Disc rotor sizes

thedarkangel

Hi all,
Im putting together a marin fs frame for xc riding and was wondering if 180 discs on the back would be much use over 160 (it'll only cost me 2quid extra to upgrade to 180mm)
Its xc and general(trail?) riding Im doing, few long downhills with rocks etc etc
What you do you lot reckon?

Surf-Matt

Depends largely on your weight.

I'm 12 stone so don't need much stopping oomph - any more and I'd look at bigger rotors though.

Extended descents will heat up your rotors but larger ones won't make any difference.

ashleymp777

160mm on the back and 180mm on the front! Thats the best combo for XC riding IMO!

allthegearnoidea

i've upgraded mine to 185 front 165 rear and thay have made a mass of improvement over the old 165/145! allows you to ride a little harder without worrying about stopping!!!

nicklouse

more to do with the brakes.

100kg 160 front and rear. Oros.

SuperCove

I use 185 Front and 165 Rear but alot of it will be depentant on the brand of brake you use and how you like to ride IMO

dav1

what brakes are they and howmuch do you weigh?

I have juicy 5s and weigh 10.5 stone so 160 front and rear is more then enough for me.

schmako

160's for xc, 203's for dh. Seems simple enough as I usually go faster on the dh bike.

stevieboy

185 Fr 160 Rr, was so glad of having the extra power on the front at Margam this weekend and i'm only 10 3/4 st

thedarkangel

Dav1 wrote:

what brakes are they and howmuch do you weigh?

Shimano XT and 11.5 stone

Langers

Having a 180 on the front is great.

nicklouse

thedarkangel wrote:

Dav1 wrote:

what brakes are they and howmuch do you weigh?

Shimano XT and 11.5 stone

you should not need more that 160 for XC use with the XT if they are working.

greasey nipple

180 front, and 140 rear, 140 is way big enough, really easy to lock, thinkin of goin to a 160 on front, reckon 180 is too big really.

Planet_x111

I've just put a 203mm on the front but still have a 165 on the back. It'll be a 185mm soon though. Yes I do need the extra power as I'm 'big-boned' (255lbs). It's a XC bike and not a DH jobby.

stu8975

Im about to change the front to a 185mm on my mono minis,rear is 160mm, under normal conditions they would be fine for the most part, but im an aggresive rider and weigh approx 13stone, but i wouldnt go any bigger for xc use.

icedmind

160 front and rear
im 130lbs and its good enough to stop me whatever up or down hill
i think what rotor (make,material), pads and what brakes makes a difference as well
i found hope rotor is the best i have tried so far

toslow

Depends on where you ride and how you ride . 160 front and rear has always been enough for me . here in cornwall i've found some great dh bits but never felt the need to upgrade . Or may it's cause i'm a wimp and never attack down hill at full tilt . my normal excuse is i'ts because i ride a stumpy ht and it's not built for such things.