noise from rear suspension / loud scraping noise

[bmwguy318]

hi everyone

i hope someone can help me out. this thing has been bugging me for months and i cant seem to find out what the problem is, i have a 2015 f80 m3 lower with kw sleeve kit . however the car is only lower about 1" compare to stock ( running 18s te37 255 front / 275 rear tires) and i check everything i have enough clearance therefore it shouldnt be the fender or the wheel scraping on the rear but sometime when i m going down hill or even just on a straight road i will hear this loud metal cutting noise, but not often maybe once or twice a day. the noise is coming from the rear wheel. some said is a backing plate problem with the f80. but i m not sure so i want to see if anyone ever encounter this issue or have a solution for this problem


sorry for the 100+ words post and thank you all for your time have a good one

[RSXDC5]

You probably get rocks caught in your rotor backing plates. That happened to me when I first got this car. Luckily the solution is stupid simple...reach into the rear wheel and push the rotor backing plate in towards the middle of the car, just enough so it bends back a little bit. Do this in a few places on each side and your done!

[TopJimmy]

Sound like you ran over an old metal trash can?

Ha! That's the pebble in the brake backing plate sound. Just plink around with fingertips (don't get cut) and they usually fall out.