Recumbent #1

First Recumbent

posted in: Recumbent Blog | 0

This is my first venture into building recumbent bikes. It is a long wheel base under seat steering bike that looks somewhat like a Ryan Vanguard. The frame is aluminum 6061-T6 and the fork is from a kid’s bike. Wheel set is 26/20, seat is mesh on frame with a solid pan. There is aluminum handle bar that pivots under the seat and is equipped with common bike brake and shift levers. A drag link with spherical rods ends links this to the front forks. Sounds odd I know, but it is an amazingly comfortable bike to ride! The handle bar grips are located at the spot where your hands would fall so it feels quite natural. One of the draw backs is that if you need to turn sharply the bar end on the inside of the turn can hit the seat while the hand on the outside bar end can hit your leg. So….in the proven practice of “if something works, it should be messed with”, I decided that a better method might be to use a geared system where the bar ends pivoted on the same axis direction as the wheel axle. In this case, pushing down on a short forward facing bar on the right side, would cause the front fork to steer to the right. Pushing down on the left would have the opposite reaction. And the two bars were geared together under the seat so when one went up, the other went down. with a little practice this proved workable but only with heavy concentration. For several years there were dark hand prints on the long hallway walls where I work, as a testiment to how long it took to learn. The first real ride on this animal was at our (at that time annual) recumbent ride. I got going okay but the first time I got up to speed I discovered that at the point where front wheel gyroscopic effects became noticable, counter steering would be required. On a conventional bike you can pass through this zone without really being aware…..no so with this. While moving a lever one way would cause a right turn at low speed, at some point turning the wheel to the right as speed increased meant that the bike would lean left and turn left!!! So if you were coasting down a hill and approched a pothole it wasn’t obvious which way you had to push or pull to get around it!
I lasted the entire ride without a collision until I got back to within a kilometermor two of the start. There was a car following me that refused to pass (no real surprise there…) and it became so distracting that I couldn’t concentrate and over I went. Going slow enough by that time that I lost very little skin but more than a little bruised in the ego. So…….The next day I fabricated a system like everyone else was using and had a great time on the bike until I got the desire to build another one.

Leave a Reply

Your email address will not be published. Required fields are marked *