Bicycle Mechanics - Excessive toe-in on one brakepad

hey all

(sorry, I meant for this to go in the Mechanics forum...)

just bought a new pair of Shimano Deore brake pads, for a Linear Pull caliper setup. As a novice, I carefully followed the Park Tools 'Big Blue Book' instructions to install the new pads. The right pad is set very nicely. However, the left pad is very excessively "toed-in" -- i.e., the front of the pad is rubbing the rim, while the back is not even close. The pad is at probably a ~15-20 degree angle away from the rim.
What might I be doing wrong here? I've re-adjusted the nuts/washers on that side, several times, but the pad ends up in the same (mis)alignment. Would installing the pad with a shim at the front help? Is it possible that the pad is defective / warped?


thanks much,

try try again!
loosen the nuts/washers on that side even more than you did before and try to adjust the angle of the pad. If you still can't fix the pad angle, then squeeze the brake lever while that pad is loose. That should flatten it out. You can stick a small coin under the appropriate side prior to squeezing to achieve a reasonable toe-in.

try try again!

heh... good advice. I got it much closer on the sixth (or so) try. still a bit more angled than I'd like (I think), but I'm guessing it'll flatten out some over time..

thanks for the response...

just bought a new pair of Shimano Deore brake pads, for a Linear Pull caliper setup. As a novice, I carefully followed the Park Tools 'Big Blue Book' instructions to install the new pads. The right pad is set very nicely. However, the left pad is very excessively "toed-in" -- i.e., the front of the pad is rubbing the rim, while the back is not even close. The pad is at probably a ~15-20 degree angle away from the rim.
What might I be doing wrong here? I've re-adjusted the nuts/washers on that side, several times, but the pad ends up in the same (mis)alignment. Would installing the pad with a shim at the front help? Is it possible that the pad is defective / warped?

Hmmm. Sounds akin to the all-to-common saddle angle problem to me.

With saddles the problem is that guys try repeatedly to loosen the clamp bolt and reposition the saddle only to have it resume the exact same angle. The cause is that the bottom part of the saddle clamp is stuck and doesn't move even after the clamp is loosened. The cure is to knock the bottom part of the clamp loose, reposition the saddle and retighten the bolt.

I'm wondering if the same thing has been happening with your brake. The next time that you loosen the bolt, make sure that the spherical washers are knocked loose before you try to reposition the pad. My bet is you'll find one of those washers is stuck.

Anytime you install pads do this: 1) Position the pad where you want it on the rim. Typically, you want a toe in setup. To get this, put a business card on the rear of the brake pad, making sure it is ONLY ON THE REAR part. 2.) Hold the corresponding brake lever as tight as you can and tighten down the nut holding the pad on. Repeat for each pad.

I've been running into this a lot lately. It seems like some of the washers aren't smooth enough for the pads to wiggle on the concave/convex surfaces. A little grease anywhere those washers touch seem to make adjustment much easier.

The Park book might already have a similar tip, since the instructions on the Park web site do (they recommend a piece of rubber band), but I just toed my pads with little rings cut from an old tube. Better than a business card or a coin, I think because you just slip them over the end and don't have to hold them in place.

My approach to your problem would be similar to what's been said: loosen up a lot, wiggle everything around a bit (maybe twist the concave/convex washers in different directions so they can't sit exactly the way they were doing before), then hold the pad against the rim, put tension on the cable (I tie something around the lever. there might be a more sensible way), and tighten.

I've been running into this a lot lately. It seems like some of the washers aren't smooth enough for the pads to wiggle on the concave/convex surfaces. A little grease anywhere those washers touch seem to make adjustment much easier.

+1 Much easier with the concave/convex surfaces greased.

Funny, I've rarely had an issue with toe-in on V-brakes. Read: V-brakes by design/function require little toe-in if any at all.

What if you swap the pads to the opposite sides?

Funny, I've rarely had an issue with toe-in on V-brakes. Read: V-brakes by design/function require little toe-in if any at all.

You've clearly never had to assemble lots of low end bikes with v-brakes. If your statement were true, you'd be saving me a heck of a lot of aggravation.

You've clearly never had to assemble lots of low end bikes with v-brakes. If your statement were true, you'd be saving me a heck of a lot of aggravation.

You are right about that! I'm not an assembler of 'lots of low end bikes with V-brakes". My experience only includes higher-end with XT or XTR. Sorry.

You are right about that! I'm not an assembler of 'lots of low end bikes with V-brakes". My experience only includes higher-end with XT or XTR. Sorry.

You lucky *******. The low end v-brakes either have a lot of play in them (causing squealing), the brake pads are shyte (causing squealing) or the rims are shyte (causing squealing).

Argh.

You lucky *******. The low end v-brakes either have a lot of play in them (causing squealing), the brake pads are shyte (causing squealing) or the rims are shyte (causing squealing).

Argh.

Worst of all the lower end Shimano V-brake offerings are hugely better and can't cost more than a few pennies more. ProMax sucks! Why do those things even exist?

Worst of all the lower end Shimano V-brake offerings are hugely better and can't cost more than a few pennies more. ProMax sucks! Why do those things even exist?

Oh trust me, these are lower end than promax.

Oh trust me, these are lower end than promax.

How do you guys rate the Tektro line?

I recently installed some Tektro's on my GF's commuter, particular model made with slightly longer arms to clear fenders, what a good idea. The Tektros seem to perform just fine, look similar to low-end Shimano.

[QUOTE=kenhill3;6472402]How do you guys rate the Tektro line?[QUOTE]

I've gotten inconsistant results with Tektro linear pull brakes. Back in '97 or '98 I had a real good opinion of them but it gradually diminished over the years. I suspect their quality control is iffy and it depends a lot on the individual set that you get.

I don't have enough experience with Tektro caliper brakes to have formed an opinion but I've heard a lot of good reviews about them. My issue with them is they're roughly the same price as Shimano so why take the chance?

+1 Much easier with the concave/convex surfaces greased.

Thanks again for all the responses. I do think the grease helped on the final (successful) try, as did just messing around more with the nuts & washers.

Btw, I couldn't swap sides because the pads are specifically-marked for L & R, and designed off-center (i.e., more pad behind the bolts than in front).


cheers,

How do you guys rate the Tektro line?

I recently installed some Tektro's on my GF's commuter, particular model made with slightly longer arms to clear fenders, what a good idea. The Tektros seem to perform just fine, look similar to low-end Shimano.

Their v-brakes are sort of not so great. Their dual pivot short, medium, long reach calipers are excellent value - good quality, good price