Hello

Don’t no if to drop down to 140 rotor on the rear of my 29er silly or not?ii understand smaller rotors will get hotter over
Longer periods.mainly riding cross country no super g-narage.

Thanks

L

My question would be why? Unless you’re trying to win some epeen contest on weight weenies you’ll be reducing braking performance just to save a few grams. I wouldn’t say it was silly (provided you need to buy a new rotor anyway) just pointless

Wheel size is pretty irrelevent.

Just put one on.

Wot FuzzyW said, I still scratch my head every time I (re)notice the 140mm disc on my g/f’s bike… Why, just why did anyone think there was a need to go smaller than 160mm? By all means try it, it’s you choice, but it seems totally pointless to me. Must remember to change her’s at some point

I’m on 2×160, but don’t run bigger than you need so give it a try if you are replacing anyway.

I saw a vid of a pro Enduro rider who said they sometimes run smaller rotors on the back to get better feel. It’s not about power it’s about control.

I run 140 rear rotors, have done for years, it’s what my last few bikes came with, it’s lighter, it stops me, why change?

As above, wheel size is irrelevant.

140 rears and plenty of power on the back. No problem for XC racing and trail centre descents.

I had 140 on the back before, they get VERY hot.

On the plus side they never seem to wear out pads as they’r always hot!

Wheel size does make a difference, energy (dissipated through braking)= force(of the brake pad)*distance (traveled by the rotors brake track through the pads), so the slower rotating 29er wheel (same speed at the circumfrance gives a slower rotation as the diameter’s bigger) needs more force (brake pad friction) for the same size rotor. I ran 140/160 on my 26er and 160/180 on the 29er and they feel comparable.

Wot FuzzyW said, I still scratch my head every time I (re)notice the 140mm disc on my g/f’s bike… Why, just why did anyone think there was a need to go smaller than 160mm? By all means try it, it’s you choice, but it seems totally pointless to me. Must remember to change her’s at some point

Why? If they work leave them. As Fuzzy said, no point spending moeny if they work (presumably they do, as it’s you nocticeing them visualy rather than her whilst riding it).

180 front / 140 rear on both our bikes, no problems, easy to lock the back wheel so thats enough power…

When you’ve a bunch of 160mm disc’s (all upgrade to 180’s on mine & friends bikes) & adapters sitting round, there no cost involved. I see it in the garage, she not ridden much this last year due to the weather, so I’ve no idea what it the performance is like, just seems like a stupid idea… but as I say “By all means try it, it’s you choice, but it seems totally pointless to me“.

It is so easy to lock up a rear disc brake I’d question why you’d want to go bigger than 140?