On 2018-11-02 09:46, Ned Mantei wrote:
My newer mountain bike uses Shimano Ice-Tech discs (SM-RT81) and JO4C
"metal" brake pads, with DT-Swiss through-axle wheels and XT brakes. In
June I installed a new front disc and brake pads, and neither is
appreciably worn yet.

Even if the wheel turned freely except for some scraping at the very
beginning, later pads and disc would begin to scrape again at one
segment of the disc. Sometimes this seemed to arise from just braking
during a turn. Awhile ago, after a lot of fiddling and multiple tries I
was able to bend the disc a bit to eliminate the noise and have the
wheel turn without binding. But now a very slight binding is back on the
same section of the disc. This isn't noisy, and I might have not even
noticed. However, now when I brake the brakes grab where they bind,
which feels like hitting a little bump at every turn of the wheel.

So some questions:

Can I just ignore the brake grabbing without long-term damage?

Ms. Google suggested bending the disc to avoid scraping. Is there some
other trick? Could it be that my multiple tries at eliminating the
scraping somehow damaged the disc?

Would it be advisable to replace the disc?

Other suggestions?

Thanks for your advice.


Sometimes mine become sightly grabby when too much vegetation has been
"pureed" through there. Then I just keep on riding until that goes away.

Surprisingly the cheapest brake pads (Hangzhou Novich) perform best and
grab the least. In the ads they say ceramic-based. I am not sure whether
that's true but those last 1000mi on the front while the 6x as expensive
ones from the bike shop are gone after 500-600mi and shudder more in a
dirty environment.

Currently running two 8" Shimano ST-66 rotors, Promax Decipher calipers
(not a high end caliper), DOT-4 fluid, Novich pads. Stops on a dime.

--
Regards, Joerg

http://www.analogconsultants.com/