DX 11 Gent

Model # 1

This bike is not just a replica, it is a completely re-thinking of Mikael Pedersen's design.

Fons op het Roodt Website

Maker and owner Fons op het Roodt, Industrial designer (NL),
Dutch Pedersen Genootschap member.

Photos and text courtesy © Fons op het Roodt.

In Dutch, when you say "DX11" it sounds like: "I did it myself".
So, the name is just a joke.

I ride it every day (when it's not raining!).

The first time I saw a Pedersen was an article in the German design-magazine FORM back in the nineties. This was my bike! So when I decided to build my own bike for the sitting position it had to be a Pedersen-like.
The start of the bike was my medical and ergonomic interest in the sitting position on a bike.
It's a long story and the short version is that the next best to walking is a straight up position on a bike. By moving the pedals in the design backwards, you address the back forces from the pedal force straight into your body. By doing that there is no lost energy during biking, as long as you stay in the low range of energy-input. Up to 20-23Km/h works fine.

Enlarge photo (61 kb)

It is very true to the original first drawings, when you disregard the saddle. The front-fork is turned 180 degrees. I think it looks just right. (Editors remark)

Stainless steel tubes 12mmx1.5mm
15Kg including umbrella. (Weight was never an issue, ease of building (suchs as welding) is more important for a first model).
Homemade 11 gears in the back [11/32], one sprocket in front [one grip shift].
Combined hydraulic brakes from Magura on one handle, tested on ice for safety.
Rubber suspension in front. The lower triangle of the frame bends during suspension. It has a small travel just for comfort.
26" mountain bike wheels from Shimano with wide slick tires.
Homemade wooden fenders.


Enlarge photo

The design was entirely made on the sitting position with just the photo in the magazine in mind. I started with stainless steel tubes 12mmx1.5mm and ideas about brakes, gears and suspension.image
Enlarge photo

The theory was that in an upright position you could bike with one hand because you don't need to bring reaction forces to the handle bar. Therefore I looked to solutions for one hand. In practice this works very well.
I didn't want to use the saddle technique of the Pedersen. I think different about it. In my opinion it needs more comfort and more movement sideways. So I used an normally saddle with rubber suspension in the back and polyester flex tubes in front of the saddle. Now the saddle can move and rotate with my hips in any direction but not forwards and backwards.
Adjusting it to my weight and length was the hardest part of all.


There is a future.
For my girlfriend I plan a Pedersen with 20" wheels and electric drive-assistance. To solve the problems of girls-closing the saddle must be lowered during stops so you can walk over it from behind. In that way I hope to overcome the problems of the necessary flex tubes in front of the saddle.
For myself I like to redo my own design in a lightweight-form made from carbon tubes and aircraft aluminum.