Tall bike questions
 

I want to build my own tall bike this summer. I have a few questions.

1. About the steering tube... Where do you get the longer tube? Any particular tubing you recommend? Dimensions ect...

2. If I don't have access to power tools was the best way to the rear triangle off the top frame?

3. Do they frames have to be the same size to get the right angles for the steering tube to line up?

4. Does the top of steering tube get welded to the fork of the top bike or actually welded to the steering tube of the top bike.

Thanks a lot!

use the search function then come back if you have further questions.

1. You have a couple options:

a) You can just extend the steerer up to another steerer. This will work, but bike will be flexy.

b) Create a long head tube between the two frames along with a longer steerer. This is my favorite way. You only need one headset (option (a) would use two) and the bike is much stronger.

c) Mate fork from top bike to stem of bottom bike. I've seen pictures, but never seen one in action.

2. Hacksaw will cut through any steel bike tubing.

3. Frames don't have to be the same size/geometry. The only thing that really matters is that the headtubes are lined up. You do this by lengthening/shortening the steering tube.

4. You have options here. I like taking the fork and welding a smaller diameter pipe into the steering tube of the fork. I then chop another steering tube and weld that to the top. This then runs inside the extended headtube.

A good way is to use a smaller pipe and jam it into the bottom and top steer tubes, weld away. This is WAY easier than any other method I have used, but you will have to add a brace between the top and bottom frames near the head tubes.

On mine I used a length of 1" gas pipe to section the original steerer. That is, I cut the original steerer in half and welded the correct length of pipe between the two halves.

this works well, if you have decent parts. also, this method requires no welding.

here's what you need(aside from normal parts. this is the list of stuff you need to connect the bikes):

one bottom stem, preferably steel, or a bmx or threadless kind, with a removable face...
one top fork.
one front hub, wheel and spokes removed, axle, nuts, etc, intact.

pry open or unbolt the front of the stem. insert the hub in there, and tighten the stem around it, like it's the handlebars on the bottom bike.
put the top fork thru the top headset, adjust tension like normal.

now, pretend the hub is your front wheel, and mount it on the top fork. tighten the axle nuts.

this will most likely put the seat pretty far back owing to fork/headset rake, but you can flip the stem, and/or the fork to help push the top frame forward, to keep from making it too back-heavy.

let me know if this isn't clear, and ican take some pics of my current setup that uses this doublestack technology...

also, you might wanna check out the photo gallery forum on zoobomb.org, that's where i got the idea.

i say just extend it using another tube