Alt Bike Culture - Tallbike ideas/problems?

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RiotBoi
12-17-06, 01:13 PM
Hey guys, I'm planning to build up a tallbike for touring and I've run into a problem. I intend to use a tandem frame for the bottom and mount the top frame(standard road) in the middle of it. Thise should give me good wheelbase and balance for descents (viva mountains). Now the problem. how the hell can I make the steering link up? I'm planning on going to 3rd world countries with the bike so it needs to be simple and tough.
Thanks in advance
T.C.Rival
12-17-06, 02:09 PM
you could use a universal joint... or for a much simpler solution that is easily mcgiver able in the middle of no where... a rag-joint...
look to old VW beetle steering joints for both varieties... if you use 2 joints with a long linkage in the middle you should be able to avoid any severe angles that might bind... you should run some kind of stabalizer brace or something though... i would think
-pete
You could also increase the rake of the fork(s) so they line up. That would, of course, increase the stress on your headset(s).
Is having the top frame in the middle that necessary? Keeping the majority your gear over the rear wheel/behind the seat tube of the top frame should be enough to keep your center of gravity back where you want it to be. Not too long ago I saw a picture of a touring tall bike that had a loaded Xtracycle on the bottom. Looked like nothing short of hitting a 2 foot wall would have made it endo.
frameteam2003
12-17-06, 10:59 PM
Run a chained linked steering like they did on the old "steer from the rear tandems"
napalmandroses
12-18-06, 08:50 AM
you should check out www.tallbiketourbritain.com and take a look at their bikes
they had no problems with their frames and they are really friendly and would be willing to answer any questions
I think by putting a tandem on the bottom youre going to have it unnecessarily long. you can make it about 3/4 of the length and still be plenty sturdy
RiotBoi
12-18-06, 04:42 PM
I've already talked with those guys. One of my other problems is not having access to bike welders. My welder is a sculpture student and while I'm sure his welds will be strong, I don't want him having to make some crazy **** like their bikes. You see how many pieces the rear ends are? I may try and find a small tandem *shrug* I'll work it out.
Frankinbiker
12-18-06, 09:50 PM
I have made my share of "Tall Bikes." The best way is to make it from scratch. for the headtube just cut one long enough for your design and then weld the rest of the bike around it. I have a tall bike with a 4 foot head tube and it is made in a V so I can jump down if there are no traffic lights to grab. Fabrication from the ground up sans BBs and drop outs is the way to go with alt bikes. Learn to weld if you don't trust the sculptor. I am a sculptor and I never had a bike break including homebuilt tandems and the invisible bike.
I think by putting a tandem on the bottom youre going to have it unnecessarily long. you can make it about 3/4 of the length and still be plenty sturdy
Agreed. It shouldn't be too much extra work to stretch a regular bike a few inches. Once you load the rear down with gear you'll be golden. In my experience the trouble with tall bikes isn't endo-ing, it's having the front wheel come off the ground (ie when climbing). Extending the rear would take care of that. What you are proposing is going to be really heavy and unnecisarily so. Be sure and update us whatever you decide to do!
Johnny Payphone
12-30-06, 01:31 AM
In my experience any remote-steered tallbike is a deathtrap. You wanna come down mountains with this thing? Just angle the head tube back a little bit.