and vehicles
that I got my engineering education that was formalized later with the
underlying science in school.
> Modern cars are also less amenable to shade-tree repair (and more
> reliable so you don't need to bother). My current car doesn't even
> have a distributor. Geez-, uh, veteran engineers might want to keep
> this in mind next time they are inclined to lament the mechanical
> inability of the younger generation.
That is true, but for that there are many more machines that can be
fixed and they need not be cars. However, a former service manager at
a major auto mechanic shop told me recently that when his car stops,
all he can do is call the towing service, trivial parts no longer
failing in new cars. That doesn't mean that we don't know how the car
works. I have never worked on a diesel engine, caterpillar or railroad,
but don't find their workings foreign. The same goes for steam engines.
> Despite occasional noises about the passing of the Good Old Days,
> bicycles have not evolved nearly as far as cars in the direction of
> home inserviceability; most repairs can still be effected with
> simple hand tools. (I guess cartridge BBs, STI levers, and some
> boutique wheels to be the exceptions.)
That is primarily the case because the motor, the human being on the
bicycle is the main failure component. I hope not to see more
electronic or more complex hardware on bicycles because they don't
improve the bicycle. The shape of ball bearings and parts are not
going to change visibly, regardless of how hard manufacturers try to
make them more "space aged".
Kraig Willett
news:b2qcfs$858$1...@gruvel.une.edu.au...
> single pivoted bike climbs just as easily as my dual pivoted one. Sounds
> like bicycle folklore.
What don't you buy, that rims rub brakes, or, that racers open up their rear
brakes?
I can definitively comment on the rub issue, since I made the physical
measurements with a dial indicator while riding.
It depends on the wheel, of course, but many of today's low
spoke/lightweight wheels rub pads.
The measurements I made were published in this online magazine article:
--
==================
Kraig Willett
www.biketechreview.com
==================
Kraig Willett
time flies!), the spec we enforced was in the 0.012" TIR range.
Jon Isaacs
>> I am mechanically inclined, but I grew up in a city and didn't learn
>> to drive until the age of 21. (We had a car, I just didn't need to
>> drive it for the independence.) I taught myself to fix a broken
>> bicycle axle before I learned to change a spark plug.
I just hope that after an hour of looking, you didn't give up because you
couldn't find the spark plugs.
Jon Isaacs
David Damerell
>Frank Krygowski <frkr...@cc.ysu.edu> wrote:
>>... He said "What is it??"
>>"It's your ignition lead."
>>"What do I do with it?"
>>"You put it between your coil and your distributor."
>>"What's a coil? What's a distributor?"
>>Some engineers are much better at partial differential equations than
>>they are at elementary common knowledge.
>knowledge.
Are they to me? No; I don't drive and I don't generally live with
motorists.
[That said, even I know what the parts in Frank Krygowski's anecdote are,
although I couldn't recognise them.]
But the anecdote is not about any average person; it's about an engineer
who owned a motor car.
Steve Shapiro
Thank you, I hadn't thought of the shifting while braking issue. I'd
guess this could be important to racers or anyone seeking speed. My
road bike has down tube shifters, and you are correct, the only way to
shift and brake simultaneously is to use two hands. I'm not real good
at it. But my hybrid has rapid-fire shifters and ATB brake levers.
It's no problem for me to brake and shift with one hand as long as
braking is light to moderate. My personal preference remains to use
the front caliper, right hand combination and downshift before or
after deceleration.
Steve Shapiro
Steve Shapiro
> "Lindsay Rowlands" <lrow...@metz.une.edu.au> wrote in message
> news:b2qcfs$858$1...@gruvel.une.edu.au...
> > I don't buy Jobst's version of brake pads rubbing on rims. Curiously, my
> > single pivoted bike climbs just as easily as my dual pivoted one. Sounds
> > like bicycle folklore.
>
> What don't you buy, that rims rub brakes, or, that racers open up their rear
> brakes?
>
> I can definitively comment on the rub issue, since I made the physical
> measurements with a dial indicator while riding.
>
> It depends on the wheel, of course, but many of today's low
> spoke/lightweight wheels rub pads.
>
> The measurements I made were published in this online magazine article:
>
> http://tinyurl.com/6424
Thanks for pointing me to your article. I enjoyed it. Suspicions
confirmed. One quick question: Did you do any of the deflection tests
with a 36 spoke, basic hub, basic rim wheel?
Steve Shapiro
Steve Shapiro
> Back when I used to work in the wheel industry (3 years ago now - whew, how
> time flies!), the spec we enforced was in the 0.012" TIR range.
I know what you mean about time. I did want to take the time to say
thank you for the information. This may sound stupid, but I assume
you speak of hand built vs. machine built wheels. Right?
Steve Shapiro
Steve Shapiro
You win the bet from five feet, but I maintain it is easy to see
0.010" when viewed from a comfortable wheel truing distance (assume no
tire, assume white background like on a Park stand. As I write, my
electronic caliper is set to 0.0100" and I'm looking at the gap
between the jaws. It is easy to see. On the other hand, I have no
arguement with how important it is to build wheels to any particular
tolerance. Whatever serves and pleases you.
Steve Shapiro
Kraig Willett
All the experience I have is with hand built wheels.
Kraig Willett
I don't own any 36 hole rear wheels; however, I think I did measure some of
my other wheels at the time. Let me dig through the data and put something
together.
Scic
Somebody wrote:
>> A machinist's six inch rule goes down to 0.01" resolution, and that's not
real easy to read even with a workpiece that's sitting still. Maybe you can
see 0.01" on a rotating wheel - but I bet you can't see it from five feet away!
Steve wrote:
>You win the bet from five feet, but I maintain it is easy to see 0.010" when
viewed from a comfortable wheel truing distance
A good set of young eyes can easily see a gap of .005". Better eyes, down to
.003".
Backlighting is usually needed for anything less.
Sig
Chicago
Benjamin Weiner
> >> I taught myself to fix a broken
> >> bicycle axle before I learned to change a spark plug.
> I just hope that after an hour of looking, you didn't give up because you
> couldn't find the spark plugs.
Well, after 10-15 minutes I would have realized I was over my head and
asked somebody. That's where your student went wrong. He was probably
intimidated and trying to make a good impression (oops). Not asking for
help is related to what Jobst calls Male Answer Syndrome ...
My first serious solo car repair was nothing much (a cracked vacuum hose)
but it turned the car from completely dead to running normally, confirming
that it was not inscrutable but another thing I could fix, just bigger.
Because I remember the original mystification, I have some sympathy for
your student. Similarly, one must be gentle and enccourage cyclists who
have understood or attempted to fix their own vehicles. Not everyone
has an upbringing that encourages taking stuff apart - all too many kids
get their hands slapped.
Tom Nakashima
in which I thought
the unit of measure was inches. In inches it was actually .00197", simple
mistake, large error.
-tom
<jobst....@stanfordalumni.org> wrote in message
news:e104a.66708$Ik.28...@typhoon.sonic.net...
> Shane Stanley writes:
>
> >> Depending on what sort of brakes and pad clearance you use, lateral
> >> alignment between +-0.005 is fine.
>
> > What units are you using there?
>
> Oh how clever. What else? Did you perhaps think millimeters,
> nanometers, or Angstroms. This reminds me of Snap-on Tools changing
> their metric wrench markings to, for instance, to 10MM instead of 10,
> so the American will know it's not a 10inch end wrench, much less a
> 30inch on a large one. Lower case m's were not good enough either,
> while English sizes were not changed to show that they are in inches.
> I guess for some folks a 25x error is easy to make when measuring or
> selecting tools.
>
jobst....@stanfordalumni.org
> I once had a Japanese engineer give me the measurement of .005
> centimeters, in which I thought the unit of measure was inches. In
> inches it was actually .00197", simple mistake, large error.
That sounds odd for an engineer, and one who uses the metric system.
Engineering is done in millimeters, be that a wristwatch or a railway
locomotive. Centimeters are used in architecture and are not used to
1/1000 resolution. I'm curious what the measurement was and how it
came to be given in centimeters.
Frank Krygowski
> > "It's your ignition lead."
> > "What do I do with it?"
> > "You put it between your coil and your distributor."
> > "What's a coil? What's a distributor?"
> > Some engineers are much better at partial differential equations than
> > they are at elementary common knowledge.
>
> Hey you hosers,
>
> This is a BICYCLE newsgroup. Cars are not necessarily elementary common
> knowledge. There is a tradition of young people (often men) learning by
> dinking around with cars in their adolescence, but not everybody does that.
>
> many people simply do not want to mess around under the hood.
FWIW, we were talking about engineering students. Personally, I feel
that a person who's going to be a mechanical engineer _should_ know what
goes on inside that big, intimidating engine compartment. I think that,
in a prospective engineer, failure to learn that hints at a mistaken
career choice.
Come to think of it, I guess I think _everyone_ should know at least a
little about what goes on inside their car. Hell, I know a woman who is
a teacher and poet, and who has changed her own oil, replaced her spark
plugs, replaced her own pads and rotors, etc. The willingness to tackle
jobs like that speaks well of her, I'd say.
For poets, housewives, accountants etc. this knowledge at least allows
one to take minimal care of their vehicle, to avoid destroying it before
its time. It also helps to avoid being ripped off by unscrupulous
repair shops.
But for anyone with minimal technical curiosity - how can you _not_ be
curious about your car? You probably rely on it very heavily in daily
life. Do you really want to rely on some incomprehensible, sealed black
box? Do you somehow get all nervous and trembly when you lift the
hood? How strange!
Go to the library. Get out a book on the workings of the car, something
intended for novice consumers. Read the book, look at the pictures, and
find the parts they discuss inside your own engine compartment. It
can't do you any harm, and it might do you a lot of good.
--
Frank Krygowski frkr...@cc.ysu.edu
J. Bruce Fields
Frank Krygowski <frkr...@cc.ysu.edu> wrote:
>Benjamin Weiner wrote:
>> Hey you hosers,
>>
>> This is a BICYCLE newsgroup. Cars are not necessarily elementary common
>> knowledge. There is a tradition of young people (often men) learning by
>> dinking around with cars in their adolescence, but not everybody does that.
>
>little about what goes on inside their car.
This presupposes that they have one!
--Bruce F.
David Damerell
>Come to think of it, I guess I think _everyone_ should know at least a
>little about what goes on inside their car.
_Everyone_ hasn't got one of the damn things. I haven't.
--
David Damerell <dame...@chiark.greenend.org.uk> Kill the tomato!
Frank Krygowski
>
> Frank Krygowski <frkr...@cc.ysu.edu> wrote:
> >Come to think of it, I guess I think _everyone_ should know at least a
> >little about what goes on inside their car.
>
> _Everyone_ hasn't got one of the damn things. I haven't.
OK, you're exempt.
--
Frank Krygowski frkr...@cc.ysu.edu
jobst....@stanfordalumni.org
>> Come to think of it, I guess I think _everyone_ should know at
>> least a little about what goes on inside their car.
> _Everyone_ hasn't got one of the damn things. I haven't.
You don't have to own one to understand their workings, just as I
don't have a steam or diesel railway locomotive but understand how
they work in fairly fine detail. The mechanical and thermodynamic
complexities of internal combustion engines is essential to many
machines and should be understood by those affected by their
performance. This is especially true for mechanical engineers to whom
this is like understanding mathematics. It's full of dynamic stress,
tribology, combustion, heat transfer (solid, liquid and gas),
electronics, vibration control, and a slew of other considerations.
Your comment of "one of the damn things" makes me sure I wouldn't want
you on my engineering team.
David Damerell
>David Damerell writes:
>>>Come to think of it, I guess I think _everyone_ should know at
>>>least a little about what goes on inside their car.
>>_Everyone_ hasn't got one of the damn things. I haven't.
>You don't have to own one to understand their workings,
Where did I say that I don't understand their workings? I may not know
what many of the parts look like beyond what is obvious from their
function, but that doesn't mean I don't know roughly what they are.
What I objected to was the idea that "everyone" should know about "their"
car.
>Your comment of "one of the damn things" makes me sure I wouldn't want
>you on my engineering team.
I don't think the belief that motor cars are socially destructive
automatically renders one unqualified to be an engineer.
Benjamin Weiner
> It's not cars but machines that interest mechanically attuned people.
> Some people do not recognize that we are surrounded by machines and
> tools, be they child's toys or kitchen mixers. They all deserve
> scrutiny by the future engineer or household mechanic.
> I don't share your perception of a mechanically inclined person. I
> for one, with friends, repaired cars long before I was old enough for
> a learner's license. It was fixing household equipment and vehicles
> that I got my engineering education that was formalized later with the
> underlying science in school.
I agree, except that I understand the reasons why a young person might
not
work on cars (bigger, expensive, Dad gets madder if you take it apart
without
knowing how to put it back together).
Unfortunately, modern gadgets of many kinds are less repairable than
their
predecessors, due to miniaturization, electronics, and cheap labor
which
makes it cheaper to buy a new gizmo (clock, radio, phone, TV, camera)
rather than repair one. I enjoy the benefits of these advances but
with a twinge of
regret. As you say there will always be something that a mechanically
minded person can mess around with. I'd like to think that bicycles
will
remain so - their dimensions cannot be usefully miniaturized and there
is
limited application for proprietary electronics (I hope!)
Jobst, have you read "The English Patient"? I think you would enjoy
the chapter describing the training of the Indian sapper and
bomb-defuser,
first in India, repairing and improvising fixes to keep things
running,
as one does in countries where resources are scarce, and then in
England
in the bomb squad. His reaction upon coming to England is "There were
enough spare parts in England to keep India running for a lifetime."
I often think of this as I see the increasingly disposable nature of
the objects we in rich countries are fortunate enough to posess.
Sorry for the dealy in responding to your post,
Ben
Sergio SERVADIO
> His reaction upon coming to England is "There were
> enough spare parts in England to keep India running for a lifetime."
> I often think of this as I see the increasingly disposable nature of
> the objects we in rich countries are fortunate enough to posess.
Starting today I'll feel like an Indian when I walk into my favorite
bike shop. There, I am used to pick for free used spares to assembly
more and more excellent, out of fashion, racing bicycles.
I dare not think of the day I run short of garage space.
Sooner or later it has got to happen.
Sergio
Pisa