Tighter bolts and restricted bearings are not a good fix. For a reliable fix use longer bolts and lock nuts or carefully selected shim washers. Either of these fixes will solve the problem and allow bearing to spin free.
Lock nut fix: http://www.unicyclist.com/forums/showthread.php?t=101676
Shim washer fix: http://www.unicyclist.com/forums/showthread.php?t=121500