How big is the lever that's "too big"? My lever was too big, but it came with rubber shims that made it only "slightly too big". Electrical tape solved the problem. Just go over the part of the handlebar that the brake lever would go around, a couple times with the tape and then put the brake lever on. It works pretty well. The guy at my co-op also suggested cut up beer cans, but I like the electrical tape idea better.