How to dial-in Avid BB5 mechanical disc brakes
October 30th, 2006 by Tim GrahlThe Avid BB5 mechanical disc brakes have just one pad adjustment knob as opposed to the Avid BB7 which allow you to adjust both pads.
This how-to is for the Avid BB5 and is the easiest, most consistent way I’ve found to dial-in these brakes.
Tools you’ll need:
- 5mm Hex wrench
- spare paper or biz card
- P-Handled T25 Torx Wrench
Optional:
And the steps…
- Use the 5mm hex wrench to loosen the bolts that connect the brake to the frame. Don’t pull the bolts completely out, however make sure there is enough space so you can move the caliper easily.
- Put a spacer between the rotor and fixed brake pad. This is the pad that’s farthest away from the wheel.
In the picture I used a few sheets of thin paper. A buddy of mine has used a business card as well. Basically you just need something that will provide a small amount of space between the rotor and stationary brake pad.
- Tighten down the pad adjustment knob by turning it clockwise. You can do this by hand, however it’s easier to use the P-handled T25 torx wrench. Make sure you tighten the knob all the way down. Don’t overtighten and break anything, however make sure it’s really snug.
- Tighten the bolts that attach the brake to the frame using the 5mm hex wrench.
- Loosen the pad adjustment knob all the way and carefully remove the paper spacer.
- Tighten the pad adjustment knob until you have optimal stopping power. Be sure to test it out by spinning the wheel by hand and pulling the brake before you try to ride again.
So what did we do?
One of the hardest things about installing the Avid BB5 caliper on the frame is making sure it is in line with the rotor and that there is the right amount of space between the rotor and stationary brake pad. Adding the paper spacer ensures there is good clearance between the rotor and brake pad. By tightening the pad adjustment knob all the way down with the caliper bolts loosed you are making sure the pad and rotor are lined up correctly.
Have any questions or thoughts? Leave them in the comments.
What is RSS?
Get our articles in your inbox:
Hello,
It looks like you didn´t install the CPS washers between the calipers and the brackets. This is critical as it is the CPS hardware which allows the caliper to be properly aligned with the rotor. Not having the CPS washers installed also causes the caliper to bite to low on the rotor which may lead to decreased brake performance.
You can find the instructions for proper installation/tuning in the following document:
http://www.sram.com/_media/techdocs/2006_BB5and7_English.pdf
Regards,
Pablo.
Thanx!
This bit of info. was truly helpful. I’m running smooth again.
Brilliant! Worked like nothing else had, thanks so much. Now if I can just figure out if the warp in my rotors is enough to warrant replacing them.
I used a folded 3×5 card, nice because you can tear it into a longer strip which makes it easier to get between the pad and rotor. Who needs them BB7s?
Thanks a lot Tim! They were mis-aligned and squelling, after going thru the owner’s manual intructions and yours, I decided yours made more sense and to try it first. It worked! It now has a smooth clean accurate feel without drag. I used a plastic card slightly thinner than a CC, it was a bit difficult inserting in the rear caliper though, may try something thinner next time.
Thought I’d include the owner’s manual instructions for camparison…
Align The Caliper
A. Use your fingers or a Torx® wrench to turn the inboard pad adjustment knob
clockwise until the rotor is centered in the caliper. This positions the pads for
the next step in the installation.
B. Make sure the CPS bolts are loose enough for the caliper to move freely.
C. Squeeze the brake lever to compress the brake pads firmly on the rotor.
D. While still holding the brake lever, tighten the CPS bolts. Once they are tight you can let go of the lever.
Adjust The Pads
Back the adjustment knob off (counterclockwise) until the rotor spins freely.
Now you can dial the pad in or out until you find the brake action you prefer
(make sure, of course, that there’s no drag on the rotor). If you can’t seem to
get the feel you like, or the rotor is dragging, repeat step 5.
Wow, that worked better than expected. I was using the rear too much, and it finally retaliated after a drenched, sandy trip at Chilhowee system in TN. Thanks so much for the quick fix, had no problems whatsoever and I’m stopping on a dime again!
One thing I noticed from the SRAM instructions compared to yours is that SRAM says several times to make sure the torque arm(I assume they are speaking of the break actuator arm the brake cable is connected to) is all the way out until you need to adjust it for pad wear. From your pic’s I see the the torque arm is not all the way out. I found that I could not ge enough adjustment in the brake until I moved the torque arm close to the barrel adjuster and then tightened the brake cable. That is also what it looks like in your pic. Any comments?
Don’t leave the “torque arm” all the way out. the brakes will feel spongy. I choke up on mine quite a bit.
Basically, at the point of maximum braking, you want the cable to be pulling relatively straight. the way it’s set up in the pictures is pretty much perfect.
I’ve dealt more with the Bb7s, which IMO are a better brake only because the throw of the caliper arm is what makes it feel like crap, or what makes it feel as good as hydraulic brakes. Being able to adjust the throw and the pad positions independently, you can dial them in to feeling as good or better than much more expensive brakes.
Great tip! Worked flawlessly. Saved me a trip to the bike shop to perfectly dial in teh brakes. Thanks.
Excellent!!!
I have an 08 RockHopper with BB5’s and I had NEVER been satisfied with the front brake’s performance (never stopped well, heading down a hill, gripping the brake lever full force would still only bring me to a stop slowly and really squeaked). Of course, the rear just skids if I’m not careful.
I’ve had it into the shop several times with the tech telling me there was nothing wrong he could see (but he never actually rode it to try).
Your above instructions took me (a bike beginner) less than five minutes, armed only with a 5mm Allen wrench and a sacrificial business card. This bike stops flawlessly now. I almost went over the bars the first time–it’s going to take some getting used to.
Thanks!
Fantastic! I had my mechanical breaks stollen. Just replaced these with Avid BB5’s, and they were not fitted well at the store. They’ve been making a lot of noise.
I’ve never done this type of fix before. Just applied the changes you described - took less than 5 minutes, and the bike is now very smooth - like new - and the breaks are strong.
Good tips and clearly described.
Cheers,
Adi (London, England)
This was a big help. Thanks for the super easy fix. It really suck when the bike shop can’t even do something that easy.
Thanks again
Attention BB5 folks - you can pop off the red cap on the outboard “non-adjustable” pad side of the caliper. This exposes a nut head. This is actually the pad adjuster for the “non-adjustable” pad! I got my trusty dremel out, slapped a thin cutting wheel [wear eye protection pleez], and cut a flat head screwdriver sized notch in the bolt head.
This mod turns your BB5 into a fully functional BB7 brake - albeit, the pads are still round, not square like the 7’s…..and you also have the benefit of yet another barrel adjuster on the caliper for more cable slack tuning options……
I did this mod years ago for my singlespeed, and it works superbly - no need to up-spend for BB7’s if you do this mod.
I found these instructions really easy to follow. Thanks heaps for posting them in this way.
Thanks so much for the tips and the clear pictures. The squeaking in my brakes was driving me crazy and a mechanic said they were just going to be that way. With 3 business cards on the fixed side of the front brake and one business card on the fixed side and one on the adjustable side for the back brake they are now both working with full stopping power and no squeak. My ears thank you!