Riding my bike
Join Date: Aug 2006
Location: Bi-Coastal Bays (Boston & SF)
Bikes: Giant TCR C2 / Bianchi "beater"
If you only want a bike for one day, don't overlook Bay City Bikes and/or Blazing Saddles. They may be a little touristy, but I've rented road bikes from both of them (as well as Mike's Bikes) that were very serviceable. No problems with bringing my own pedals (etc) with any of them. BCB & BS have locations quite close to Union Sq.