Bicycle Mechanics - Adjusting centerpull brake pads
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I recently bought a late-70's road bike which has Dia-Compe centerpull brakes. I put on some Kool Stop "Continental" brake pads, which are a bit better than the original pads.
However, I can't get the pads to the hit the rim at the correct angle. Due to the angle of the brake arms, the pads tend to hit with the top edge first, and both pads are toed out a fair amount. As a result, the brakes squeal like crazy, and the braking, while decent, is not as good as I'm used to with dual-pivot brakes.
There doesn't seem to be any way to adjust the alignment of the pads relative to the brake arms -- they just bolt on without any of the fancy hardware that newer-style pads seem to have, so they are always perpendicular to the arms.
Is there any way to get the pads properly adjusted on this type of brake? Or did people in the 70's just live with crappy brakes all the time? ;-)
02-08-07, 12:11 PM
first of all do the pads have the same hardware as do v-brake pads? if not you may have to use v-brakes that comes with beveled washers.
when using these pads on these center pull brakes be sure that the thickest washer is on the inside of each brake arm.
when adjusting them to the rim while have the cables intack and the spacers and nut on the pads lose but connected squezze the lever while holding the pad to the rim like you want it the squezze the tight while tighting the nut on each pad.
when you are finished if the brakes squeak the toe the pads in toward the front with a adjustable wrench.
02-08-07, 12:18 PM
Older centerpull brakes often came with pads that had a "slant" - they were thicker at the bottom than at the top. Whereas today's pads (designed for today's brakes) are equal thickness on top and bottom of the pads.
You have two options:
1) get pads that have spherical washer so you can adjust toe-in when bolting the pads
2) file the pads down so that they're angled such that they hit the rim ideally (or just ride in the rain and wait until they get worn down this way "naturally")
Here's a picture of the Brakes with original pads. (I've put new pads on mine and will see about filing them down.)
You can bend those arms slightly to correct for toe-in and the angle of the pads. I've bent a few pairs before, as long as it's just a small amount it's no big deal. Park makes a tool for doing it but I just use an adjustable wrench- take the pads off, clamp the jaw down, hold everything else in place, bend a little. You want the smooth jaws of an adjustable wrench, not a pair of pliers. I wouldn't worry about the angle so much, file it or just let time wear the pads down a bit.
02-08-07, 01:00 PM
I'm using the Kool Stop salmon Thinline brake shoes (for v-brakes) with my Dia-Compe centerpull brakes, they work great and toe-in is easy because of the spherical washers. When those pads wear out, though, I'll replace them with the cartridge-type shoes that Nashbar sells for about $5 per pair, and will then use Kool Stop salmon cartridge refill pads (for v-brakes) to replace the stock Nashbar pads. The cartridge pads make pad replacement especially easy, because you don't even have to disturb the toe-in adjustment to replace the pads, and the replacement cartridge pads are about half the price of the non-cartridge shoes-
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