New rotor – which end?

All the same size and found a new light one so which end of an XC / trail bike should it go on e.g which end assumes the most wear?

No I don’t have measuring tools, just need a rough idea, I’d assume it’s the front?  Or leave the heavier one on the front for hard braking duty?

My rear wears out twice as fast as the front, but that might just be my riding style causing that, yours may differ?

The one with best performance and least chance of folding up on the front.

My rear wears out twice as fast as the front, but that might just be my riding style causing that, yours may differ?

Same. I assume if I only ever rode stuff well within my comfort zone I’d probably wear them evenly, but when I get scared my back brake takes a hammering 🤣 I’ve never cooked a front brake in the Alps…

Seems sensible.   Its a Quaxar Axis floating rotors, so I’ll put my nearly new on on the front, and the new new one on the back.   I’m moving SRAM centre line to my spare/mud wheels (Silts with Mk1 Forekasters mounted), which seems a better idea for the wet anyway.

Thats a few more grams off the Epic 😀

I would have brakes at both ends, the weight saving of just running one rotor simply isn’t worth the performance pay-off…

If you do go with just the one, some sort of spacer in the unused caliper is a good idea or, for maximum weight savings, remove the whole lever/hose/caliper ensemble as one.

Given your front wheel travels further, always the front, if you only have one performance disc.

I use to think like the OP, then I sheered off a light-weight rotor…

Now I run a larger standard rotor than I think I need, at both ends – not worth the weight saving IME.

I’m not totally against saving weight, my FS while having 203mm rotors front & back does only have a 2-pot calliper on the rear, as 2-pot is more than enough to lock it.