Check out my signature for my build diary..!
I didn't bother with a diff- all the wheels are independent. As I was on a budget when I built ours, I made quite a lot of compromises that I wouldn't do now if I built a mark II- I started with two 'donor' bikes I picked up for locally on
ebay, but I think the only things I ended up using in the final build where the bottom brackets, derailleurs, chain rings and cassettes, and even they're not really ideal gear ratios. One thing I will say is get decent strong wheels from the off- mine are all 48-spoke 20" BMX wheels with symetrical spokes (as opposed to dished on one side to accommodate the cassette, although I have got cassettes fitted). Oh, and before you even think about going, think about how you're stopping...! I've got two dual-pull brake levers, one of which pulls the front brakes, the other the back brakes.
With regards to steering, you need to get your head around Peter Eland's spreadsheet first and foremost
Also, think about where you are going to take it. I designed mine to be a maximum of 1m wide at the widest point which gets us through most bollards, and it's also liftable between two people so that when faced with a tandem trap barrier or similar, we just hoik it over with one of us at either end.
I've just had the baby thrust upon me, so hopefully that's enough to get going...check out my build thread, then see what questions remain
I'll pop back later!
