rotor size/ mount confusion. feeling thick. give me a hand.
so this is what im using. http://www.chainreactioncycles.com/shimano-mount-adaptor-front-post-to-is/rp-prod13743
to attach the caliper to the fork. (fox 40) It says on it for 180mm rotor only. I have a 180mm ice tech rotor on the wheel. yet when I put the wheel on, the rotor only just reaches the start of the caliper nowhere near far enough in.
any help appreciated.Posted 3 years ago
got a new canyon. its got brakes on I don’t want they have 200mm rotors. fitting my xtr trail brakes onto it instead. I have 160 and 180mm rotors for them. the rotor is nowhere near big enough
any way to make them fit or do I need to buy 203mm shimano rotors? if I buy new 203mm rotors will I also need different mounts for them to fit properly or will the current mounts be ok? I don’t know if they differ and im getting confused
thanks in a advancePosted 3 years agoSuperficialMember
It depends on the exact model of Fox 40s you are using, but I suspect they will have a “+20mm” post mount so a 180mm rotor will work withou any adaptor – just bolt the brake directly to the fork.
If it’s an older fork, it might have an IS mount in which case you need a 160mm adaptor in order to use a 200mm disc. In this case, I don’t think you can run 180mm rotors.
I have two pertinent questions though:Posted 3 years ago
1) Why are you changing the size of rotor? Just use the old rotors / adaptors with the new calipers/levers.
2) What sort of bike has Fox 40s and small (180/160mm) rotors? Seems like a weird setup.
hareydan. I am changing the rotors because I am also changing the brakes. from avid to shimano and want to fit shimano ice tech rotors not the crappy avid ones.
the bike came with 200mm rotors but I already own the 180mm ones so was going to fit them. with the xtr trail brakes it will be powerful enough.
I cant bolt the calipers to the fork as the holes on the fork point the wrong way for that. it does require a mount. I am only using a mount and not an adapter and a mount. but I am confused as to the meaning of each one which is why im struggling to exlain/understand my situation. I have never had a problem like this before.
the bike is 2013 with 2013 fox 40 rc2 Fit Factory forks.
thanks for responses and sorry for my confusion. im going to take some pictures in the morning and then you guys can see what im on about and see if you can help
cheers.Posted 3 years ago
pictures here. however I believe that oxymoron has just answered my question above. where do I get one of those things?Posted 3 years agoletmetalktomarkSubscriber
So to me it looks like your forks are set to take a 180mm rotor with an IS brake mount.
By using your adapter in the pics you looked to have moved your caliper out 20mm.
I would have thought that you needed a IS to PM 0mm. These tend to be found on the rear caliper when running a 160mm rotor (my recollection of AVID certainly).Posted 3 years ago
I actually managed to find as IS +0 and tried it with that and was still way out so I assume that the IS mount on the forks is +20mm so even with a +0 I will need 200mm rotors. which does finally answer my first question so I know now to buy some new rotors. hallelujah.
thanks all for your help and apologies for my confusion. I now know the difference between IS and post mount.
anyone want to buy 180 and 160mm ice tech rotors by any chance?
or trade for 200mm ones?Posted 3 years agocookeaaSubscriber
From what I can gather the 40 effectively has an IS+40mm mount which they like to call the “NEW DH International Disc Bolt Pattern” (only the 40 uses it I think), basically if you use a PM caliper with a normal 160mm Front mount it will take a 200mm rotor.
Thus to fit a 180mm rotor you need a front 140mm, or a Rear 120mm mount (if you can find such a thing) those will provide the right offset for a 180mm rotor…
Or there is this Formula Fox F40 Mount Adaptor It is £32.72 for the 180mm version though, so a 200mm rotor might be an easier/cheaper/better performing option TBH…Posted 3 years agocookeaaSubscriber
Its simply Fox being difficult for the sake of it and confusing things by moving an IS mount a bit further from the axle for no compelling reason.
In the good old Days* we had one simple mounting standard (that was 20mm different further out at the front than the rear)…. and a different one for the Boxxer…
*there were no good old days.Posted 3 years ago
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