chucknovice
Registered
Some time back, I replaced my K1's front discs because I was getting annoying pulsing on the brake lever. The discs had reached their service limit, one disc was dished like a dinner plate somehow, and the other had 0.3mm runout.
After a while I noticed that I still had low-speed brake pulsing, so I checked the runout again. The left was fine (0.05), but the right was 0.2mm. I sprayed the little disc bobbins with brake cleaner and rotated them but it hardly made a difference. But then I checked the inner disc, and it also had runout. So I tried shimming the hub with adhesive copper tape (the stuff for keeping snails out of plant pots). I over-compensated at first, and probably re-fitted the disc and wheel at least five times, but I eventually got the runout down to 0.05mm with just two small pieces of tape (the tape is around 1-2 thou of an inch, or about 0.03mm in the new money)
Now, there is no more pulsing, and the brakes feel fantastic (probably also from cleaning off all the brake dust and dirt).
Still, after going through two discs with the same issue, I find it strange that it points to the wheel hub itself possibly being poorly machined at manufacture??
After a while I noticed that I still had low-speed brake pulsing, so I checked the runout again. The left was fine (0.05), but the right was 0.2mm. I sprayed the little disc bobbins with brake cleaner and rotated them but it hardly made a difference. But then I checked the inner disc, and it also had runout. So I tried shimming the hub with adhesive copper tape (the stuff for keeping snails out of plant pots). I over-compensated at first, and probably re-fitted the disc and wheel at least five times, but I eventually got the runout down to 0.05mm with just two small pieces of tape (the tape is around 1-2 thou of an inch, or about 0.03mm in the new money)
Now, there is no more pulsing, and the brakes feel fantastic (probably also from cleaning off all the brake dust and dirt).
Still, after going through two discs with the same issue, I find it strange that it points to the wheel hub itself possibly being poorly machined at manufacture??
