Gear inch/ratio question

You've never ridden fixed and you want to ride brakeless?
Use your brain dude.. and I don't mean by putting it through a taxi!

70GI(ish) for London.. as has been posted about 4000 times on this forum

Gotta start somewhere, don't I, Of course I wouldn't throw myself out in london traffic on my first day on a fixed without breaks, or the week after for that matter, it's a learning experience just like anything else. But I reckon if I wan't to ride fixed without breaks, the best way to learn is to actually do it, no?

70ish it is then, thanks.