Adjusting Mechanical Disc Brakes

Mechanical cable operated disc brakes can work fairly well if you keep them adjusted properly. Below is the procedure I follow to keep mine as tight as possible without dragging. This is mainly for relatively inexpensive cable operated brakes. Some of the higher end mechanical disc brakes like the Avid BB7 are much easier to maintain and work much better. The procedure was developed using the brakes that came on my Mongoose Hitch Fat Tire bike and there was no labeling to indicate a brand name on the brakes.

Bicycle Cable Operated Disc Brake Initial Adjustment

A. Loosen both caliper attachment bolts...the bolts that hold the caliper to the frame.

B. Loosen the adjuster on the inside of the caliper that moves the stationary pad. Usually this is the pad closest to the center of the bike and some calipers have a small retaining screw that must be loosened before the larger adjuster can be turned.

C. Insert a .009" feeler gauge between the disc and stationary pad.

D. Insert a .003" feeler gauge between disc and moving pad...this is usually the outside pad and the one that moves when you pull the
brake lever.

E. Firmly tighten the adjuster on the inside of the caliper that moves the stationary pad.

F. Carefully tighten both caliper attachment bolts that hold the caliper on the frame. When tightening the bolts that hold the caliper to the frame, be very careful not to move the caliper. If you do, the rotor will not be centered correctly in the caliper and your brakes will be applied unevenly and/or drag.

G. Remove both feeler gauges.

H. Check the brakes to ensure they are not dragging and that they are operating properly. If there is a problem that you can not resolve, take the bike to your local bike shop for adjustment.

The thickness of the feeler gauges and the exact procedures followed should be adjusted to fit your specific application. The procedures above are intended to be just helpful hints and may not work for you or your application. Brakes are extremely important and if you are unsure about how to adjust them or are unable to get them working properly, consult a professional.

here is another method for quickly and easily centering your caliper to the rotor to alleviate brake drag.. : loosen the bolts that attach the caliper to the mounting bracket then squeeze the brake lever a couple times to center the caliper to the rotor, then hold the brake lever tightly while re-tightening the caliper bolts securely in the centered position.. spin the wheel to test for any brake drag.. done

efMX....the procedure you posted is what is recommended in my owners manual and it truly does center the disc in the caliper. My sincere thanks for posting the info on how to properly do it.

On my brakes, they seem to work a little better if the gap between the inside pad and the rotor is a little larger than the gap between the outside pad and the rotor. Of course my brake are about the cheapest ones known to man so that might be a factor .

Thought I should post the "Correct" way to adjust brakes...my advice in the first post is what works for me and my cable operated disc brakes but before you try it you should know the accepted way to do things.

For Hydraulic disc brakes...Park Tools has some good instructions: https://www.parktool.com/blog/repair-help/shimano-hydraulic-brake-service-and-adjustment

For cable operated disc brakes...I found this from video by Art's Cyclery: https://www.artscyclery.com/learningcenter/mechanicaldiscbrakesetup.html

Art's also has some pretty good prices on stuff and have been very helpful to me...support them when you can right after your local bike shop .

Note that the uneven fit of some calipers to their mounts and bolts can cause then to shift when tightened, flexing the rotor and negating the technique you have described. The best way to avoid this is to gently snug up the mounting bolts a little bit at a time, switching back and forth between them as you come up to full fastener torque. Even then, it can take a few tries to get the thing tightened without shifting around.

Chalo...excellent point, very true, and good advice on how to avoid the problem.

Your description is exactly what I do...after figuring it out by trial and error, lots of error .

Thank You