Originally Posted by
MoAlpha
Adapters (either way) are about 20 bucks, so the entire question need not concern you.
You can go from CL hub to a 6-bolt rotor, but not from a 6-bolt hub to a CL rotor. The only real downside to this is that those with 6-bolt hubs can't use Shimano's snazziest rotors, which are all CL.