Check Out this Wacky Square-Framed Fixie Bike

Bikes Workshop
Check Out this Wacky Square-Framed Fixie Bike


Bicycles are normally made out of round tubing, but there’s really no reason that square tubing couldn’t be used, as seen on this bike made by Aaron Seiter and based on Michale Ubbesen Jakobson’s “BauBike” design. As Seiter puts it, after seeing Jakobson’s bicycle, he “fell in love…The design is so clean, simple, and honest.”

Somewhere in the back of my mind, I keep thinking that there’s a structural reason that round tubing is preferable, but it’s been “several” years since I went to engineering school. Tubing shape aside, Finding the weak points on this unique and very square frame would be an interesting statics problem. According to Seiter, however, he has “put the bicycle through the ringer (off curbs and over speed bumps) and so far she has held up very well.”

It’s definitely a very interesting and visually striking design. The chain is quite long and the powertrain is a “fixie” design, where the rear wheel will not move without the pedals turning. This configuration can substitute for a rear brake, which is good since this bike does not have traditional brakes, and Seiter doesn’t plan on adding them any time soon.

Here’s a video of this bike being ridden quite successfully, and even without hands at one point. Very cool, and very unique as Seiter desired.

YouTube player

[via Reddit]

2 thoughts on “Check Out this Wacky Square-Framed Fixie Bike

  1. George Carlson says:

    Nice work. I think the main reason bike are made with round tubing is that it is cheaper, and fits well into round where it is brazed. Squares are nice, but triangles are better. The strength of the frame would increase dramatically if that vertical fork section at the rear was angled forward making a triangle. Square inside corners are stress concentrators, so be careful.

  2. Simon C says:

    Pace cycles in Yorkshire used to make mountain bike frames with square tubes. They can be externally butted using a milling machine and the legend is they were used because they didn’t roll off the table when welding!

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Jeremy is an engineer with 10 years experience at his full-time profession, and has a BSME from Clemson University. Outside of work he’s an avid maker and experimenter, building anything that comes into his mind!

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