Rotor size for road bike.

hazy_day

Changing my road set-up to a disc brake and was looking for advice on the size of rotors to use 140 or 160. I'm starting out with a set of TRP spyres. Any help appreciated .

ugo.santalucia

The rotor size is dictated by the fork. If it's designed for 160 you cannot use 140, if it's designed for 140 you can use 160 by adding an adapter

hazy_day

Thanks Ugo,I did'nt know that. It's a Cannondale Synapse and in some reviews I see 140 used front and rear and others 160, hence the confusion.It's my first foray into the world of discs(33s and 45s excepted)

ugo.santalucia

hazy day wrote:

Thanks Ugo,I did'nt know that. It's a Cannondale Synapse and in some reviews I see 140 used front and rear and others 160, hence the confusion.It's my first foray into the world of discs(33s and 45s excepted)

Probably best to ask Cannondale.

meanredspider

....but if you have any choice, I'd use 160 up front and 140 at the rear. On firm surfaces like tarmac, the rear can't sustain as much braking due to "weight transfer" so you're more likely to lock the rear unintentionally