Two Wheel Blogs

Let me start by telling you that there are some goodies in here. I got a lot of this from an online forum, but I added a considerable amount from my own experiences. I am passionate about brake performance, and if you are not also passionate about it, please don't read this. I am very opinionated, and I have developed a lot of frustration over the years dealing with some of these maintenance issues(especially those that involve fixing what someone else did wrong)...I hope what I have learned helps you. I start out with several assumptions (for example, I assume you are using standard cable housing). Some of these tips may not apply to you if you are using special gear...but if you are using special gear, you already know what does not apply to you in here...

Hopefully after you read and understand this, you will have brakes that function in a manner that shows why many prefer mechanical disc brakes over hydraulic.

1) Start with clean or new pads. Clean the rotors with alcohol and never touch with skin.
2) Rotors must be true to within .005" on a dial caliper or damn close to it.
3) You must have avid speed dial levers for this to work. Shimanos with inner adjusters are close but will never do the job as well.
4) Use locktite on all older caliper and rotor mount bolts, preferably blue 242. This product is in your tool kit right? Any self respecting bike mechanic has this stuff laying around…right next to your torque wrench, and lube.
5) Loosen caliper adapter bolts slightly and rotate up in the direction of rotors rotation and tighten. You have your torque wrench and know how to use it right?
6) Loosen caliper mount bolts slightly so caliper can move side to side.
7) Back out red pad adjusters fully.
8) Turn inner pad adjuster in fully then back out 10 indexed clicks. If your brakes are all crapped up and you can not feel the clicks, you need to first clean everything with soap and water and start over.
9) Turn outer pad adjuster in till it bottoms out on rotor. Do not force this step. Rotor should not move in caliper at this time but caliper may move slightly on its adapter.
10) Tighten caliper mount bolts. You are using a torque wrench right? You know the torque specs right? Look them up! How did you get this far with out them?
11) With a cable in your lever and housing run to the caliper (all new or in good shape and at proper length I’ll assume) turn barrel adjuster in full.

You have prepped your cable housings right? This means (at minimum) you have used a grinder, Dremel tool, file or equivalent to prep the ends of the housings so that they are perfectly flat with no burs or irregularities? If you believe that cable prep is not necessary or important, stop reading now…these instructions will not help you. This step is near and dear to me because many “professional” bike mechanics have tried to explain that this step is not needed, and they do not even have tools necessary to perform it. Why bother with disc brakes if you are not going to deal with interface issues with cable housing ends?

12) If your caliper has some miles on it, it might be nice to dab the cable pinch bolt with some wet chain lube, grease, or anti seize.
13) Use a 4th hand tool to take up any slack in the cable and tighten the pinch bolt. As in step 9, do not force this. If you see movement in the actuator arm, go back to step 7.
14) Grab a handful of lever and check for cable slack. There should be none. If this is a new cable/housing install, give it 4 pulls to seat everything into operational position then go back to step 13. Do not reef on the lever, you should never have to use more than one finger on your dialed BB7s. Your cables should not stretch during the life of your brakes…BB7s do not rely on high cable tension to work properly, overly tensioning the cables (reefing on the levers) can actually damage the calipers. If you feel much sponge in the brakes, you probably did not prep the housings! Properly tuned BB7s will provide enough braking force with one finger to lock up and throw you OTB…If you don’t have this much brake force, you should definitely be reading this!
15) Back both pad adjusters out fully.
16) Turn inner pad adjuster in about 4 indexed clicks, pull lever 3 times, spin wheel and check for rub. Repeat this step till any rub is heard. Once rub is heard, back it out 1 click at a time till it goes away then 2 or 3 more for clearance.
17) Repeat step 16 for the outer pad adjuster. With an ear close to the rotor, you should hear zero rub of rotor to pads.
18) Lever throw should suit your style. Too tight? Back out the outer pad adjuster 1 click at a time till feel is reached, not the inner pad.
19) Now that both brakes are set and working, see how 1 lever feels nice n stiff and the other feels like a fresh turd (firm but not solid)? No problems! That’s just a good short front cable vs. that long rear cable and all its housing compression. Rectify this and modulation feel 1/2 turn at a time of the speed dial knob on your levers. Start with the front knob turned in to soften up the leverage ratio of said cable to match the rears feel. A 1/2 turn goes a long way so take your time.
20) See that little hex head on the back of the actuator arm? That’s a preload adjuster for the spring tension on the caliper. Turn it in to suit additional lever feel.
21) I like to trim my cable to about 2" so I can service and re-tune the system several times before replacement is needed. Make damn sure it doesn’t touch or get in the rotor and don’t forget your cable end.
22) Take up slack in pad wear by repeating these steps.
23) Now go ride and dig your new brake feel!

Wondering if your avid pads are old and dead? Measure with a micrometer, pad material and backing plate should read no less than 3.00mm. I replace them at 25% or 3.25mm just to be safe. A new avid pad is about 4.00mm.