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Old 09-08-09 | 03:55 PM
  #23  
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DannoXYZ
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Joined: Jul 2005
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From: Mesa, AZ

Bikes: Moots RCS, tandem, beach-cruiser, MTB, Specialized-Allez road-bike, custom track-bike

Originally Posted by Mark A
However, I noticed a weird effect - the brake does NOT scream when the front wheel turns in REVERSE. This makes me think the problem lies outside the pad/rim interface: could it be play in the attachments from the calipers to the fork, for example?
Toe-in is always looking forwards in the direction of travel. If you're looking at the front brake by standing in front of the bike, the pad-edge that must be closer is at the REAR (furthest from the fork). It would look like TOE-OUT if you're facing backwards towards the bike.


What kind of brakes? Caliper or cantilever? As already mentioned many times, play in the brake-arms is the main cause of the problem. Toe-ing in the pads only deals with the effect (squeal) of the problem, but don't actually do anything to fix it. When the pads wear parallel to the rims, the squeal will start yet again.

I've found that removing as much play as possible but not binding the brake-arms to be the longest-term solution (actually improves braking-feel, modulation and power as well by allowing you to use most of the brake-pad, rather than just the tip).

For single-pivot caliper-brakes, there's usually is an adjustment-nut and locknut at the end of the pivot-bolt. Disassemble the brake and grease the mating surfaces on the arms and washers. Re-assemble and adjust the adjustment-nut so that the arms bind just slightly. Then use two wrenches to loosen the adjustment-nut up into the locknut that you're tightening down. This relaxes the adjustment slightly and frees up the slight binding on the caliper to give smooth action with no play.

On dual-pivots, there is typically a stack of thin washers under the mounting bolt for each arm. You can remove a thin washer at a time until there's no play.

For cantilevers, the pivot-post for the brake-arm can be filed shorter so that the brake isn't sliding up and down the post. Depending upon the brake, this post can be the one on the bike itself (early models), or is the sleeve that slides over the mounting post on later models.

Once you remove as much play as possible, you'll find that slight toe-in is all you need.
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