Hi All,
I have an older cannondale lefty with a 4 bolt front hub. The discs are magura Julies. 180 on the front and 160 on the back. I need new rotors which are very hard to come by in Australia. The only 4 bolt 180 mm I could get was a Hope mini. The depth of the rotor circumference (where the pad does its work) is significantly less than that of the original julie rotor. The hope maxes out at 14mm and the julie rotor is a constant 17mm deep.

Will the hope rotor work ok? or should i toss the 4 bolt hub and look for a 6 bolt replacement.
Any and all comments welcome
Cheers
Jock

I dont know for sure, but I would SERIOUSLY doubt you will have any problems using the thinner rotor.

so are you saying there will be lots of extra pad overhang??

That is absolutely right. Lots of pad overhang. Incidentally the new hope rotor is a bit thinner than the heavily worn magura rotor. Why are the newer style of rotor so much thinner and alos have less braking area than the old magura rotors?
Cheers

well, here is my OPINION but i do not know if it is solid advice. generally, i would say if the rotor braking area doesn't match the pad sweep area, then it is not a good idea. however, it would probably be okay as long as the caliper piston is not overhanging as well. don't forget that the braking probably won't be as good if all the pad is not contacting rotor. also, you might have to replace pads a little sooner due to the large "groove" worn into pad. you wouldn't want the pads to start touching each other.

when you say "thinner", are you refering to the thickness of the rotors or are you refering to a narrower "outer band" of pad sweep area on the rotor? i would guess it has to do with weight savings and better caliper/MC designs? ....and maybe the new rotors are a larger diameter?

at any rate, if the piston is not overhanging, it's probably okay. i wouldn't want like half the piston over the edge or something.

not sure if i really helped any....

Sounds like a lot of pad is coming out...is that what you mean since the rotor got thinner? That means the piston is coming out more then its used to be. If it is coming out TOO much, its not good. Your lever might be lower but that might be adjustable but piston coming out too much is no good. When you are braking and there its a huge gap between the pads and the caliper, dirts get trap and piston get stuck.