Single speed chainring conversion

[sidmarx]

Actually the bike was already a single speed but the gear inches were too high. I chucked out the heavy steel stock crankset & had cassette brng. alu cranks put in with a smaller (34 tooth) chainring and the longest pedals i could find. (17 mm.)

Problem is that the chain line isn't quite straight. The freewheel needs slight spacing out from the hub, and that won't work without sacrificing the freewheel's thread bite. Also, any spacer wd. have no backing and hence butt up against the spokes. (there's no adjustment play at the crankset, wh. is already flush with the frame)

Is there anything doable? if left as is, am i looking at more chain wear than if it led straight?

[DaveM]

Re-space the rear axle and re-dish the spokes or get a BB with a shorter spindle.
A spacer behind the freewheel (if the right size) would butt up against the same shoulder the freewheel does, so it shouldn't hit the spokes. But, you're right, more than a couple mm of spacer weakens the freewheel to hub junction.

A little misalignment of the chainline (<1 cm?) is probably OK. Maybe more chain and chainring wear and higher chance of chain popping off.