Check the rear triangle bearings. With the bike unfolded and wheels on the floor, press sideways against the bottom bracket and see if there's any play. If there is, walk away or ask for a significant discount. Replacing the rear triangle bearings is a fairly major job, which requires either lots of time or specialist tooling.
Thanks! What should I ask the seller about before asking to view the bike in person that will tell me about the state of the bike and value for money?
Thanks! What should I ask the seller about before asking to view the bike in person that will tell me about the state of the bike and value for money?