[CR]The brake wars...

(Example: Framebuilding:Technology)

Date: Fri, 08 Feb 2008 20:55:33 -0500
From: "Harvey Sachs" <hmsachs@verizon.net>
To: classic Rendezvous <classicrendezvous@bikelist.org>
Subject: [CR]The brake wars...

I've been pretty quiet about the Great Debate re Campagnolo brakes, Weinmann CPs, &c, and would now just offer a couple of observations that may be useful or helpful to some:

1) What I think was the first generation Weinmann 999 CP had its posts rivited to the mounting plate. The aluminum plates tend to crack; be careful if you use one. Somewhere I have pix if someone wants to post them. Meanwhile, I'd love a spare for my '65 Paramount, for which they seem to be correct, if not necessarily safe.

2) Any brake can be made to work badly with stupidities like excess friction in the cables (not trimming the housing ends, etc). So, what's the difference among properly set-up brakes?

3) My strong sense is that the most important variable is the total mechanical leverage of caliper and lever. At one extreme, the Universal lever with Universal 68 SP moves the brake pad the most, per unit lever movement, that I've ever measured. Lots of movement --> little leverage --> very stiff feel, but relatively little pressure on the rim. And vice versa. MUCH less pad travel with almost any centerpull, which is why QRs of some sort are more important. It took a bit of time to set up a jig to actually measure lever travel, but the range was a factor of two, or more, just among standard, non-aero levers (if I recall correctly).

4) Only then do I start thinking about differences among brake pads.

5) LOTS of brakes are "good enough," but there are quality differences, too. I took apart a Weinmann SP (500, I think) and a Universal 68 SP a week or so ago for lubing, etc. It appeared, at least for the Universal, that the spindle hole was just cast in, but perhaps leaned a bit. In contrast, the Campy is a much higher precision item, with decent surfaces. Of course, the bearings are almost entirely the washers and surfaces between the arms (etc), so the spindle is there as fulcrum mostly, but it is interesting to see the differences.

6) In the sp discussion, I recall little about the early Shimano SP. The QR is not as sophisticated as Campy's, which will work at intermediate positions, but I find the Shimano much more pleasant to use, perhaps because it still has good feel, but seems to require less force than the Campy. I have less experience with the Shimano than with the Campy, but I sure don't find the Campy to be clearly superior.

I guesss I've gored enough oxen for one evening.

harvey sachs
mcLean va.