What Size Rotor For A Mod On Back

[Skilled trials]

hey guys im ordering a new brake and not sure what rotor size would be best. Its a bb7 and i like the idea of 203mm but would it be tooo big for a mod back wheel. Otherwise 185mm? Thanks

[Mark W]

203mm would definitely be too big! 185mm at the most I'd say, most people seem to deal with a 160mm on the back well enough

[LukasMcNeal]

I would say 180-185mm really thats pretty much the smallest you should go if its a mechanical brake.

[Skoze]

I would say 180-185mm really thats pretty much the smallest you should go if its a mechanical brake.

Have you ever used a BB7...?

160mm will be fine, but get a 185mm if you want some megapower. 203 would just be mental!

[Alex Dark]

160 will be fine...if you're any of the following you may warrant a 180: a) fat horrendous at setting up brakes

[LukasMcNeal]

Have you ever used a BB7...?

160mm will be fine, but get a 185mm if you want some megapower. 203 would just be mental!

I have a front 160mm, I would just feel that I would get a 180mm to be sure.

[rupintart]

I'm curious as to why you WOULDN'T want a 203 on the rear? When the brakes are the most important thing, especially the rear, why not?

180's are all you really need on the front of a stock, yet people still run 203....

All the mods I've ridden have been maggies on the rear...curious is all.

Edited January 29, 2010 by rupintart

[MiuSliS]

I'm curious as to why you WOULDN'T want a 203 on the rear? When the brakes are the most important thing, especially the rear, why not?

180's are all you really need on the front of a stock, yet people still run 203....

All the mods I've ridden have been maggies on the rear...curious is all.

Because, bigger rotor means bigger chance that you'll bend it.

Edited January 29, 2010 by MiuSliS

[Ben John-Hynes]

biggerSmaller rotor means bigger chance that you'll bend it. your back when you fall off the rear.

[Mission Prodigy Trials.]

You should definaty put a 160mm Rotor on the rear and 180mm on the front like me.

[Dale-Hill]

Have you ever used a BB7...?

160mm will be fine, but get a 185mm if you want some megapower. 203 would just be mental!

When I had dual bb7 i found 160 to not bite and hold well enough, got a185 then and it was amazing

[Mark W]

I'm curious as to why you WOULDN'T want a 203 on the rear? When the brakes are the most important thing, especially the rear, why not?

Because it's a shitload easier to hit, plus with smaller wheels you need a proportionally smaller brake for the same power. I can't remember what it'd be exactly, but a 203mm on a mod would be about a 225mm on a stock, or there or thereabouts. Bearing in mind mods are smaller and lighter than stocks you also need less stopping power in general, so something like a 160 or 180 would be fine. I run a 160 on mine because I find that it gives me plenty of power and hold, but you can still modulate it nicely which is useful for riding natural stuff.

[Dale-Hill]

Because it's a shitload easier to hit, plus with smaller wheels you need a proportionally smaller brake for the same power. I can't remember what it'd be exactly, but a 203mm on a mod would be about a 225mm on a stock, or there or thereabouts. Bearing in mind mods are smaller and lighter than stocks you also need less stopping power in general, so something like a 160 or 180 would be fine. I run a 160 on mine because I find that it gives me plenty of power and hold, but you can still modulate it nicely which is useful for riding natural stuff.

You don't use a bb7 though do you Mark?

I feel you need at least 180+ on a mod rear for bb7

[Mark W]

Nah, was just replying to Rupintart's question in general.

[rupintart]

I know concerning the whole leverage thing with stock vs mod wheel size, but why would anybody say it's too much brake? I would rather have too much power in the rear rather than "just enough".

Hitting the rotor, if you hit the 8inch from a botched sidehop, a 6 inch would get hit as well. I don't quite get how it's "more vulnerable".

No bashing or anything, just curious why it's "advised against".

[ogre]

the bigger the rotor the more there is to bend, theres no way you'd need 203mm for a mod, i had 203 on my stock and it was ridiculously powerful it's extra money for no gain, and it's extra weight and making the back end of a bike heavy isn't a smart move, large rotors are favoured cause they disperse heat more effectively than smaller rotors, heat is never an issue in trials it'd be excessive, plus it'd be expensive buy 200mm rotors all the time...

[CC12345678910]

heat is never an issue in trials

Comeing from someone living in lincoinshire where it's generally flat as a pancake. (Where I live everywheres a f**king hill & disc rotors warp in a second)

Whatever size u go for get one of these

http://www.wiggle.co.uk/p/cycle/7/Hope_Flo...tor/5360029666/

I will be when I eventually go disc & they come in nice pretty colours...

Edited February 1, 2010 by CC12345678910

[Will Arnold]

I know concerning the whole leverage thing with stock vs mod wheel size, but why would anybody say it's too much brake? I would rather have too much power in the rear rather than "just enough".

Hitting the rotor, if you hit the 8inch from a botched sidehop, a 6 inch would get hit as well. I don't quite get how it's "more vulnerable".

No bashing or anything, just curious why it's "advised against".

the fact is, a 160mm rotor IS enough for the back. a well set up hope mono trial with a 160mm rotor is so damn good... and even with a 160 i managed to bend my first one. i think i'd rather crap myself than ride with a 203 for fear of hitting it!

[Mark W]

Hitting the rotor, if you hit the 8inch from a botched sidehop, a 6 inch would get hit as well. I don't quite get how it's "more vulnerable".

Not always, especially as you don't generally go directly down on a rotor from a missed sidehop (and if you were going straight down, you probably wouldn't bend it). Because of the angle you go at, 160s and to a lesser extent 180s are more protected by your frame and tyre than a 203 is. Similarly, you need all the clearance you can get riding 'proper' natural, so I'd rather have a smaller rotor that's still plenty powerful enough, but have it smaller so it's harder to hit in the first place, but also harder to bend if you do.

Going back to the power thing again - you don't just want pure power in a rear brake, most of the time. 160s and 180s are definitely powerful enough, but for feathering a brake it's nicer to have the smaller rotors rather than a 200+ so you have more control with it. Again, that's more applicable to natural, and to be fair I'd say natural was a far, far harder test of a brake than you'd get on street.

[cai]

I used a 203 BB7 on the rear of my 24" (and yes, I can set up a BB7 very well - they are the only brakes I ever use on the front), for modulation it was good, for bite & hold however it was in no way as good as a rim brake set-up.

So considering the smaller wheel I'd say a 185 rotor would be acceptable, but don't expect to be blown away with 'power'. I can just see a 160 rotor on a cable opperated disc brake on the rear not being enough..