ASK THE MXPERTS: WHY DON’T MY NEW BRAKES PADS WORK AS WELL AS MY OLD ONES?
After I put brand-new aftermarket brake pads in my CRF450, it stopped worse than it did with the old brake pads. What did I do wrong?
Most likely you made two mistakes:
(1) You need to totally clean the brake rotor. The ultimate way to clean a brake rotor is to use a sand blaster. Besides improving performance, sand-blasting a rotor once or twice a year can actually double its life span. For the average person, 400- to 600-grade sandpaper (a Scotch-Brite pad works in a pinch) is much more accessible and still does a reasonably good job. Use small circular sanding motions, then wash the rotor with soap and water. Some brake cleaners contain chlorides that can leave a contaminating residue.
(2) New brake pads need to be seated. As a rule of thumb, after installing new brake pads (or a new rotor), MXA test riders take the bike out to an open space and slam the brakes on as hard as possible about 10 times. After each stop, we wait about 30 seconds for the brakes to cool and do it again. This is the quickest and easiest way to seat the brake pads to the rotor. Do not try to break in the brakes by dragging them.