Disc brake rotor diameter 26 in vs 29 in

[02gf74]

I would describe the riding I do as XC; up and down hills so no crazy downhill. On my 26 in bikes I have 160 mm diameter disc brake rotors both front and rear and find that slows and stops my 100 kg (inc riding gear :? ) down adequately.

What effect on braking will using 29 in wheels have? In other words will a 160 mm rotor be less effective on the bigger wheels? My gut feel is that it will be less as the "lever" it is acting on has got longer.

 

[mattr]

It will make a slight difference, but discs tend to be sized for convenience and packaging rather than the size of the wheel/lever. So i doubt you'll actually notice a difference in the real world.

FWIW all our bikes with discs use 180/160. Even the 29ers.

One of the 26ers may well be going 160/140 as the 180/160 gives me more than enough power, and it's a "fun" experiment (yes, i'm a sad middle aged bloke)

 

[Max P]

I'd go 180 up front regardless.

 

[dyna-ti]

Ive been riding a 180/185 front and 160/165mm rear since 1998.
Personally i cannot see any 'balance' with a 160/160, in fact i reckon that a load of made up nonsense :?

Discs came to us directly from motorbikes and those have never had a balance of rotors. Its always a huge one of front and a small one on the rear. It stands to reason that the weight moves forward and so a larger more powerful brake is needed for the front.

 

[mechanical_vandal]

If you have 160mm rotors, they'll be fine but if you are buying new rotors for the 29er wheels then 180s won't be any more expensive so no reason not to really.