Hi, I've got a Mongoose Somethingorother (approx. 21spd hybrid with motorcycle style grip shift shifters) that I'm trying to fix up to give to a friend. I've adjust the rear derailleur but still, the chain skips on occasion, as a regular occurence, and what I'd like to know is if the problem will be fixed if I buy a new chain. Perhaps it might help if I said I left the bike out two winters, and its all rusted to hell now. Just don't want to buy a new chain if a lot of other expensive parts need to be replaced to eliminate this skipping problem; because then it'd be more cost-effective to buy a used bike on the cheap, that's in better condition (ie. a new freewheel would be a dealbreaker). Reason I'm fixing it up instead of buying a used bike, is that my Mongoose hybrid is the type of bike we were looking for.
(BTW, are Mongoose exclusive to Walmart? Don't know where the bike originally came from, but it seems the quality of the components and all are better than a typical Walmart bike).