Got a question.

I'm fairly new to riding in Toronto and am coming back from a hernia, 8 months off my bike, and hernia surgery. 48x16 wasn't so bad when I lived in Madison, WI and was in great shape...however, I've caught on to the fact that north is uphill here, and that I'm now shockingly feeble.

I want to drop from 48T to 42T. I've worked on my road bike lots. Haven't worked on my fixed gear so much. Any tips on how to shorten the chain and generally make this thing work without ******** anything up too badly? Any replies, messages, or pointers toward other threads w/be greatly appreciated.