180 mm rotor on a Carbonda fm909 ?

[endo.alley]

Can I use a 180mm rotor on a Carbonda fm 909? I am trying to do just this with Shimano XT brakes. And a 180mm post mount adapter to space the caliper properly. The mounting bracket of the caliper hits the frame with the 180mm adapter in place. Has anybody had this problem?

[Boybiskit]

I don't have specific experience with the 909, but from your post it looks like the short answer is 'no'...

... but there might be ways around it if it is close to fitting. Some suggestions:
- If it's the caliper that's hitting the frame, try different brakes with a different shape caliper
- If you're running any washers, try removing them. This might just be enough to fit the caliper without hitting the frame
- Try a different adapter. They're not all QUITE the same, so you might find another fits
- Try this if you must, but it shouldn't be recommended:
       - Run a 160mm adapter but space it out with washers until the caliper clears the rotor
       - File down the 180mm adapter until the caliper fits in the frame and hope it still clears the rotor.

This puzzle sounds like an excellent way to graze your knuckles and feel great about fixing a problem / get really frustrated. Your time might be better spent using a good 160mm rotor and setting it up really well.