Who invented dual-pivot brakes?
Jeff
well enough. Rode through the 80s and 90s on sidepulls. They worked a bit
better.
Today I installed my first dual-pivot side-pull brakes. The easiest
adjusting brakes I know, by far.
Curious - who invented this marvel?
Sheldon Brown
In one sense, they go back to the Dawn of Time, because cantilevers and
centerpulls are technically "dual pivot."
However, if youre speaing of modern dual pivot sidepulls, the earliest
ones I know of were made by Altenberger in the late '60s.
They were generally considered slightly inferior to the popular
centerpull calipers of the day from Mafac, Weinmann, Universal and GB.
The superiority of modern brakes has much more to do with improved
levers, cables and shoes than it does with caliper design.
Sheldon "Used To Ride With An Altenberger On The Back" Brown
+---------------------------------------+
| Whatever became of eternal truth? |
+---------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
Jeff
> The superiority of modern brakes has much more to do with improved
> levers, cables and shoes than it does with caliper design.
My [limited] experience is I could never fine-tune single-pivot side-pull
brakes.
Seems like the dual-pivots are much, much easier.
Chris Zacho The Wheelman
May you have the wind at your back.
And a really low gear for the hills!
Chris
Chris'Z Corner
"The Website for the Common Bicyclist":
http://www.geocities.com/czcorner
jobst....@stanfordalumni.org
>> An intermittent cyclist, I rode throughout 70s on centerpulls. They
>> worked well enough. Rode through the 80s and 90s on sidepulls. They
>> worked a bit better.
>> Today I installed my first dual-pivot side-pull brakes. The easiest
>> adjusting brakes I know, by far.
>> Curious - who invented this marvel?
> In one sense, they go back to the Dawn of Time, because cantilevers
> and centerpulls are technically "dual pivot."
I think you should be more exacting in the definition. THE dual pivot,
as we know it today, was introduced for its forced centering that can
only be done with two pivot points. It is this self centering that
makes possible the higher mechanical advantage... the feature that
most people like about them. Centerpull are self contained
cantilevers and both suffer from large cosine error, the pivot points
being on a nearly 45 degree axis from pad contact... dogs!
http://draco.acs.uci.edu/rbfaq/FAQ/8f.15.html
> However, if you're speaking of modern dual pivot sidepulls, the
> earliest ones I know of were made by Altenburger in the late '60s.
Yes, but they did not take advantage of the lower pad clearance
possible with centered brakes. They didn't see the need and were to
timid to diverge from the standard 4:1 mechanical advantage of the day.
> They were generally considered slightly inferior to the popular
> centerpull calipers of the day from Mafac, Weinmann, Universal and
> GB.
That was a bunch of marketing. I chucked the centerpulls immediately
and switched to Universal side pulls before Campagnolo brakes were
generally available. Centerpull brakes were duds right from the start
but were touted to have greater stopping power because they had twice
the force... a complete lie. They had 4:1 like all brakes of the day.
> The superiority of modern brakes has much more to do with improved
> levers, cables and shoes than it does with caliper design.
It has only one feature and that is a higher mechanical advantage.
The short arm on the offset pivot has significant cosine error
(foreshortening caused by angular motion. A conventional side pull
brake operating at less than 5 degrees has less than 4% vertical
motion of the pad from new to worn to the metal. No other mechanical
lever brake can be operated for the life of the pad without
adjustment. The pad position on my old Campagnolo brakes never need
adjustment. Only cable slack from pad wear need be taken up and it
can do that as well.
Jobst Brandt
jobst....@stanfordalumni.org
Palo Alto CA
Dave Mayer
vintage, and pretty good shape. They're mine for free if I want to drop
them on a bike. Is there any point for me to do this?
"Chris Zacho "The Wheelman"" <Chrisz...@webtv.net> wrote in message
news:10808-3E...@storefull-2356.public.lawson.webtv.net...
Qui si parla Campagnolo
errrrr, thank you for playing....
like most things 'bike', shimano is wonderful at improving the design, but
original designs are not something 'shimano'....
Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"
Neacalban1
>> well enough. Rode through the 80s and 90s on sidepulls. They worked a bit
>> better.
>>
not very demanding, were you? todays dual-pivot brakes are far and away
easier to adjust,maintain, and offer much greater modulation and stopping
power than what was available back then(yeah, I know, thats what you inferred.
:-)
I was just reminiscing- Sears Free Spirit- with steel side-pulls with "safety
levers" - amazing how many people didnt get killed on those. Dura-Ace
brakes(mine was circa 1976)- my set was hard to adjust and had an incredible
squeal. no matter how far I toed them, tightened them, whatever. a neighbor who
worked for NASA(harbinger of Challenger....?) said it was pressure and not
friction that stpped the wheels, so he sprayed silicone on the brake pads for
me..... I went down the hill with the levers locked to the bars- no squeal,no
stop. never bought another Shimano part.
all those steel sidepulls- took forever to smack the springs just right.
Waal
"Qui si parla Campagnolo" <vecc...@aol.com> skrev i en meddelelse
news:20030601090454...@mb-m25.aol.com...
> chris-<< Shimano, I believe.
>
>
> errrrr, thank you for playing....
>
> like most things 'bike', shimano is wonderful at improving the design, but
> original designs are not something 'shimano'....
maybe something like
:http://www.classicrendezvous.com/British/conloy_3_brks.html
Michael
Sheldon Brown
> Centerpull are self contained
> cantilevers and both suffer from large cosine error, the pivot points
> being on a nearly 45 degree axis from pad contact... dogs!
>
> http://draco.acs.uci.edu/rbfaq/FAQ/8f.15.html
The popularity of centerpull calipers was in a time when most rims had
angled braking surfaces, as opposed to the parallel braking surfaces
that are now the norm.
For such rims, the cosine "error" of centerpull calipers (or "U brakes")
is actually a feature!
I had reminisced:
>>However, if you're speaking of modern dual pivot sidepulls, the
>>earliest ones I know of were made by Altenburger in the late '60s.
> Yes, but they did not take advantage of the lower pad clearance
> possible with centered brakes. They didn't see the need and were to
> timid to diverge from the standard 4:1 mechanical advantage of the day.
>>They were generally considered slightly inferior to the popular
>>centerpull calipers of the day from Mafac, Weinmann, Universal and
>>GB.
> That was a bunch of marketing. I chucked the centerpulls immediately
> and switched to Universal side pulls before Campagnolo brakes were
> generally available. Centerpull brakes were duds right from the start
> but were touted to have greater stopping power because they had twice
> the force... a complete lie. They had 4:1 like all brakes of the day.
The Universals were very nice calipers indeed. However, I believe that
comparing '60s and '70s centerpulls with garden variety long-reach
sidepulls, as fitted on "sport-touring" tenspeeds of the era, the
centerpulls generally had a higher mechanical advantage, at least when
properly set up.
>>The superiority of modern brakes has much more to do with improved
>>levers, cables and shoes than it does with caliper design.
> It has only one feature and that is a higher mechanical advantage.
> The short arm on the offset pivot has significant cosine error
> (foreshortening caused by angular motion. A conventional side pull
> brake operating at less than 5 degrees has less than 4% vertical
> motion of the pad from new to worn to the metal. No other mechanical
> lever brake can be operated for the life of the pad without
> adjustment.
That generalization has been invalidated by the move to thinner pads!
It also doesn't apply to centerpulls used with angled rims, nor to
various brake types used with rims with a tall braking surface, such as
the (yuck!) Weinmann concave.
> The pad position on my old Campagnolo brakes never need
> adjustment. Only cable slack from pad wear need be taken up and it
> can do that as well.
This feature is certainly of some value, but it isn't overwhelming. Not
all cyclists have as strong hands as you do, and some of us with weak
hands find old Campagnolo sidepulls highly unsatisfactory.
Sheldon "Current Campag Brakes Are Fine" Brown
+----------------------------------------+
| The race is not always to the swift, |
| nor the battle to the strong |
| -but that's the way to bet. |
| --Damon Runyon |
+----------------------------------------+
Mike S.
"Qui si parla Campagnolo" <vecc...@aol.com> wrote in message
news:20030601090454...@mb-m25.aol.com...
> chris-<< Shimano, I believe.
>
>
> errrrr, thank you for playing....
>
> like most things 'bike', shimano is wonderful at improving the design, but
> original designs are not something 'shimano'....
>
>
> Peter Chisholm
Just like the "Bullseye" cranks that Shimano is bringing out this year for
D/A and XTR...
Mike
Jeff
I have nightmares about that. Glad you survived to tell the tale.
"Neacalban1" <neaca...@aol.com> wrote
Donald Gillies
>Jeff wrote:
>> Today I installed my first dual-pivot side-pull brakes. The easiest
>> adjusting brakes I know, by far. Curious - who invented this marvel?
>
>The superiority of modern brakes has much more to do with improved
>levers, cables and shoes than it does with caliper design.
I love the action of the old centerpulls. Since the centerpulls (and
cantilevers) are basically lengthening a rhombus, they have (i think)
twice the mechanical advantage, but twice the lever travel. that's
why the old weinmann levers stuck out so far in front of the
handlebars, and why "suicide levers" (e.g. dia compe extensions)
didn't work.
In my opinion, campy sidepulls were not an improvement over
centerpulls. They were just lighter, thats all. Weinmann Centerpulls
(and most cantilevers) can crush a tandem wheel if you reaally need to
stop quickly. sidepulls cannot do that, never in the past, and never
in the future ...
- Don Gillies
San Diego, CA
David L. Johnson
> Dura-Ace
> brakes(mine was circa 1976)- my set was hard to adjust and had an incredible
> squeal. no matter how far I toed them, tightened them, whatever. a neighbor who
> worked for NASA(harbinger of Challenger....?) said it was pressure and not
> friction that stpped the wheels, so he sprayed silicone on the brake pads for
> me..... I went down the hill with the levers locked to the bars- no squeal,no
> stop. never bought another Shimano part.
I think you're blaming the wrong people for that. How an engineer could
say that is beyond comprehension.
--
David L. Johnson
__o | "What am I on? I'm on my bike, six hours a day, busting my ass.
_`\(,_ | What are you on?" --Lance Armstrong
(_)/ (_) |
Tim McNamara
neaca...@aol.com (Neacalban1) wrote:
> todays dual-pivot brakes are far and away easier to adjust,
> maintain, and offer much greater modulation and stopping power
These things are mutually exclusive in a simple lever like a bicycle
rim brake. You might personally find dual pivots to be a better
compromise than, say, single pivot brakes.
Alex Rodriguez
>Just like the "Bullseye" cranks that Shimano is bringing out this year for
>D/A and XTR...
The ones with the Magic Motorcycle/CODA outside of the BB shell bearings?
Hollow like the MM/CODA cranks? The only part they didn't copy was a
lobed tapered press fit interface between the cranks and BB.
----------------
Alex
jobst....@stanfordalumni.org
>> It has only one feature and that is a higher mechanical advantage.
>> The short arm on the offset pivot has significant cosine error
>> (foreshortening caused by angular motion. A conventional side pull
>> brake operating at less than 5 degrees has less than 4% vertical
>> motion of the pad from new to worn to the metal. No other
>> mechanical lever brake can be operated for the life of the pad
>> without adjustment.
> That generalization has been invalidated by the move to thinner
> pads! It also doesn't apply to centerpulls used with angled rims,
> nor to various brake types used with rims with a tall braking
> surface, such as the (yuck!) Weinmann concave.
There is no rim surface that will negate cosine error. Pad thickness
only comes into play to make pads wear out so fast that they need to
be replaced often, thereby keeping the angular change close to zero.
That is a stupid solution and it does nothing for cantilever and
V-brakes that have large cosine error.
>> The pad position on my old Campagnolo brakes never need
>> adjustment. Only cable slack from pad wear need be taken up and it
>> can do that as well.
> This feature is certainly of some value, but it isn't overwhelming. Not
> all cyclists have as strong hands as you do, and some of us with weak
> hands find old Campagnolo sidepulls highly unsatisfactory.
It is important if you use the brakes on long descents, in the Alps in
the rain, for instance. I can imagine this happening n the great tour
races, TdF, GdI, TdS and others. Just because most Americans don't
ride such courses, straying that far from their bicycle mechanic,
doesn't justify such an unnecessary built in error.
By the way, current dual-pivot brakes can lock up a front wheel if it
gets knocked a couple of centimeters out of true, such as a 24-spoke
wheel in which a spoke breaks on a descent. The Dual pivot brake
cannot follow an untrue wheel as single pivot brakes have done on
purpose for many years. I am not amused and fortunately have hands
strong enough to raise the rear wheel on descents if I need to brake
that hard.
jobst....@stanfordalumni.org
> I love the action of the old centerpulls. Since the centerpulls
> (and cantilevers) are basically lengthening a rhombus, they have (i
> think) twice the mechanical advantage, but twice the lever travel.
> that's why the old Weinmann levers stuck out so far in front of the
> handlebars, and why "suicide levers" (e.g. Dia Compe extensions)
> didn't work.
Not true! These brakes all had a 4:1 ratio that was entirely in the
hand lever... the distance from the pivot to the cable and the
distance from the hand lever crook from that same pivot. The calipers
were all 1:1. Of course that is easy to measure. Measure pad
clearance (this can be done by pushing one pad to the rim and
measuring the resulting clearance on the other pad. Then measure how
much hand lever cable moves to bring the pads into contact with the
rim.
> In my opinion, Campy sidepulls were not an improvement over
> centerpulls. They were just lighter, thats all. Weinmann
> Centerpulls (and most cantilevers) can crush a tandem wheel if you
> really need to stop quickly. sidepulls cannot do that, never in the
> past, and never in the future...
Oh Bull Shit! I can see you will lose a bunch of money if you take
bets on that. Besides, the migration of pad contact into the tire
(aka cosine error) is a major hazard for people unclear on the concept
because it causes blowouts. Cantilevers, in contrast, "pop under" the
rim with wear and do not return, leaving the bicycle with no brake.
If you find that no improvement then it is a matter of definition. I
disagree.
Tom Ace
> > The pad position on my old Campagnolo brakes never need
> > adjustment. Only cable slack from pad wear need be taken up and it
> > can do that as well.
>
> This feature is certainly of some value, but it isn't overwhelming. Not
> all cyclists have as strong hands as you do, and some of us with weak
> hands find old Campagnolo sidepulls highly unsatisfactory.
>
> Sheldon "Current Campag Brakes Are Fine" Brown
Correct me if I'm wrong, but didn't the (original) Campagnolo
calipers have roughly the same mechanical advantage as other
sidepulls of the time (e.g. Universal Super 68)? I'd thought
that the greater effort required was due to the design of
Record levers, not the calipers.
Tom Ace
David E. Belcher
> However, if youre speaing of modern dual pivot sidepulls, the earliest
> ones I know of were made by Altenberger in the late '60s.
>
> They were generally considered slightly inferior to the popular
> centerpull calipers of the day from Mafac, Weinmann, Universal and GB.
Beat me to it! Think they were a joint venture with GB, being marketed
over here as the "GB Synchron". The Classic Rendezvous website has a
bit of info, plus an advert of the time, under its "British
Components" section.
David E. Belcher
Dept. of Chemistry,
University of York
Qui si parla Campagnolo
year for
D/A and XTR...
And altho I sometimes 'like' to slam shimano for some of what they do, they are
responsible for many improvemnets that have brought people back to bikes and
kept them there, like lever mounted click shifting. Tremendous improvers, not
inventors tho.
Anthony Leverock
<capt...@sheldonbrown.com> spat out his venom thus:
>
>> It has only one feature and that is a higher mechanical advantage.
>> The short arm on the offset pivot has significant cosine error
>> (foreshortening caused by angular motion. A conventional side pull
>> brake operating at less than 5 degrees has less than 4% vertical
>> motion of the pad from new to worn to the metal. No other mechanical
>> lever brake can be operated for the life of the pad without
>> adjustment.
>
>That generalization has been invalidated by the move to thinner pads!
>It also doesn't apply to centerpulls used with angled rims, nor to
>various brake types used with rims with a tall braking surface, such as
>the (yuck!) Weinmann concave.
Ouch! I believe the Concave was an outstanding rim - strong and
durable -- they made for an excellent wheel. Why do you dis them?
- --
Anthony Leverock
Sheldon Brown
>>...the (yuck!) Weinmann concave [rim].
Anthony Leverock wrote:
> Ouch! I believe the Concave was an outstanding rim - strong and
> durable -- they made for an excellent wheel. Why do you dis them?
Ugly, heavy, anti-aerodynamic, and, most of all, incompatible with my
favorite spoke wrench! Also, they often had rather poorly finished joints.
Sheldon "Liked The 210" Brown
+------------------------------------------------------+
| It were not best that we should all think alike; |
| it is difference of opinion that makes horse-races. |
| -- Mark Twain |
+------------------------------------------------------+
Anthony Leverock
<capt...@sheldonbrown.com> explained:
>
>>>...the (yuck!) Weinmann concave [rim].
>
>Anthony Leverock wrote:
>
>> Ouch! I believe the Concave was an outstanding rim - strong and
>> durable -- they made for an excellent wheel. Why do you dis them?
>
>Ugly, heavy, anti-aerodynamic, and, most of all, incompatible with my
>favorite spoke wrench! Also, they often had rather poorly finished joints.
Heheh, pishposh regarding the ugly and non-aerodynamic comments, and I
haven't seen a pooly finished joint on one, but I am going on memory
from about 20 years ago - the rims I have (still in service!) look
very fine. However, your point is well taken on the spoke wrench
issue. I cannot use a VAR spoke wrench on a Concave when it is
matched with normal length nipples.(the wings rub on the rim). Of
course, there are plenty of other wrenches out there to fall back to
when working on one.
Heavy - hmm, yes a bit, but as I said very durable and strong.
- --
Anthony (Into The Concave) Leverock
Matt O'Toole
<jobst....@stanfordalumni.org> wrote in message
news:S9BCa.18761$JX2.1...@typhoon.sonic.net...
My hands are not particularly strong and I have no problem
with good single pivots. However, many of them are (or
were) not good. The problems I've most encountered are bad
pads, flexy calipers, flexy levers, sloppy lever pivots,
sloppy cable installations with badly seated housings, etc.
Maybe older cable housings compressed a bit too, I don't
know.
A couple of years ago I had an old bike with Superbe Pro
brakes. Whe I rode it home, I almost shot through a couple
of stop signs. But once I rebuilt the brakes with new pads
and cables it was fine. I've ridden a friend's bike a lot
in the Santa Monica Mts., descending those steep hills above
Malibu. This bike has mid-90s Campy Mirage single pivots.
No problem -- the brakes are excellent. Descending these
same hills years ago on an early 90s MTB with stock Shimano
canti brakes, I had to stop periodically to rest my aching
forearms.
Dual pivots definately have more leverage, but I don't think
it's a big deal. It's kind of like machined sidewalls -- a
"solution" a bike salesman can point to, that resonates
instantly with the buyer. No more sloppy rim joints that
cause the brakes to hang up. Of course the real problem was
poor rim quality, not design. Brakes are similar. The real
problem was shoddy parts and setup on the old bikes everyone
remembers, not design.
IMO, if single pivots were simply as well made and adjusted
as most dual pivots are now, and equipped with good pads,
most people would find them perfectly adequate.
Matt O.
B
>as most dual pivots are now, and equipped with good pads,
>most people would find them perfectly adequate.
So, how do you rate the current Dia-Comps? (sp)
B
(remove clothes to reply)
Chris Zacho The Wheelman
new (old?) things!
Chris Zacho The Wheelman
"That generalization has been invalidated by the move to thinner pads!
It also doesn't apply to centerpulls used with angled rims, nor to
various brake types used with rims with a tall braking surface, such as
the (yuck!) Weinmann concave."
Hey! I Liked my bombproof cancaves! (except for that #%&^#$&
ß©¬ƒçƒº†welded joint, that is)
I just wish they made them for MTB's Strongestb things I've ever ridden!
Chris Zacho The Wheelman
favorite spoke wrench! Also, they often had rather poorly finished
joints.
Sheldon "Liked The 210" Brown "
Ugly? maybe. But then again, so is a Humm-Vee, but it gets the job done!
Anti-aerodynamic? definitely. But who cares on a touring rim?
Aerodynamics don't mean didly-squat at 12mph. I want something that can
take the beating!
Incompatible with your favorite spoke wrench? Well, I don't know which
wrench you use, But my Spokey fit real nicely.
Poorly finished joints? You win there. Never could true out the blip
caused by that welded spot.
Matt O'Toole
"B" <bel...@cs.comclothes> wrote in message
news:20030602195248...@mb-m28.news.cs.com...
> >MO, if single pivots were simply as well made and
adjusted
> >as most dual pivots are now, and equipped with good pads,
> >most people would find them perfectly adequate.
>
> So, how do you rate the current Dia-Comps? (sp)
I haven't seen them. But if they have good pads and don't
flex, they ought to perform well.
Matt O.
A Muzi
news:7c1ndvo0vjv90dl6n...@4ax.com...
They are so Soviet! Heavy, big, ugly and the seams are lumpy. And they
came out in an era of actually _good_ beautiful rims at the same price.
--
Andrew Muzi
http://www.yellowjersey.org
Open every day since 1 April 1971
whitfit
> (aka cosine error) is a major hazard for people unclear on the concept
> because it causes blowouts. Cantilevers, in contrast, "pop under" the
> rim with wear and do not return, leaving the bicycle with no brake.
>
Just curious- In all of my years using cantilevers (okay, not
many,I'm still a young'un, but at least 10 years) I have never
experienced this problem, even with some riding in those famed French
mountains on a touring bike. Has anyone had it happen to them? I've
seen department store bikes which are close, but I think most of that
was because of poor adjustment. Any experience out there?
Whitfit.
Anthony Leverock
Zacho "The Wheelman") wrote:
>Sheldon Brown wrote:
>
>"That generalization has been invalidated by the move to thinner pads!
>It also doesn't apply to centerpulls used with angled rims, nor to
>various brake types used with rims with a tall braking surface, such as
>the (yuck!) Weinmann concave."
>
>Hey! I Liked my bombproof cancaves! (except for that #%&^#$&
>ﾟｩｬ��� welded joint, that is)
>
>I just wish they made them for MTB's Strongestb things I've ever ridden!
>
>May you have the wind at your back.
>And a really low gear for the hills!
>Chris
>
>Chris'Z Corner
>"The Website for the Common Bicyclist":
>http://www.geocities.com/czcorner
Interesting, I never had a problem with the joint! And I have
personally had three Concaves and have worked on maybe a couple of
dozen over the years. Others have told me about problems with bulges
at the joint -- I've checked them and found little to really fret
about, just some tendency to build up crud from some additional pad
wear at the joint, but nothing to be overly concerned about .
- --
Anthony Leverock
Anthony Leverock
wrote:
>> Ouch! I believe the Concave was an outstanding rim - strong and
>> durable -- they made for an excellent wheel. Why do you dis them?
>
>They are so Soviet! Heavy, big, ugly and the seams are lumpy. And they
>came out in an era of actually _good_ beautiful rims at the same price.
Well, OK. I guess you and Sheldon won't be joining the Concave fan
club :) As far as looks, well, I appreciate their interesting looks
as well as other rims of that time, so your point is well taken.
However, as far as weight goes, that doesn't matter much, really - I
guess it depends on the type of riding you used them for. For
commuting they were an outstanding rim (especially the narrower
Concave) and for touring, the wide Concave was excellent. They made
for a durable wheel, able to take a great deal of abuse. As far as
the bulge is concerned...point noted.
- --
Anthony Leverock
jobst....@stanfordalumni.org
>> (aka cosine error) is a major hazard for people unclear on the
>> concept because it causes blowouts [on centerpulls]. Cantilevers,
>> in contrast, "pop under" the rim with wear and do not return,
>> leaving the bicycle with no brake.
> Just curious- In all of my years using cantilevers (okay, not many,
> I'm still a young'un, but at least 10 years) I have never
> experienced this problem, even with some riding in those famed
> French mountains on a touring bike. Has anyone had it happen to
> them? I've seen department store bikes which are close, but I think
> most of that was because of poor adjustment. Any experience out
> there?
If you start with new pads in the retracted position, visually trace
the arc of motion making a circle about the pivot point, you'll see
that the path of the pad can sweep past the lower edge of the rim
without wearing through anything but brake pad material. In dirty wet
conditions, this much wear eaisly occurs. I have seen brake pads pop
under in this manner. I have also seen pads on centerpulls touching
the tire above the rim.
Bluto
Yes, this used to happen; it has happened to me, fortunately not
causing me to crash in the process.
The problem was (is?) that many rim sidewalls slope inward (I remember
specifically some almost-triangular Matrix Iso-C ATB rims from once
upon a time). Mount a narrow rim with inward-sloping sidewalls in a
frame or fork with widely spaced canti bosses, and it's often
difficult to set up the brakes to where the pads won't dive at least
partway down the rim in a hard stop.
Wider rims help, as do concave rim sidewalls and brake booster arches.
Chalo Colina
Matt O'Toole
"Bluto" <chump...@hotmail.com> wrote in message
news:8b4b7de4.03060...@posting.google.com...
I don't know about concave sidewalls -- they seem like a bad
idea. What's really helped is taller sidewalls. Older
common MTB rims like the Mavic 231 had really short
sidewalls that were barely big enough for a brake pad. If
the pad was the slightest bit misadjusted or overly worn, it
could hit the tire, or dive below the rim.
Back in those days, the first thing I'd do is ditch the
stock Shimano straddle setup, and run the cantilevers as
vertical as possible, with the pad posts as close to 90
degrees as possible. Another reason V-brakes have been
successful is that they've kept this geometry.
Matt O.
Sheldon Brown
> I don't know about concave sidewalls -- they seem like a bad
> idea. What's really helped is taller sidewalls. Older
> common MTB rims like the Mavic 231 had really short
> sidewalls that were barely big enough for a brake pad. If
> the pad was the slightest bit misadjusted or overly worn, it
> could hit the tire, or dive below the rim.
This problem is particularly exacerbated when wide tires overhang the
edges of narrow rims.
> Back in those days, the first thing I'd do is ditch the
> stock Shimano straddle setup, and run the cantilevers as
> vertical as possible, with the pad posts as close to 90
> degrees as possible.
That's not a good idea. It drastically reduces the mechanical advantage
of the brake, and it doesn do anything to solve the arc-swing problem,
because the brake shoe is still hitting the same rim, and rotating
around the same pivot point.
> Another reason V-brakes have been
> successful is that they've kept this geometry.
That's comparing apples and locomotives.
See: http://sheldonbrown.com/cantilever-geometry.html
Sheldon "Keep 'Em Wide" Brown
+------------------------------------------------+
| An infallible method of conciliating a tiger |
| is to allow oneself to be devoured. |
| --Konrad Adenauer |
+------------------------------------------------+
Pete Geurds
>caused by that welded spot.
>
>
Block sanding with emory cloth works well.
Then just scuff anodizing off when you're happy with joint.
(brake pads are going to wear it off anyway)
The flat spot would be tougher.
Pete Geurds
Douglassville, PA
Mark McMaster
> Mike S-<< Just like the "Bullseye" cranks that Shimano is bringing out this
> year for
> D/A and XTR...
>
> And altho I sometimes 'like' to slam shimano for some of what they do, they are
> responsible for many improvemnets that have brought people back to bikes and
> kept them there, like lever mounted click shifting. Tremendous improvers, not
> inventors tho.
This seems to mirror a common stereotype for Japanese
industry and product design. And like most stereotypes, it
is really just thinly veiled racism.
When you get right down to it, Shimano has done a hell of a
better job at inventing new component designs than your
favorite component company (Campagnolo) has in the last
twenty years.
In the past decade or two most of Campagnolo's "new" ideas
have been complete dogs (can anyone say Synchro shifting or
Delta brakes), and their best efforts have simply been
copies of Shimano designs (dual pivot brakes, two pivot
slant parallelogram derailleurs, sprockets with shifting
ramps, chainrings with shifting pins, etc.) or variations on
a Shimano theme (cassette freehubs, dual control shifters,
clipless pedals).
So, if you want to label Shimano as simply design improvers,
you'd have to label Campagnolo as design plagarizers.
Mark McMaster
MMc...@ix.netcom.com
Qui si parla Campagnolo
is really just thinly veiled racism.
oh please......
<< When you get right down to it, Shimano has done a hell of a
better job at inventing new component designs than your
favorite component company (Campagnolo) has in the last
twenty years.
As I have stated but they didn't 'invent' the rear der or shifter or crankset
or brakeset, they improved on an existing design...
And looking at shimano in 1982, well they didn't really start improving the MTB
setup until about 1985/6...
<< So, if you want to label Shimano as simply design improvers,
you'd have to label Campagnolo as design plagarizers.
And I do. I guess that sound is the point zooming over your head.
Campagnolo has had some current small designs that are unique and quite good,
like QR at the lever but they are copiers extrodinaire, I have never said they
weren't but Mr shimano didn't 'invent' the quick relase hub, Mr Campagnolo did,
etc.
The Japanese, taught by Mr Drucker, have evolved into some of the the best
business men and one of the most innoivative industrial bases in
existence(watch out for Korea tho). They have the ability to see a design,
improve it and then market it quickly. The car industry is the best example.
BUT saying that they improve but not invent is hardly racist, it is just the
way it is. In may ways, all of industry is lke this, everywhere. Whan was the
last really large 'invention'???
Fintone Qbassi
not Shimano.
Am I wrong?
Mark Gordon
Noblesville
"Mark McMaster" <MMc...@ix.netcom.com> wrote in message
news:3EE15BAB...@ix.netcom.com...
Matt O'Toole
"Qui si parla Campagnolo" <vecc...@aol.com> wrote in message
news:20030607100044...@mb-m03.aol.com...
Things might (and do) appear this way to the casual oberver but I can assure you
it's not the case. Japan and Japanese companies are full of incredible
inventors and innovators. Honda is, and always has been, at the forefront of
automotive engineering. Look at their success in F1 racing, their innovative
and successful engine designs, their very elegant hybrid drivetrains, and most
of all, their ability to bring these projects to the showroom within 18 months
of inception. Wow. This is not mere tweaking, but innovation at a level and
pace only dreamed of in Detroit or Munich. Look at companies like Sony and
Panasonic, who have, for the last 40 years, designed and defined every new
electronic gadget that has come along, from the transistor radios of the 60s, to
the Walkmans of the 80s, to the cell phones of today. Who is inventing and
developing the new LCD and plasma TVs? Not Americans... Look at NTT DoCoMo,
and all the weird and wonderful things Japanese kids do with their cell phones.
Look at their fashion, their food, their pop culture. These people are cutting
edge.
Getting back to bikes, look at all the interesting designs they have in Japan --
comfort bikes, commuter bikes, folders. Not all of them are winners, but the
Japanese are the ones with the vision and guts to break the mold and try
something new.
But perhaps it's unfair to use the bike industry as an example anyway. After
all, bikes are incredibly simple machines. No genius required.
Matt O.
Chris Zacho The Wheelman
>In the past decade or two most of
>Campagnolo's "new" ideas have been
>complete dogs (can anyone say Synchro
>shifting or Delta brakes),
No, but I can say rally touring derailer (satisfied, Sheldon?)
>and their best
>efforts have simply been copies of
>Shimano designs (dual pivot brakes, two
>pivot slant parallelogram derailleurs,
Funny, I thought that Sun Tour came up with the slant paralell
design...?
>sprockets with shifting ramps,
Which severly limit customized gearing, and, IMHO, perfom little better
than UniGlide does.
>chainrings
>with shifting pins, etc.) or variations on a
>Shimano theme (cassette freehubs, dual
>control shifters, clipless pedals). "
Not knockin' Shimano totaly, but they have come up with a few lemons
themselves.
Mark McMaster
> I thought it was SunTour who "invented" the slant paralelogram rear design,
> not Shimano.
Indeed they did, and were quick to patent it. Their first
derailleur with this feature appeared in 1964, and Shimano
did not adopt it until the patent expired. However, the
Shimano derailleur had an additional feature not found on
the Suntour version - dual spring pivots. The original
Suntour slant parallelogram derailleurs had a fixed upper
pivot (they added an active top pivot spring only later).
(Historical note: Simplex patented the first dual spring
pivot derailleur in 1944. Shimano started using dual spring
pivots in 1967).
By the time Campagnolo started making derailleurs with their
current configuration, they were basically functional copies
of Shimano derailleurs.
Mark McMaster
MMc...@ix.netcom.com
Ryan Cousineau
Chrisz...@webtv.net (Chris Zacho "The Wheelman") wrote:
> Mark McMaster wrote:
>
> >In the past decade or two most of
> >Campagnolo's "new" ideas have been
> >complete dogs (can anyone say Synchro
> >shifting or Delta brakes),
> No, but I can say rally touring derailer (satisfied, Sheldon?)
> >and their best
> >efforts have simply been copies of
> >Shimano designs (dual pivot brakes, two
> >pivot slant parallelogram derailleurs,
> Funny, I thought that Sun Tour came up with the slant paralell
> design...?
> >sprockets with shifting ramps,
> Which severly limit customized gearing, and, IMHO, perfom little better
> than UniGlide does.
Your opinion is yours, but believing that Hyperglide isn't a vast
improvement over Uniglide belies my own experience with both systems.
I have two friction-shift bikes, one a Uniglide (twist-tooth) bike I've
had since new, the other retrofitted with a Hyperglide 6v freewheel
replacing the SunTour (no-Glide?) original.
The shifting quality vastly better on the Hyperglide, so much that I
hardly miss indexing on that bike.
> Not knockin' Shimano totaly, but they have come up with a few lemons
> themselves.
Yes, but they balanced out Positron and 10 mm chain by introducing
really good indexing and great shifting.
--
Ryan Cousineau, rcou...@sfu.ca http://www.sfu.ca/~rcousine
President, Fabrizio Mazzoleni Fan Club
A Muzi
> > > this year for D/A and XTR...
> > Qui si parla Campagnolo, perhaps flippantly wrote maybe before
thinking about it very much:
> > > And altho I sometimes 'like' to slam shimano for some of what they do,
> they are
> > > responsible for many improvemnets that have brought people back to
bikes
> and
> > > kept them there, like lever mounted click shifting. Tremendous
improvers, not
> > > inventors tho.
> "Mark McMaster" <MMc...@ix.netcom.com> perspicaciously wrote in message
> news:3EE15BAB...@ix.netcom.com...
> > This seems to mirror a common stereotype for Japanese
> > industry and product design. And like most stereotypes, it
> > is really just thinly veiled racism.
> >
> > When you get right down to it, Shimano has done a hell of a
> > better job at inventing new component designs than your
> > favorite component company (Campagnolo) has in the last
> > twenty years.
-snip examples-
". . . two pivot slant parallelogram rear derailleurs. . .
> > So, if you want to label Shimano as simply design improvers,
> > you'd have to label Campagnolo as design plagarizers.
"Fintone Qbassi" <fin...@hotmail.com> wrote in message
news:e82e4e4e9b003e4169337f5c40f937ee@TeraNews...
> I thought it was SunTour who "invented" the slant paralelogram rear
design,
> not Shimano. Am I wrong?
You're right. The slant parallelogram was Maeda Industries (SunTour) and
the currently-used balanced dual pivot spring concept was by Lucien Juy (
Simplex).
But I recall a trade show where Shimano's new slant parallelogram rear
derailleurs were all under wraps the first day because one of the relevant
patents expired at midnight that evening. AFAIK Shimano produced the first
modern derailleur with both designs together which is nearly ubiquitous
nowadays - everything from Alivio and SunRace to Record ( OK, neither
Tourney, Sugino, ZAP nor ESP, but still).
But I think this is getting a bit silly. Shimano has producd some
impressively clever true innovation as have many others. They have also
proudly debuted crap that was quietly dropped the next season, as has
Campagnolo. Is there a point here? I doubt it.
Bluto
> When you get right down to it, Shimano has done a hell of a
> better job at inventing new component designs than your
> favorite component company (Campagnolo) has in the last
> twenty years.
>
> In the past decade or two most of Campagnolo's "new" ideas
> have been complete dogs (can anyone say Synchro shifting or
> Delta brakes), and their best efforts have simply been
> copies of Shimano designs
Some of the things brought to market by Shimano and not copied by
Campagnolo:
Biopace-- nah, too easy; not dumb enough to really count. How about:
AX pedals
Positron
10mm pitch chain, rings, sprockets
lollipop straddle cables
front freewheel
2mm cables/6mm housing
automatic shifting
stamped-on, non-replaceable cassette freehub bodies
riveted chainrings
4-arm cranks
top swing front derailleurs
cast-plastic-over-steel cranks, brakes, levers, pedals...
"anti-lock", anti-stop brakes
130mm/92mm cranks
Along with plenty of dumb stuff that Campy _did_ copy: 7sp shifters
that won't work w/6sp, 8sp that won't shift 7, 9sp that won't shift 8.
One-time-use chain links. Powdercoated components.
I could go on, but why? For every genuine engineering development
that Shimano have offered the market, there is an assortment of
pointless geegaws that never should have seen the light of day. They
have such a prolific history making stupid junk to answer nonexistent
questions that Campagnolo have not a prayer of catching up in that
regard.
Chalo Colina
P.S. Campy parts are overpriced and weak, too.
Jasper Janssen
wrote:
>The car industry is the best example.
>BUT saying that they improve but not invent is hardly racist, it is just the
>way it is. In may ways, all of industry is lke this, everywhere. Whan was the
>last really large 'invention'???
So everything is just improvements and nobody's really innovating
anything? Mr Bell Labs (of transistor and other fame) and the boys at ARPA
and Tim Berners-Lee (of the internet and thw world wide web fame,
respectively) might want a word.
Jasper (I could go closer to today, but it's harder to see which
particular invention will impact our future lives most)
Qui si parla Campagnolo
anything?
'Everything' and 'nobody' and 'anything' are big words..
Most things these days seem to be improvments on existing designs, not geniune
inventions. The auto was just an improvement of the horse drawn cart, but the
internal combustion engine was an invention, IMO.
Jasper Janssen
wrote:
>jasper-<< So everything is just improvements and nobody's really innovating
>anything?
>
>'Everything' and 'nobody' and 'anything' are big words..
So why use them? ('All of industry' and 'everywhere' being the ones that
you used)
> Most things these days seem to be improvments on existing designs, not geniune
>inventions. The auto was just an improvement of the horse drawn cart, but the
>internal combustion engine was an invention, IMO.
If you wanna go that way, the IC engine is basically just an improvement
on the steam engine, except using chemical explosions for pressure rather
than externally generated steam. The differences between a twostroke,
fourstroke or diesel internal combustion are no larger than the difference
between any of them and a modern steam engine or a Wankel rotary engine.
And a primitive steam engine was first invented by the ancient greeks
several centuries before Christ. For that matter, Volta in the 16th
century invented lead/copper-acid batteries, but saying there have been no
inventions in the field of batteries since then, as everything is just
improvements on that design, is stupid.
When you look at the world your way, it has to be a sad, sad place where
nobody can ever think of anything new.
Jasper
jobst....@stanfordalumni.org
>> So everything is just improvements and nobody's really innovating
>> anything?
> 'Everything' and 'nobody' and 'anything' are big words..
I think those words fall directly out of your claim that there are no
inventions because there is nothing new in technology.
> Most things these days seem to be improvements on existing designs,
> not genuine inventions. The auto was just an improvement of the
> horse drawn cart, but the internal combustion engine was an
> invention, IMO.
That sounds like sour grapes. Invention is the process of applying
observed needs with an appropriate mechanism to perform the task, be
that by combining previously unrecognized synergies or a claw hammer
that can pull nails as well as drive them. The Wright Brothers
combined a special version of an internal combustion engine, with an
appropriate flying machine to make a powered aircraft with horizontal,
vertical, and turns controls that no one had put together before.
That was a large series of inventions that required great scientific
learning and practical skills.
You are stretching "improvement to existing designs" to extremes.
Similarly a cell phone is only a better two paper cups with a string
between them in that respect. CD's are more than an extension of
Edison's wax cylinders.
Your complaint sounds vaguely similar to those who believe that garage
mechanics know more about cars than the engineers that design them.
Qui si parla Campagnolo
where
nobody can ever think of anything new.
Sad is a big word...I guiess you are still upset at being called
french...AMF......
Qui si parla Campagnolo
inventions because there is nothing new in technology.
I try not to use absolutes on this NG....
I think I said 'most'..don't think I said 'no' inventions or 'nothing' new...
<< You are stretching "improvement to existing designs" to extremes.
Okay....but, but, but...oh well...
<< Your complaint sounds vaguely similar to those who believe that garage
mechanics know more about cars than the engineers that design them. >>
geez. I'm not complaining...just talkin' about inventions and how they apply to
bikes...
BUT rmember that the Wright Bros were 'garage mechanics', not engineers...
Jasper Janssen
wrote:
>BUT rmember that the Wright Bros were 'garage mechanics', not engineers...
Actually, to steer this back on topic, they were bike wrenches. Not car
garage workers.
Jasper
Peter Cole
>
> BUT rmember that the Wright Bros were 'garage mechanics', not engineers...
Nothing could be further from the truth.
Mark McMaster
>
>
The Wright brothers may have also been bicycle shop
proprietors, but they were some of the finest engineers of
their age - especially in their chosen field of aeronautics.
They studied the latest scientific research in the field,
created experimental laboratory models and made thorough and
precise measurements to further scientific knowledge as
necessary, and used sound engineering methodology to
transform scientific theory into practical applications.
For example, they performed many tests of airfoil shapes
with scale models in a wind tunnel before building full
scale prototypes. They were far from the "tinkerers" that
you imply. And if you can't tell the difference ...
Mark McMaster
MMc...@ix.netcom.com
Qui si parla Campagnolo
<< They studied the latest scientific research in the field,
created experimental laboratory models and made thorough and
precise measurements to further scientific knowledge as
necessary, and used sound engineering methodology to
transform scientific theory into practical applications.
But they were not formally trained engineers, correct?? College trained
engineers..
<< They were far from the "tinkerers" that
you imply. And if you can't tell the difference
Geez, you can imply a lot from a 11 word sentence..
Ryan Cousineau
vecc...@aol.com (Qui si parla Campagnolo) wrote:
> mark-<< but they were some of the finest engineers of
> their age - especially in their chosen field of aeronautics.
>
>
> << They studied the latest scientific research in the field,
> created experimental laboratory models and made thorough and
> precise measurements to further scientific knowledge as
> necessary, and used sound engineering methodology to
> transform scientific theory into practical applications.
>
> But they were not formally trained engineers, correct?? College trained
> engineers..
Two things are worth pointing out:
1) Regardless of their educational background, the Wrights took an
exceedingly methodical and scientific ("engineering") approach to the
design and construction of their airplane. They built numerous gliders
to test their ideas, the already-mentioned wind tunnel, etc.
2) There were very few schools with an aeronautical engineering
departments at the turn of the century. Like none. The Wrights did the
best thing under the circumstances, which was do the research,
correspond with the experts in the field (they talked to Otto Lilenthal
and studied his work with gliders), and figured out the math.
3) (bonus thing) They lived in an era, where, for better or for worse,
formal education was rarer, and self-taught students could and did
regularly become experts and great contributors to scientific knowledge.
Nowadays engineering schools are easier to find, easier to get into, and
more accessible to more people (in the developed world, at least).
4) (I never was good at math) Unlike most posters here in rbt (including
myself), when confronted with the technical details of an engineering
problem in their field, they would understand the problem, the
associated math, and the ramifications of the problem at a level
equivalent to any engineer. They used the Scientific Method carefully,
methodically, and in a way that would have invited publication in
research journals had they been so inclined (maybe they were; I don't
know) It is this engineering style and aptitude that separates the
Wright brothers from most of the people in this ng, not their
Latin-inscribed wall candy.
> << They were far from the "tinkerers" that
> you imply. And if you can't tell the difference
>
> Geez, you can imply a lot from a 11 word sentence..
>
> Peter Chisholm
--