[1fastvx]

I just got a great deal on an OEM set of Shimano M775 XT Disc Brakes. When I got the order I was very surprised to find that they sent me 203mm rotors front and rear. The only issue is I am wondering if I need to run rotors that big? I have a Reba SL fork in the front that is rated to up to a 210mm rotor, so I am OK there. I ride mostly XC and I can be agressive and I would like to entertain some possible downhill later (Mild). Do I run the 203's front and rear and have mad stopping power or is it just too much brake?

John

 

[dogonfr]

Braking performance and power are personal preference, personally I like a 203 front and 160 rear since most of you stopping power is in the front. If yoyr mainly riding XC a 6" rear should be perfect but a 7" will give a tad extra bite. If you feel you need more rear diameter check into a 7" rotor but a 6 should be more than fine. :thumbsup:

 

[ducktape]

I've got the old M765 XT brakes and I've done some downhill on 6" rotors.
Since you do XC remember also that bigger rotors equals more weight!
I'd go with Dogonfr's suggestion, bigger up front and 160 up back, pretty sure that's a relatively common set up these days too.

 

[Entrenador]

I'm about 195 with my pack and shoes on, and I'm using 160mm front and rear with my 775 brakes on a SC BXC, and they're trouble free. 170mm upfront might be better, but I'm not missing it. How much do you, your gear and your bike weigh? If you go fast and and are heavy, you might keep the 203 up front. Otherwise, I think it's overkill, and if you're going to race, you might consider goin' smaller: they offer a 140mm rear rotor for the XTR(acing) set up.