Re: [CR]Why normal reach calipers on short reach frames?

(Example: Racing:Jacques Boyer)

From: Douglas R. Brooks <dbrk@troi.cc.rochester.edu>
Subject: Re: [CR]Why normal reach calipers on short reach frames?
To: rocklube@adnc.com
Date: Fri, 11 Jan 2002 20:52:09 -0500 (EST)
Cc: CaptBike@sheldonbrown.com, classicrendezvous@bikelist.org
In-Reply-To: <3C3F8FEA.553C@adnc.com>


I understand Sheldon's point entirely but my question is that given the power of contemporary brakes, such that long reach brakes like RX100s have stopping power comparable to, say, Dura Ace brakes, are the vast majority of modern brakes made short reach to create _that much more mechanical advantage_? Alas, I see no advantage to the short reachers now that brakes are so much better! I guess race bikes don't need clearances, is that it? Classic content: Is there any reason why classic centerpulls have not made a comeback? They have many advantages as I see it: easy set up, pulling from the center is mechanically simple and distributes the power efficiently, lots of clearance for fenders, so much so that on my Rivendell it is the fork crown, not the brakes that create the limits. With Mathauser pads, even the low end Mafacs work as well as any modern brake I use (DA, Record, Mavic, etc.) Use the NICE Mafacs or whatever and it seems to me they stop as well as you need to stop! Is it tooling? Is it the are just old stuff?

Douglas Brooks who still feels the absence of Photopoint in Canandaigua, NY


> Sheldon,
>
> Pin a silver star on Mr. Sheldon Brown! That is exactly the reason for
> minimizing the brake reach on a racing bike. The same principal applies
> to track frames and tire clearance between the fork crown and the seat
> stay bridge.
>
> That Sheldon, such a fountain of information!
>
> Brian Baylis
> >
> > Lee Berg wrote:
> > >I have noticed a number of '70s bikes, whose frames appear to have been
> > >made for short reach calipers, sporting normal reach calipers with pad
> > >holders in the tops of the slots. Were normal reach calipers installed
> > >due to some desired mechanical property of this arrangement?... or due
> > >to a some extended shortage of short reach calipers?... or was it just a
> > >fashion of the time?... Or...???
> >
> > Short reach calipers generally have a reach range of 39-49. Long
> > reach is usually 47-57. (Talk of "normal" reach is likely to be
> > confusing, and I'd urge everybody to purge this ambiguous term from
> > their vocabulary.)
> >
> > A caliper brake has its greatest mechanical advantage when the pads
> > are high up the arms, close to the pivot. Back when long reach was
> > the "norm" a conscientious frame builder building a high performance
> > bike would locate the bridge and crown to maximize the braking
> > mechanical advantage. Especially, the old Campag single pivots had
> > such poor braking that this was a very nice touch.
> >
> > You may also see this on bikes made to work with both 630 mm (27
> > inch) clinchers and 622 (700c) tubulars. When the larger wheels were
> > installed, the shoes should be near the tops of the slots.
> >
> > Sheldon "Stop!" Brown
> > Newtonville, Massachusetts
> > +----------------------------------------------------------------+
> > | The thing about the cold is that you can never tell how cold |
> > | it is from looking out a kitchen window. You have to dress |
> > | up, get out training and when you come back, you then know |
> > | how cold it is. -Sean Kelly |
> > +----------------------------------------------------------------+
> > Harris Cyclery, West Newton, Massachusetts
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> > http://harriscyclery.com
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