Brake Rotor Size Advice

[Muzza]

Quick question to all, having just put new 4 pot XT brakes on my Levo,(front & rear). I read that alot of riders have 4 pot on the front & 2 pot on the rear to even out the braking as the front does the majority of the stopping?
I'm wondering if I should go for the Shimano Ice Tech Rotors with a 180 mm rear & 203 mm front rotor to counter. Or perhaps have 203 mm both front & rear?
Any advice would be appreciated.

 

[slippery pete]

There is some degree to which it depends on the type of riding you do. The idea that the front brakes do all the stopping is incorrect for steep technical riding for instance.

I run all my bikes on 200/200 at the moment because there are situations I take them into where a 180 rear just isn't enough.

Balancing the brakes through rotor size isn't needed. Your brain is better at working this stuff out than you give it credit.

 

[Flatslide]

Yeah, 203 both ends and squeeze the rear less hard. More braking leverage is nice on the downhills, especially with a weighty bike

 

[Mteam]

On my orbea I have shimano xt 4 pots with 203mm rotors front and back and it feels fine.

But on my other bike with sram code rsc brakes I have 203 on the front and 180 on the back. I did try it with 203 on the back but it felt too grabby, too easy to lock up on loose surfaces, so went with 180 on the back.

The sram codes are more powerful than the xt's though so maybe that explains why I prefer a smaller rear disc with the codes?

 

[Muzza]

There is some degree to which it depends on the type of riding you do. The idea that the front brakes do all the stopping is incorrect for steep technical riding for instance.

I run all my bikes on 200/200 at the moment because there are situations I take them into where a 180 rear just isn't enough.

Balancing the brakes through rotor size isn't needed. Your brain is better at working this stuff out than you give it credit.

Thanks, I think you are right on the money, as my riding advances into the more technical steeper downhills I may regret the 180 on the back so easier to just play it safe & keep to 203.

 

[deksawyer]

I have a 223 front and a 180 rear. Works very well for me. Both Magura 2 pots as well.

I was gonna put the 203 I removed from the front on the rear, but the rear was so good, I didn't see the point of fitting a bigger rotor.

 

[Dirk74]

Beside the personal preference it also depends on what is the largest size that the manufacturer approved for the bike.
Going larger than that could lead to something break at riding resulting in bad injury. Losing Warranty as well.

 

[Shane(NZ)]

Hope 225mm on front 203mm on rear XT 4 pots
25kg bike 115kg rider , works pretty good.

 

[Muzza]

Good points Dirk74, original rotors were 200mm so not much difference other than manufacturer brand.

 

[R120]

I wouldn't go 180 on the rear, the weight of an emtb means it starts cooking early if riding hard - I run 220 up front and 200 out back. Interesting article here on rotor sizes, you can see some of the DH World Cup riders are going 220 rear and 200 front now too in some of the recent bike checks on Pinkbike and the like. Myriam Nicole being one example

Bike Check: Myriam Nicole's Commencal Supreme Mullet - Pinkbike

Myriam's decision to go the mixed-wheel route paid off at French National Championships.

www.pinkbike.com

Interesting article on rotor sizes here:

Ending the rotor size myth – Why you should have a bigger brake rotor at the back than the front

Small up front, big at the rear? Contrary to popular belief, many of us should ride with bigger rotors at the rear than at the front. Read on to find out why:

enduro-mtb.com

 

[Muzza]

I wouldn't go 180 on the rear, the weight of an emtb means it starts cooking early if riding hard - I run 220 up front and 200 out back. Interesting article here on rotor sizes, you can see some of the DH World Cup riders are going 220 rear and 200 front now too in some of the recent bike checks on Pinkbike and the like. Myriam Nicole being one example

Bike Check: Myriam Nicole's Commencal Supreme Mullet - Pinkbike

Myriam's decision to go the mixed-wheel route paid off at French National Championships.

www.pinkbike.com

Interesting article on rotor sizes here:

Ending the rotor size myth – Why you should have a bigger brake rotor at the back than the front

Small up front, big at the rear? Contrary to popular belief, many of us should ride with bigger rotors at the rear than at the front. Read on to find out why:

enduro-mtb.com

Thanks heaps, will now look around to see if I can source a 220 rotor for the front. Don't think Shimano do them but maybe Hope?

 

[urastus]

Yeah, and it is kind of a fallacy re the front having the most stopping power - that's dependant on the surface. I use my rear brake much more because often I'm in loose stuff, slow manoeuvring, or trying not to hinder the front rolling over something or when I'm near the bottom of a steep rock slab etc. I always have to replace rear pads first. Now, if I was riding on the road - totally different.

 

[Al Boneta]

Thanks heaps, will now look around to see if I can source a 220 rotor for the front. Don't think Shimano do them but maybe Hope?

Hope rotors will likely rub against the inside of the brake adapter and caliper. Galfer makes a 223 that I just tried out and the braking doesn’t seem any better than a 203 Icetech rotors

 

[Muzza]

Hope rotors will likely rub against the inside of the brake adapter and caliper. Galfer makes a 223 that I just tried out and the braking doesn’t seem any better than a 203 Icetech rotors

Cheers again, great to get advice from members that have experience with different rotor sizes. Now think I will just play it safe & get Ice Tech 203 front & rear. Plus down here in NZ our options are pretty limited.

 

[Muzza]

Yeah, and it is kind of a fallacy re the front having the most stopping power - that's dependant on the surface. I use my rear brake much more because often I'm in loose stuff, slow manoeuvring, or trying not to hinder the front rolling over something or when I'm near the bottom of a steep rock slab etc. I always have to replace rear pads first. Now, if I was riding on the road - totally different.

Thanks for the great advice, slow technical is where I'm heading & I believe I will also be relying just as much on the back brake?

 

[urastus]

Thanks for the great advice, slow technical is where I'm heading & I believe I will also be relying just as much on the back brake?

I'd say more. It's a common technique to drag the back brake while keeping the power on while doing slow manoeuvring. It gives you a lot more control. Consider a track stand, which is extreme and generally both brakes; that sort of control in technical stuff. Even riding skinnies - drag the rear brake a bit to help keep you straight.

 

[Philly G]

I wouldn't go 180 on the rear, the weight of an emtb means it starts cooking early if riding hard - I run 220 up front and 200 out back. Interesting article here on rotor sizes, you can see some of the DH World Cup riders are going 220 rear and 200 front now too in some of the recent bike checks on Pinkbike and the like. Myriam Nicole being one example

Bike Check: Myriam Nicole's Commencal Supreme Mullet - Pinkbike

Myriam's decision to go the mixed-wheel route paid off at French National Championships.

www.pinkbike.com

Interesting article on rotor sizes here:

Ending the rotor size myth – Why you should have a bigger brake rotor at the back than the front

Small up front, big at the rear? Contrary to popular belief, many of us should ride with bigger rotors at the rear than at the front. Read on to find out why:

enduro-mtb.com

Thanks R120 for the links, super interesting ?

 

[R120]

I would add in that a lot of its to do with individual technique too, there's no best solution for everyone - I for example use the front brake for stopping, and the rear brake for adjusting the attitude of the bike so to speak, which is a habit kinda ingrained in me from years of riding road motorbikes, along of course with where and how you ride.

 

[Shjay]

I am running Magura MT5s with 220 MDR-P rotor on front & 200mm MDR-P rotor on the rear, great setup

 

[flash]

Very happy with my XT brakes and 203mm hope rotors front and rear. 23kg bike and 96kg rider and it brings me to a rapid halt when I need and I never fear running out of brake. If I were a more downhill orientated person I'd probably go for 220's front and rear. I'd rather be a bit over braked than underbraked.

Gordon

 

[Muzza]

I am running Magura MT5s with 220 MDR-P rotor on front & 200mm MDR-P rotor on the rear, great setup

Nice set up mate, Magura offer a bit of color choice as well I believe?

 

[Shjay]

Nice set up mate, Magura offer a bit of color choice as well I believe?

They are a bit bling upgraded to Loic Bruni levers on the MT5s too

 

[urastus]

I’d like to say that I talked to some German mtb testing engineers and they said trickstuff breaks on 180 rotors break better-all-around than 220/200 for every other brand. Only 16 more month wait for my breaks.

—I’m in Stuttgart, where the SL motor is made.

I would be surprised if they said anything else - they're promoting their product. Now, if it was tested and the results shown...

 

[Cavi]

I have 4 pots on front and rear, and currently 200 front and rear, but I just ordered a 220 for the front, I weigh 220kg and went on a long descent this past weekend and definitely felt that I was loosing some power twords the end, I was worried I was boiling

 

[All4Fun]

Nice set up mate, Magura offer a bit of color choice as well I believe?

Same components here, only difference that i run the 200 at the front and the 220 at the back on my Flyon.
Organic front pads and metal rear.
I've used this in the mountains of France and i like this setup, enough stopping power and speed control at long 25% and more desents.

And yes colored rings too...

De groet'n...

 

[04fuxake]

I'd say more. It's a common technique to drag the back brake while keeping the power on while doing slow manoeuvring. It gives you a lot more control. Consider a track stand, which is extreme and generally both brakes; that sort of control in technical stuff. Even riding skinnies - drag the rear brake a bit to help keep you straight.

Dragging the back brake totally transformed my uphill switchback riding.

 

[jbrown15]

I upgraded the brakes on my bike from Sram Guide RE's with a 220mm front and 200mm rear to Shimano XTR with front and rear 203mm Ice rotors. I'm much happier with the XTR's, better modulation and the rotors run much cooler than the steel SRAM rotors. Which I completely cooked in two riders, mean while the Shimano Ice rotors are still going strong.

I'm going to change out my hubs soon and go with something that offers a center lock setup and then I'll switch out to Shimano Freeza rotors which run even cooler than my Ice rotors. For me I'd rather have a 203mm rotor that runs cooler than any other 220mm rotor that gets cooking hot causing the brakes to fade due to heat.

 

[urastus]

I upgraded the brakes on my bike from Sram Guide RE's with a 220mm front and 200mm rear to Shimano XTR with front and rear 203mm Ice rotors. I'm much happier with the XTR's, better modulation and the rotors run much cooler than the steel SRAM rotors. Which I completely cooked in two riders, mean while the Shimano Ice rotors are still going strong.

I'm going to change out my hubs soon and go with something that offers a center lock setup and then I'll switch out to Shimano Freeza rotors which run even cooler than my Ice rotors. For me I'd rather have a 203mm rotor that runs cooler than any other 220mm rotor that gets cooking hot causing the brakes to fade due to heat.

For sure, but I think bigger rotors run cooler than smaller ones.

 

[jbrown15]

For sure, but I think bigger rotors run cooler than smaller ones.

For sure they will as there more surface area on a larger rotor, but a 203mm Shimano Freeza rotor is going to run cooler than any 220mm standard steel rotor.

 

[schleprx7]

I upgraded the brakes on my bike from Sram Guide RE's with a 220mm front and 200mm rear to Shimano XTR with front and rear 203mm Ice rotors. I'm much happier with the XTR's, better modulation and the rotors run much cooler than the steel SRAM rotors. Which I completely cooked in two riders, mean while the Shimano Ice rotors are still going strong.

I'm going to change out my hubs soon and go with something that offers a center lock setup and then I'll switch out to Shimano Freeza rotors which run even cooler than my Ice rotors. For me I'd rather have a 203mm rotor that runs cooler than any other 220mm rotor that gets cooking hot causing the brakes to fade due to heat.

Good luck finding rotors larger that 180mm with Centerlocks. I ran into issues finding 200mm or 203mm rotors that I run on my non-ebike when I bought some new wheels a couple of months back. Ended up using adaptors so I could use 6-bolt rotors on my centerlock hubs.

In regards to using Hope 220 rotors, you should have no issues with clearance on the forks. I've used these with Fox 36, Rockshox Lyrik and Marzocchi Z1s. Your more likely to run into clearance issues with the rear brakes, where the post mounts on the frame and any adapters can interfere with the large rivet? that Hope uses to secure the brake surface to the aluminum carrier.