Rotor size

[big.eck]

the adaptors in that picture look like there to be used with 160mm :?

but you can buy diffrent ones if need be

 

[the great roberto]

Dunno if this helps or not.

In the car world often the same caliper will be used with a variety of rotors and suitable spacers.So, the calipers on my Passat will also be used on a audi TT, albeit with bigger rotors and spacers.

Same(ish) in the bike world. The spacer thing to mount the caliper further out to suit a rotor is ugly,but cheap.In the car world only cheap tends to matter.

Clearly the further out the caliper is mounted,then more braking torque can be applied.i.e. the Force, F is the same, but as it is at a greater radius,R then more F*R (N*M ) can be applied.
This all works well up to the point something fails...............Fastners, frame,spokes ?

If V brakes could apply more force effectivley then disk brakes would never have been invented, as they operate at a hugh( relativley) radius. Problems here are that they can't apply the force F that is required usually due to lack of effective friction (especially in the winter !).

Poor calipers like bigger rotors, to overcome their poor-ness.

I had a set of manitou mars forks that would only allow a max of 160mm dia rotors. With 28mm legs I expect that was wise. Another reason why 36mm and 40mm dia legs will have little problems with 203mm rotors

 

[the great roberto]

These brakes

http://cgi.ebay.co.uk/KOOKA-CABLE-D...sure_cycling_bikeparts_SR&hash=item3a5afc9ff7

Proberbly work fine. Them rotors are a work of art(not). I'd expect anywhere between 200g and 250g for each of those............But they could be changed if weight was an issue.

Most will vote for Avid BB7's as the best cable operated brake ?

 

[IDB1]

I know the brakes work fine.. with reports that they are as good as, if not better than, Avids..

Just needed to know whether the rotor size was dictated by the caliper or not really. . .

 

[MikeD]

Which makes me wonder why you asked 'what brakes' since it would appear not to matter??

It affects what adaptor you need, and may mean that no adaptor is available. If you want to fit a Shimano IS caliper to a post-mount fork with a 160mm rotor, for example, you'd be out of luck.

 

[IDB1]

Which makes me wonder why you asked 'what brakes' since it would appear not to matter??

It affects what adaptor you need, and may mean that no adaptor is available. If you want to fit a Shimano IS caliper to a post-mount fork with a 160mm rotor, for example, you'd be out of luck.

Gotcha. . .ta

Those Kooka's will be ok for fitting to Z2's though won't they??

 

[MikeD]

Should be. Hard to tell from the picture, but it looks like they might be post-mount like Avids, with an adaptor to go to the IS mount on the Z2s (assuming that they're 98 or later Z2s rather than really early ones with weirdy non-standard mounts). So you'll need to find a different adaptor to run a smaller rotor. Avid adaptors should work.

 

[Neil G]

Which makes me wonder why you asked 'what brakes' since it would appear not to matter??

It affects what adaptor you need, and may mean that no adaptor is available. If you want to fit a Shimano IS caliper to a post-mount fork with a 160mm rotor, for example, you'd be out of luck.

You can run IS calipers on modern post mount forks with an A2z adaptor but it's not pretty and heavy.

Personally I don't think you can have too much power as it just lets you use less effort at the bars. I'm running 160 out back and 180 up front and it's a good compromise if you fancy giving it some stick on the downhills. I think 200mm is more suited to heavy freeride.DH/bikes

 

[dyna-ti]

Fork/frame warranty. Chainstay clearance. Rider's aversion to enormous bolt-on caliper adaptors ;-)

Hang on :shock:
This ones directed at me and it nearly slipped through my image net
Tis tosh,bolt on are the real deal


To help out i have a c2 185mm rotor on the Z2 i have,and i cant see why a larger rotor cant be fitted to your z2.rear end depends on clearance with the seatstays but on the front a big disc is preferable
For me at least
More power up front the better

with reports that they are as good as, if not better than, Avids..

Cantis are better than avids and a damn sight easier to set up too

 

[IDB1]

Thought the BB7's were the benchmark in cable-operated discs until the Kooka ones came along :?

Going to use whatever rotors are on the wheels I have.. until the disc brake penny drops