What's the reason for a bent back rotor?

**Sammy12** · 21st August 2009, 00:22

Didnt realise till it was pointed out-i have a bent back rotor!
Just wondering what could have caused it?
I've only had the bike a few months, so im only just getting to grips with the "must check before purchases". *duh*!!

**TOTO** · 21st August 2009, 00:38

how about an emergency braking excersise ?

**MSTRS:Me** · 21st August 2009, 09:37

Could be lots of reasons. Most common is overheating, and then cooling down when stopped. The caliper retains heat on that part of the disc, which sets up stresses in the metal, causing warpage.
Could also have suffered a knock or something. Perhaps a hamfisted tyre change.

**quickbuck** · 29th August 2009, 23:36

Originally Posted by MSTRS

. Perhaps a hamfisted tyre change.

Most likely cause...
The back rotor only has about 10% of the energy the front ones get put through them.....

So, my guess is that the wheel has fallen to the floor while it was off the bike.
OR, the rim was stood on while the tyre was levered off...
Or, the rim went flying when it got popped out of the tyre....

Rear disc rotors hardly ever wear out. I'm sure a good second hand one can be found easily....

**MSTRS:Me** · 30th August 2009, 10:41

Originally Posted by quickbuck

Most likely cause...
The back rotor only has about 10% of the energy the front ones get put through them.....

So, my guess is that the wheel has fallen to the floor while it was off the bike.
OR, the rim was stood on while the tyre was levered off...
Or, the rim went flying when it got popped out of the tyre....

Rear disc rotors hardly ever wear out. I'm sure a good second hand one can be found easily....

And they be cheap (compared to fronts)