Triangle Bike 1

Triangle Bike
Fun Bikes that you can make yourself!

First attempt at the Triangle Bike with Steering tube running through the seat tube of a bike's rear triangle

Short Wheelbase and steer from behind handlebars make slow speeds exciting.

Concentrating while learning to ride the Tri-Bike

Bannana seat is held up by an old crutch as the sissy-bar.

Triangle Bike

Frame Materials: Back half of a bike frame with the seat tube cut and repositioned behind the BB shell and used as a head tube. half. Another bike's seat post holder is welded onto the new "seat-head" tube. It also has an adjustable sissy bar made from a discarded crutch. Bannana seat hangs from crutch by a rope.

Weight as pictured: 30 lbs

What was I thinking?:

I'm trying to make a mass transit bike that is compact and does not need to fold. I want to simplify the bike down to a rear triangle. The purpose is to experiment with upright rear steering, seating, and pedaling geometry as a proof of concept.

How Does it ride?:

In the configuration shown its difficult to ballance and requires lots of concentration. It has a far back CG that makes it easy to wheelie. It has awkward ergonomics and excessive trail with a shallow head angle. It has lots of steeering friction and sometimes gets away from me in a turn. There is some pedal wheel overlap using the big 12" front wheel shown. You have a funny feeling that you are riding on your own handlebars.

What Changed before the photos?:

I started with and may return to an 8" front wheel from an electric scooter. I keep reversing the fork to test different trail dimensions. i started with a regular bike seat but i felt my CG was too far forward.

What may change later on this bike?:

I want to test 20" and 24" back wheels to steepen the head angle.

What would I do differently on another attempt?:

I plan to build a plywood triangle version similar to the plywood bike for testing "seat-head" tube angles and wheel base changes. This bike design is in uncharted territory, and the convertability of the plywood bike design should help.

What lessons were learned?:

It works ok as an experiment. but its not practicle yet. It is easy to transport.

What are the keeper developments?:

Combined Seat tube and Head tube. Bannana seat to test different CGs. Sissy bar made from an old crutch

It is cool to see the simple bike form without an obvious head tube.

tomkabat@aol.com