185 or 203mm Rotor upgrade?

GTi-R23

I've got Juicy 3s and 160mm G2 clean sweep discs front and rear, I'd like to upgrade my front disc as I'm a fairly big chap (6ft 2, 13st) and like alot of braking power.

Bascially, will I notice a difference going for the 185mm or should I go the whole hog and get the 203mm? My fork (Reba SL 09) will take up to a 210mm disc, but will a 203mm put too much extra strain on it?

Pros and cons of each would be really helpful, I have done some searching, and alot of people seem to say the 203mm is overkill?

Thanks in advance.

The Northern Monkey

I always thought that the max rotor size was due to the position of the mounts on the fork and clearance... I may well be wrong tho!

GTi-R23

Yeah well my fork manual says the forks will take up to a 210mm disc, so I'm not worried about the actual fitment, it's just whether the 203s would be overkill and put additional strain on the forks and whether the 185s will be a noticeable upgrade from the 160s

dave_hill

If the fork manual says it will handle 210mm discs then why would a 203 be too much for them?

BTW bigger discs don't actually give you more power - they just cool more efficiently allowing the brakes to work properly for longer.

dave_hill

bigbenj_08 wrote:

I always thought that the max rotor size was due to the position of the mounts on the fork and clearance... I may well be wrong tho!

Come on Ben, you're a clever chap, think about it...

The mounts on the forks are always the same (they might be different axially, but radially they're always the same) - you use adaptors to space the caliper off the mounts to account for the different disc diameter and whether the fork has IS or Post mounts.

xtremedash

203mm is a very large rotor, suited to DH and very fast tough descending. You would definately see the advantage from 185mm rotor. I'm a similar size to yourself and have a 203 rotor on my spesh pitch. It's greater when flat out down the steep stuff, but I would be just as happy with a 185mm.

The Northern Monkey

dave_hill wrote:

bigbenj_08 wrote:

I always thought that the max rotor size was due to the position of the mounts on the fork and clearance... I may well be wrong tho!

Come on Ben, you're a clever chap, think about it...

The mounts on the forks are always the same (they might be different axially, but radially they're always the same) - you use adaptors to space the caliper off the mounts to account for the different disc diameter and whether the fork has IS or Post mounts.

Oh god. I don't even remember posting that! 9:40 is too early after 1/2 a bottle of JD

Nice to know someone thinks i'm clever though haha

M1llh0use

I'm on the heavy side of 14stone and have got a 203front/185rear setup on scott scale and it's really good, massive stopping power with single finger stoppies!

recommended!

supersonic

dave_hill wrote:

If the fork manual says it will handle 210mm discs then why would a 203 be too much for them?

BTW bigger discs don't actually give you more power - they just cool more efficiently allowing the brakes to work properly for longer.

They give you more 'stopping' power for a given lever effort by means of a longer torque arm. Or another way of looking at it is the outer edge of the rotor is traveling faster, so more friction for a given lever effort.

It will feel sharper, and maybe not as well modulated.

Also some forks have specific mounts for a rotor size ie the Totem, will take only 203mm min.

GTi-R23

Ok thanks for the advice guys, think I'll go for the 203mm then and see how I get on, I quite like sharp brakes, I like the feeling of either on or off, I'd much prefer the brakes to be too good rather than merely adequate.

I knew bigger is always better