Custom Fighters - Custom Streetfighter Motorcycle Forum banner
1 - 6 of 6 Posts

·
Administrator
Joined
·
5,264 Posts
Discussion Starter · #1 ·
Hey, i'm duplicating this with my build thread so feel free to answer in either. I can't see any info on the disc or the packaging identifying if there is a set direction of rotation for this disc shape. There is no counter-sink for bolt / nuts on either side. What do you guys think? ATM i have it going as clockwise with forward motion in the orientation above (hope that makes sense). Googling doesn't seem to be helping me. Being a rear brake i'm not going to lose sleep over it, but thought i should try and get it right. :D
 

·
lɐʇuǝɯᴉɹǝdx&#4
Joined
·
3,518 Posts
My assumption with rotors that have 'spiral' arms between the brake face and rotor bolts is that they should be mounted such that the braking force tries to 'unwind' the spiral. Its the opposite of what 'looks right' at first glance, but when you think about it it makes sense. That way if the metal fails (deforms due to heavy load), at least it doesn't 'potato chip' the brake track by pulling down into rotor bolt, locking up the brake. This may not hold so much for motorcycle brake disks (pretty sure I've seen stock examples that contradict this rule of thumb) but its the rule I learned for bicycle brake disc's, which are thin enough that such failure is a real possibility. Its worth noting that the 'swirly' wheels on my XJ follow this exact rule, if you consider the tire itself as the brake rotor. I'm guessing the metal in those is some soft shit with a low yield strength. :p

So, my guess would be the disk is currently oriented such that your hand would be near the FRONT edge of the dist, with it rotating count-clockwise.
 
G

·
The way you have it in the pic with the arrows etc is right, one way to check is if there is a stamped min thickness or even a makers name that should be away from the wheel although some cheapo discs have no marks at all
 
1 - 6 of 6 Posts
Top