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How to Build a Tall Bike, one that you can stop safely, and could be construed as street legal in most places. With this method, you'll be able to stand over the bike, allowing you to hop down easily, have two brakes, a full complement of gears, And have a better riding position than two bikes stacked on top of eachother. You'll only destroy one bike, The top portion is bolted to the bottom bike, so if it breaks, or you get tired of it, the bottom bike can be reverted to normal. All in all I think this makes for a suprisingly sane tall bike. Not that you'll look any less the madman riding it through traffic.
Step 1Gather two bikes, extra bits
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You'll need a pretty functional bike for the bottom, and a bike for the top that just needs a good bottom bracket, and a frame that isn't rusted away. I prefer cheapish old mountain bikes.
As far as parts;
"steel seatpost to fit the bottom bike
"full length brake housings/ one normal cable front, extra long cable rear
"handlebar/stem cobo to reach 28-32"
If you want to get multiple gears running you'll need
"two farly well matching drive side cranks
"extra long gear cables
My friend Topher actually built a pirate ship around one of those.
http://www.worldisround.com/articles/182375/index.html
This is from last year's fleet.
http://www.atomiczombie.com
Check out these crazy guys....
http://www.tallbiketourbritain.com/
http://www.peraves.ch/schwarze.htm
This wolud be the perfect place to show how something like that was made.