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-   -   Cantilever brake pad installation hell! (https://www.bikeforums.net/bicycle-mechanics/370631-cantilever-brake-pad-installation-hell.html)

destro713 12-14-07 12:24 AM

Cantilever brake pad installation hell!
 
I just tried to install a pair of rear cantilever brake pads for over three hours and failed.

My problem is that my brakes don't pull the pads straight in from the sides. They pull with a sort of off-center curving or rocking motion, so the front tip of the pad has a lot more travel to it than the back tip of the pad. Because of this, I have to position them so the backs of the pads are much closer to the rim than the fronts. These are Kool Stop Eagle 2 pads, which have a little lip thing that juts out a little bit at the rear part of the pad. They look like this:

http://www.koolstop.com/brakes/Eagle2Threaded.jpg

That lip makes it so I have to put the pads at a sharper angle, which means the front tips of the brake pads are very far from the rim when the brakes are resting. It takes so much cable slack to allow for that big angle that I basically have no rear braking power.

Here's a 12-second video that shows what I'm talking about.

I've tried to adjust this a zillion different ways but I can't get it working. If I change the angle of the pads so that the fronts aren't so far from the rim when the brakes are resting, the rocking motion makes the pads strike the rim unevenly. If I tighten the slack even just a little bit to give myself some more braking power, the lip at the back end is constantly rubbing against the rim.

So I guess what I want to know is... does any of this information make sense? Is there a way I can go about solving this? And, are all cantilever brakes like this, or are there better ones that pull straight?

wroomwroomoops 12-14-07 01:12 AM

I saw the video - you set a new standard in illustrating your situation, and that's super-commendable! Hats off to you!

I don't see very clearly if the rear tip, the one closer to the rim, is touching the rim when "resting"? If not, briefly, you don't have a problem, but test whether you have enough stopping power before you go bombing down a hill. And to answer your last question: not all cantis are like this.

destro713 12-14-07 02:55 AM

I spent another hour adjusting them and bought myself a bit more stopping power... but if there are better cantilever brakes than this, that don't swivel as they contract, I think I'm gonna buy myself a pair in the spring. These things are a pain. I guess that's what I should expect out of stock early-90's MTB components though.

cs1 12-14-07 03:32 AM

From the pic of the pad, I don't see the beveled washers. There is a washer, or two, that allow you to change the toe-in on the pads. That's all you need. The travel of the arm appears to be moving perpendicular to the axis of the wheel. If the brake arm wasn't moving at 90 deg then you would have a problem.


Tim

wroomwroomoops 12-14-07 03:33 AM


Originally Posted by destro713 (Post 5806813)
I spent another hour adjusting them and bought myself a bit more stopping power... but if there are better cantilever brakes than this, that don't swivel as they contract, I think I'm gonna buy myself a pair in the spring. These things are a pain. I guess that's what I should expect out of stock early-90's MTB components though.

Well, my old Kona Kilauea has stock early 90's cantilever brakes that worked like a charm :D

jgedwa 12-14-07 09:49 AM

Adjusting canti brakes is sometimes really hard. It is one of my least favorite jobs.

I do not have a great solution to your problem, but here are some crazy ideas:

-use a file to get rid of that rear lip, so you can set the brakes closer to the rim.
-install the pad backwards so that the lip is in front.
-set it up as is. go to the top of the mountain and ride down dragging the brakes the whole way. they will wear into the correct profile needed.

jim

destro713 12-14-07 10:15 AM


Originally Posted by cs1 (Post 5806856)
From the pic of the pad, I don't see the beveled washers.

Mine are actually unthreaded. I just included the pic to show the lip.

I have no mountain to ride down but I'll run some errands today and see if things improve after a bit of break-in. I haven't had a chance to test my most recent adjustments, because I finished them at 3AM.

JanMM 12-14-07 10:34 AM

Recently replaced the canti's on my older Cannondale hybrid singlespeed with Forte V-brakes. So very much easier to install and adjust!

Mr. Underbridge 12-14-07 10:39 AM

I can't view the video, but cantis should definitely not swivel as they close. Is it possible the brake bosses are bent, or the cantilevers installed incorrectly on the bosses?

destro713 12-14-07 10:46 AM

I can't see how they could be installed any other way. And I assume they're not bent because they behave identically.

AndrewP 12-14-07 11:21 AM

You need to replace those cantis with Avid Shorty6 or Tektro Oryx, which have the threaded post on the pads. You can probably get used ones from your LBS cheap, left over from 'upgrades' to Vs. They are even easier to adjust if you install them with a yoke and straddle cable instead of the current Shimano branch.

destro713 12-14-07 11:34 AM

Yes. And I also need to replace the entire 200GX drivetrain that gives me multiple chain skips per ride.

mikepoole 12-14-07 11:38 AM


Originally Posted by Mr. Underbridge (Post 5808265)
I can't view the video, but cantis should definitely not swivel as they close. Is it possible the brake bosses are bent, or the cantilevers installed incorrectly on the bosses?

I could see the video, but agree that they shouldn't swivel... is there a bushing missing inside all the arms? They look like they have a lot of play as seen in your video...

wroomwroomoops 12-14-07 06:48 PM

Well, if we're talking replacing, then why not go with V-brakes? That's what I put on that Kilauea I mentioned before. I did that NOT because I wasn't satisfied with the stopping performance of the cantis ('cause I was, very satisfied), but because my heel kept hitting, albeit slightly, the left arm of the rear cantilever. So there I went V-brake. In front I still have cantis.

erader 12-14-07 08:50 PM


Originally Posted by wroomwroomoops (Post 5811344)
Well, if we're talking replacing, then why not go with V-brakes? That's what I put on that Kilauea I mentioned before. I did that NOT because I wasn't satisfied with the stopping performance of the cantis ('cause I was, very satisfied), but because my heel kept hitting, albeit slightly, the left arm of the rear cantilever. So there I went V-brake. In front I still have cantis.

so what are you using for brake levers :eek:.

ed rader

wroomwroomoops 12-14-07 10:30 PM

I didn't need to replace my brake lever. Works fine with the V-brake.

nitropowered 12-14-07 10:34 PM

You got some major play in the pivot, or the canti boss is bent. Its deal with it or replace time.


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