This is an update of my former instructable http://www.instructables.com/id/Row-pull-push-bike-la-marianette/
After a year of daily work and more than 1000 Km the hinge was wearing out making steering unprecise. So I decided to rebuilt the mechanism and try to make it even stronger.
Many people watched the original instructable last year but nobody told me about doing something similar. I hope this one helps somebody to try it. The bicycle is really fun and many interested people ask me about it in the street.
The new hinge is built using a wheel hub, a handlebar stem and a front fork.
Hub diameters are not standard.
The diameter of the hub should be similar to the diameter of the handlebar stem.
The spokes of the bicycle wheel are dismounted. The hub is kept to be used as a bearing.
The stem clamp was opened using a big screwdriver and pliers.
Of course you would not do that with an aluminum stem!
Aluminum stems have usually a two pieces clamp, this step would not be needed. However, matching the diameter of the hub would be more difficult.
Hub into the clamp.
Clamp closed with pliers.
Clamp screw inserted and tightened.
The stem is mounted in the bicycle
The fork is mounted on the hub.
The handlebar is fixed to the fork using another stem.
A pedal is fixed to the fork. I used a crank shortener and a couple of seat clamps for that.
You may also find a way to fix a spare crank to the fork instead.
I used a satellite clamp and a M8 threaded rod to couple the pedals.
The front crank is now fixed with aluminum profiles. The profiles are screwed to the fork using the mudguard hole and a seat clamp fixed to the stem.
I changed the elastic ropes by springs.
Finished. Steering is really better. I hope it will work for another year.