Originally Posted by
Mr IGH
I run 160 front and rear but if I was going to add a 180mm I'd use it on the rear brake. Long descents need heat dissipation but if conditions are sketchy dragging the brake can cause sudden lockup, much better to lock up the rear wheel than the front....
Almost everyone running a bigger rotor does it up front, where most of the braking takes place. Mechanical disc brakes have great modulation. YRMV