Huge rotors

[Jx3]

Why do supermoto bikes have such huge rotors?

[Misterkyle]

so they can slow down. Bigger rotors don't get as hot a smaller ones, and because you can break a lot harder on the pavement then you can on dirt, having a bigger rotor is better. 

[Jx3]

Thanks

[shift1313]

and you have less leverage.  when you have a small 270mm rotor on a 21" front you have more leverage.  Think about a breaker bar trying to loosen a bolt.  If you just go to a 17" front but keep the 270mm rotor you are reducing the leverage you have on the tire contact patch.  Just going 310-320mm is okay but the real benefits come when swapping calipers and master cylinders.  Heat is a big factor in fade and warpage.  a dirt rotor will be a few mm thinner than an SM rotor typically.

[Debi]

I agree to all of the above  

 

 I rode a friends bike with a dirt rotor for one session and tried to brake like I normally do and warped his rotor :/ Yep, need Beunos :/

[shift1313]

I agree to all of the above

 

 I rode a friends bike with a dirt rotor for one session and tried to brake like I normally do and warped his rotor :/ Yep, need Beunos :/

 

When i first converted my DRZ i had some OS rotor issues and rode around with my OS dirt rotor for a week.  Even on the street it was pushing it.  I do know guys that race SM with dirt rotors but i dont see how!  Granted my 6 piston caliper and 310 rotor might be overkill for my skill level, id like to have more brake than i can use rather than the other way around:)  There were times I went from my RMZ450 back to my drz for a session and constantly overshot turns cause i just didnt have the same level of brakes.