Avid BB7 Problem

[pirate]

So, I got my new wheels back from the shop, got my tires all mounted up, and went to put them on my bike... Well, the front one is fine and all, but my back rotor is now rubbing on the inside of the caliper of my BB7s. I tried turning the red knob as far counter clockwise as it would go, but the rotor is still just barely rubbing. It looks like the whole brake unit needs to be moved just a little toward the wheel. Is that possible? I have ZERO clue when it comes to disk brakes, so please forgive my ignorance.

[jabberwocky]

The Avids are post mount. Loosen the bolts holding the caliper to the adapter and it can be realigned easily. I usually try to recenter the pads in the caliper using the red knobs (leaving a little bit of space between the pad and rotor), then squeeze the lever and retighten.

No worries, its quite easy to do. Post up if you have any questions and I can take a picture or something to help explain.

[joep]

1) Loosen the two bolts holding the caliper to the adapter
2) Tighten both red knobs so that the wheel can't spin, and the rotor is in the middle of the slot.
3) Tighten the two bolts that you loosened in step 1.
4) Loosen both red knobs by a couple of clicks.
5) Spin the wheel and check for rub. Back off pads as necessary.

I adjust mine so that the inner pad is as close to the rotor as possible and the outer pad is far enough away to give the right "feel" when braking.

[eloach]

What JoeP said always works... unless -

1 - The wheel is mis-mounted
2 - The rotor is bent.

You may laugh at #2, but I actually had a guy put a rotor on my bike AFTER I saw him drop it 5 feet onto a concrete floor where it hit on edge but not vertical. As soon as he handed me the bike I spun the wheel and checked the rotor, then handed the bike right back and told him to replace the rotor.

To check the rotor:
1 - Put a light on the back side (flashlight or other)
2 - Adjust as per JoeP until just the "right" clearance shows on both sides of the rotor
3 - Spin the wheel and look for waver in the rotor.
If there is more than a 1/32 to 1/16 waver the rotor is out of true.

I have also seen bent rotors from improper tightening of the screws that hold the six bolt type (although you really have to ape it to do that) and was shown one that was bad right out of the box at a bike repair clinic.

[pirate]

Cool! Thanks a lot for the help, everyone. :)

[pirate]

Man, you guys are geniuses... JoeP's method worked like a champ, and only took like 2 minutes! Thanks again.

Brian

[punga]

On the subject of bent rotors: they can be straightened (or at least bent back enough that so they don't rub). Shops have tools made for it, but you can use 1 or 2 crescent wrenches. Watch from above through the slot in the caliper as you spin the wheel, sorta like truing, except you're bending the rotor back and forth. Just go easy and don't try to fix it with one bend. Push/pull a little, spin and check, push/pull a little more.

punga!

[pepelkod]

Don't touch the rotor with your greasy paws.

If you do touch it, wipe it with brake cleaner, rubbing alcohol or bleach.

If you get oil on the pads you will loose stopping power.

The solution after that is either replace the pads (recommended) or take the cheap route like I did and cook them on your outdoor grill.

-D