Break rotor and tire change

[85k100RT]

:dunno Hello all,
I've read some great posts on tires and am getting ready to change both due to cracks. Upon close review I picked up a crack in my rear brake rotor.(85K100RT) It goes all the way thru and I need some advice from the wise group here. Should I replace it? Can I? Can I find a used one? Should I care?

Thanks
JF

[jdiaz]

Generally speaking, you probably want to replace it. One crack isn't bad, but a second one might lead to a chunk of the rotor being removed, and upon first application of the brakes might result in an unpleasant experience and/or a ruined brake caliper as well.

Removing the rear brake rotor from a K75/100 is one of the most annoying service procedures on this motorcycle. :D Heat up the tiny allen screws attaching the rotor to the final drive (rear wheel and brake caliper need to come off first) with a heat gun, and then try to remove them. Some genius in the manufacturing department decided that these screws needed to be attached to the final drive with red loctite, even though the rear wheel captivates the brake disc 100% of the time, and it makes these screws difficult to remove. Hopefully you will be able to remove these screws, and renew the disc.

Btw, purchase new screws to attach the new rotor, and remove as much red loctite as possible with a pocketknife. You'll save the next guy a lot of trouble.

[deilenberger]

:dunno Hello all,
I've read some great posts on tires and am getting ready to change both due to cracks. Upon close review I picked up a crack in my rear brake rotor.(85K100RT) It goes all the way thru and I need some advice from the wise group here. Should I replace it? Can I? Can I find a used one? Should I care?

Thanks
JF

Yes
Yes
Yes
Yes

And it is "brakes" not "breaks" - seeing very common misuse - is like chalk screeching on a blackboard - sends shivers up my bake.

Suggest IBMWR marketplace for a used one, or one of the many used parts dealers.

Just a question - is your rear rotor slotted like the front or solid?

FWIW: The slotted ones were on the early '85s and before - and were the subject of a service campaign by BMW (may have actually made it to a recall) for exactly that reason - cracking.