And the ironic part is that I don't think I needed to change it. The tire was slack but wasn't completely flat. I should have tried to blow it back up but didn't think of that - rookie mistake. Anyway, got the tire off without a problem, had a hard time getting the new tube in, and my girlfriend actually punctured the extra tube. So, we had no alternative to put the original tube (the one that went slack but wasn't flat) back in - and of course had a problem getting that in. Finally got it in, inflated it, and was able to ride it back home. Is there an easy way to get the tube in? Any tips? Thanks in advance to all.