Hello all,
I've been planning to get into fixed riding for about 3 years now, ever since my university roommate introduced me to the idea. Circumstances and travel have got in the way, but I might finally be in a position to take the plunge. My main concern is about stress to the knees -- as it happens, I only have one, the other having been amputated as part of cancer treatment 17 years ago. Does fixed riding really introduce that much more stress to the knee than singlespeed? I don't particularly want to take the chance of screwing up a knee that already has to do much more work than usual, but the fixed gear sirens are calling my name...

I run 52x14 on my Dahon folder with 20" wheels, and find I'm quite happy with it (a bit of spinning with tailwinds, but nothing ridiculous). According to Sheldon, that gives me 74.3 gear inches. Does that sound like a reasonable number for fixed city riding in a place with no hills? Ideally, I'd like to be able to do *some* hills should I ever come across them.

My plan, if I'm convinced that I'm not going to kill my knees, is to figure out if I can get a fixed wheel built for the Dahon -- and if that doesn't work (hub spacing might be an issue), I'd like to buy a solid old Chinese steel frame (Flying Pigeon) and build something up around that. Could be fun.

Apologies for any newbieness in this question, and thanks in advance!