Disc Brake Rub (Pads Centered)
I was replacing the pads on my bike when I noticed that I couldn't get the non-drive side pad to center on the front brake. A closer look revealed the pull tab was contacting the fork adapter so the brake was permanently toed in and contacting the rotor(see photos). The pad is fully inserted into the brake.
I could add spacers to the adapter, but that would change where the pads contact the rotor and that doesn't seem right. I have had the bike for 3 seasons and don't remember this problem from before, yet the new pad matches the one I replaced.
Have I done something wrong, do I need to find a different adapter or should I just cut the tab short?
If you replace that pad with the original, does it contact the adapter?
Yes the original pad reinstalled displays the same symptom, though it appears the pad has worn to accommodate the problem. I bought the bike several seasons ago used and it must have worn to suit before I did so.
Are you using Avid brake pads or aftermarket?
See if you can bend it with pliers and a vise. I'd find a way not to grab onto the brake friction material.
Yes, but the original and the aftermarket pads are Avid pads, intended for use with the Juicy 7.
As you mentioned, bending the tab without grabbing the pad material is likely difficult, I will cut the tab a bit short instead.
Odd that nobody has run into this. I see a lot of 06/07 Stumpjumpers out there.
The adapter looks like the standard, typical ISO mount bracket, so you'd think there be more with this problem, and not confined to Specialized, but more specifically Fox Forks. Maybe other riders with the same setup don't pay attention to the details. I have a buddy with Avid Juicy 7's and Fox forks (not sure which model) but I'll look at his setup.
Originally Posted by babetski
You might want to send the photos to Avid, Fox and Specialized, and get their response. From a manufacturing standpoint, perhaps those inner tabs are being bent too much. My Hayes pads have straight grab tabs. In the past, I've written to the likes of Park Tools, Trek/Fisher, Hayes Brake, Manitou Fork and they've all been receptive to my emails. At the least, you'll be alerting them of a problem.
From the first photo, it almost looks like you can shim the caliper away from the axle so the bottom of the brake pad matches the bottom of the rotor wear surface. I wouldn't be surprised if one of the above companies sends you shims to do that.
Good that you are using the Avid pads, I'm a big fan of the factory parts (especially brake components).
each component(hub, fork, brake, brake adapter) plays a role and tolerances for each manufacturer/part is different. in your case all the tolerances put together make it so the pad tab hits the adapter.
Whose adapter are you using? I just looked at mine (BB7 Road caliper w/203 rotor), and there is about 3/16" clearance between the end of the tab and the adapter. I don't remember it hitting when I had a 180mm or 160mm rotor (and associated adapter) on it either. Short of getting a new adapter, just shorten that tab to clear.
On closer inspection of the first picture, I notice the pads are contacting the rotor quite a way inside the outer edge of the braking surface. To my eye, it looks like whoever put this setup together used the wrong adapter!
I would check the rotor for its size, and then go on ebay and find an adapter for that size rotor. I have bought Avid and no-name adapters, and all have worked with no issues. Otherwise, you will have this problem with new pads, AND less than optimal braking power, due to the decreased radius of brake pad contact.
You mentioned using spacers on the adapter--I did this with a 185mm rotor and 180mm adapter, and it worked OK, but I wanted more power, so ended up getting a 203mm rotor and adapter to install. You could try spacers to increase the pad contact radius, or get a new adapter. Your pads should be contacting the continuous portion of the rotor--not down on the arms, like it shows now. The closer you get the pad contact to the outer edge of braking surface (without going off the surface), the greater your power and control will be.
Last edited by badamsjr; 08-08-10 at 10:49 AM.
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