I installed a new rear tire on the wire wheel from my project roller last night, but when I went to put it back on the bike I couldn't get the brake plate to seat properly. I wheel had just been loosely installed before so I could roll it around, and I hadn't really paid attention to the fit of the plate.
After spending some time trying to sort out the problem, I used my micrometer to check the outer diameter of the wheel bearing hub and compare it to the one on my Lester rear. To my surprise the hub on the wire is about 3mm wider than the one on the Lester (about 74mm on the WW and about 71MM on the Lester). So the flange on the plate that centers on the hub bumps against it rather than going around, pushing the plate out a few MM.
Does the 750 use a larger bearing hub? The rim itself is a 1.85" wide rim, which is correct for the 550 and the axle diameter is the same as the Lester. I think this is the wheel that came with the roller when I bought it, but it is possible that it is the one that came with the basket case 550.
