IMHO only one choice and that's Doha bisiklette. I went to the other guy on a Tuesday when Ali was closed, hired two bikes for a trip into Fethiye and one had a flat tyre before we got half way and the seat fell off the other one which made the ride back to the shop very uncomfortable. The guy refused to give me any money back even though we had hired them for the day but only had them for about 30 minutes. Needless to say I'll make sure that I go to Ali's in future.