What keeps the disc carriers from rotating on the wheel hub? Does the clamping force from the bolts create enough friction (carrier to hub) to hold them firmly in place AND/OR do we rely on the bolts themselves to stop the carrier from rotating? Or maybe both?
I'm not sure, but I think both.
I agree with Howie. I'm certain there are engineering documents somewhere...
but it's kinda common sense.
I'm thinking that they'd move a tiny bit if there was no/too little friction - moving within the gap between bolts and holes.
Quote from: stopintime on December 01, 2025, 01:12:13 AMI'm thinking that they'd move a tiny bit if there was no/too little friction - moving within the gap between bolts and holes.
The tolerance is pretty small between the bolts and the holes. If they move, they'd only move once as the forces are always in the same direction because bikes don't have reverse.
So we should rotate them hard while fastening the bolts? 😎
Quote from: stopintime on December 01, 2025, 04:57:35 AMSo we should rotate them hard while fastening the bolts? 😎
My spatial relationships are being stressed. ;D
I can hold them while you rotate/spin...
Some Japanese bikes use a shouldered bolt with a larger diameter than the threads. The wheels have a corresponding hole to receive the shoulder thereby providing a separation of the braking forces versus the clamping forces.
I liked that. I wished Ducati had done that. But yeah, they hadn't by that evolutionary point, so the rest of the above makes sense.
Also, it was scary to occasionally see someone use a stainless bolt for rotor attachment. Anywho.
Thanks all 👍
What material is the matte black torx ones?
IIRC, hardened steel.
Older bolts were 8.8 grade. When replacing them, I always used that grade or higher.
I ordered a box of 12.9's one time b/c I liked the finish better.
12.9s are in good supply from my local bolt specialist. For some reason 8.8s aren't available in some sizes any more. The gold colour of the oem 8.8 of the nineties is hard to find here.The 12.9s are so bright they look like highly polished stainless.