Cell phone
Actually these bikes are very dependable, so far only need I had for tools was of my own doing. Put a tire on Wendys bike and it was lowered 2". Well the tire was too tall even though stock size and rubbed on the fender. Had me puzzled for a bit since it felt like I was riding with the break on. It would spin free on the jack and on the ground, it even spun free when I sat on it but once I got up to speed and the tire expanded from centrifugal force it would rub. Pulled the caliper along the road and rode it, still happening. Did many such adjustments along the road trying to figure it out. Once I got home and got the tire off it was obvious that the tire had been rubbing on the fender in the center. Trouble was you couldn't see that with the tire in place.
