On Thursday, November 16, 2017 at 6:43:23 AM UTC-7, AMuzi wrote:
On 11/16/2017 12:47 AM, Tosspot wrote:
Why do they have holes in them?

Car discs don't, motorbike discs don't, aircraft discs
don't. Why do bicycle discs have them?

Many do have slots or holes. Typical low-end auto discs have
a center air channel. Our researcher discovered this by
completely ignoring normal maintenance:

http://www.yellowjersey.org/photosfr...t/NRCTDISC.JPG

--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971

when there's a brake tug on the front end ...hearing is at aloss with closed windows ...then the brake is inspected with an LED thru slots in the disc...check with Goo Images

I cured one-two with a direct spraying at the car wash..last removing a tick tick not herd thru a closed ac window pass side... accidently pulled into the pressure manure wagon spray hold

when in doubt get down turn wheels spray both sides .. same for bike ? spray first ask later