I’m about to order some new rotors and I’m dithering between 160mm and 180mm, the pertinent details are: I’m 65kg with gear on, my bike is a 140mm full sus weighing 11kg, and I have Formula R1 brakes working well. I currently have 160mm rotors which stop me perfectly well, but I’ve only been riding XC where there is little call for repeated braking so fade doesn’t come into play, and I’m going to be getting into some more brake taxing riding. The new rotors will be floating to try and help dissipate the heat. So what would STW suggest is the rotor size for me?
Cheers

I’d stick a 160 on the back and a 180 ont front

+1 to that.

180 is really all you’ll ever need on the front, unless you’re vast

If you’re happy with 160f+r why not stick with it? I use 180f/160r at 80kg without gear etc and have never had a problem with brake fade on +300m vertical descents – and that’s without floaty rotors.

if your fork can take it put a 203mm on there. rear max what the frame will take.

I put 200F/180R on my Hardtail.

However, I’m 100KG, and can’t see any disadvantages with ‘going big’

If you’re going light probably stick to 160 f&r, if weight is less of an issue 180/160 is a good shout, weight no object 200/180. You’re pretty light so 160 may be fine unless you’re dragging the brakes down big hills. I’m about 20Kg heavier than you togged up and use 160 f&r on my xc bike, fine for JRA, wouldn’t want to take it down scary fast/steep stuff tho.

I’m in the camp of bigger rotors, even for trail bikes. I’d rather be over braked than under braked.

180/160

203/180 here, but then 160/140 on my weight weenie bike and they’ve been fine too.

For actual riding I don’t see any real downside to being overbraked. The weight penalty is paltry.

I’ve just put some 203/180mm Formula 2-piece rotors on my bike. Was running Hayes and Hope (same size) before but wanted to save a bit of weight. They have made a huge difference to the braking power and control. Weights are 137g front, 117g rear so saved nearly 100g’s.
£32 each from alltricks in France..

Thanks for the thoughts peoples, seems 180 front 160 rear is the way to go, cheers.