amberwolf wrote:Optionally, as you say, a larger ID bearing could be used, if one exists that has the same OD. Or a different bearing with a ring adapter/spacer to fill the space the new one currently fills.
Good news! We got a big batch of spare covers and it turns out that the region with the protrusion for the disk mount is solid aluminum all the way through. So it is possible to simply bore out the original 11mm deep bearing cavity to a full 18.5mm or so. This way, the location of the ball bearing ends up being exactly at the same spot on the axle as it was with the curved non-disk side plates, and no axle machining or special bearing adapters are needed.
In the original disk side plates, cavity for the ball bearing is 11mm deep so that it sits more or less flush:
Disk plate is precisely centered on a lathe, and then the 35mm bearing hole is extended further back:
Cavity now extends down to a little over 18mm deep
The ball bearing no longer sits flush, but is recessed to the right depth for where the bearing would be in the standard side cover:
Do you think the new rear sprocket side cover will fit the front 2807? I'd like to be able to try out a disc cover (front or rear) and a sprocket cover on my front 2807, if they'd fit.
So, that was the next moment or truth. I removed the side cover from a regular front Nine Continent motor. Replaced it with the modified disk version from the pictures above, and tried it out in bike fork. The disk sits about 2mm further to the right than would be ideal, but in this case there was enough side to side adjustment in the caliper mount to get it to align without rubbing the pads. In other cases, you could put a couple inside washers on the disk side of the axle to make the spacing better. So yeah, it works:
These narrower covers could allow me to use this motor where I might not have before, and use a disk or sprocket on either side without drilling into the cover itself.
I think so! -Justin