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Originally Posted by roman415  Just would like to give this a bump. I am a newcomer to the forums and am planning to install one of Dax's 70cc kits on my Rock Hopper mountain bike.
The Rock Hopper has disc brakes, and I was curious if any has gotten this to work.
It looks like I will have to ditch the rear disc brake if I go with the traditional spoke hub install (the brake itself doesnt look like it would clear the new sprocket)
For some reason (correct me if I'm wrong) I get the impression that you would be able to mount the sprocket to the actual rear disc, rendering it useless but providing a solid mount for the new sprocket. Does that make any sense?
I have another set of non-disc brakes that I was going to slap on in the rear but keep the front disc.
Thanks is advance |
Funny, I've got a Rockhopper too... about, oh, 10 years old (My goodness, has it been that long?!?) With Sun Rhynolite rims and Shimano XT disc hub with 9 speed cassette. The engine's driven sprocket's inner hole was smaller than the wheel's hub body. I grinded off about a 1/8 inch off the sprocket's inner radius to slip it over the hub and up against the disc rotor mounting lugs, but when the wheel was mounted, that put the sprocket hard against the frame...so I ground off the hub's disc mounts altogether to spoke-mount the driven sprocket, and it cleared fine.
If
possibly you've got an old 7 speed arrangement, the wheel's dish might be reduced enough to move the sprocket closer to the "center"....but then again, I don't recall disc brakes readily available when the 7 speeds were around, but possible when 8 speeds were popular.
Note: My Rockhopper frame was right when they changed things around in 1997-ish, when I snapped the frame. It had a short one inch headset for threaded fork, but when warranty-replaced, was sent taller headtube updated to 1-1/8 for threadless forks....where was I going with this??????
I guess just reminiscing about the good old days when I used to pedal instead of motor around!