Recumbent bicycle build it yourself

If you are interested you can get the design drawing by clicking one of these links as .gif or Corel 9.0 format, it is based on myself ie. 1,90m male.

The bicycle frame is made of 57mm 1,5mm thick steel tube, the dimensions are the optimum in strength, weight and handling. It is CO2 welded together. Using a combination of used parts and new material the frame can be completed.

Building it is not difficult if you can:

• Work precisely.
• Can weld, or can have it done.
• Make a full size drawing of the frame on your building board.
• You know what components you wnat.
• If you are persistant.

My initial advice would also be to buy good quality components. It is not important to have all the latest models, but last years components will do. Of particular importance are the brakes. You will be travelling at high speeds and car-drivers will not see you (your only 1m high). So your safety relies on your ability to manoeuvres and quickly stop. Braking a recumbent bikes is easy, particularly fore wheel braking. You can apply maximum force, as the risk of overturning is negligible. Many speedcyclist use diskbrakes.

If you take a close look at the pictures and drawing you will see that I changed the chain from running along the front-wheel, to running over an extra set of guiding wheels. The chain running along the wheel highly diminishes the possible steering angle. Although it takes some time getting used to at slow speed and when starting the bike, it is absolutely irrelevant when at speed. Have a look at the steering angles you use when cycling.
I myself now wanted a more manoeuverable bicycle and have decided on the extra set of guiding wheels

This page gives some information about the design. I have also available a design booklet, with more pictures, more measurements and description of how to build the bicycle. This booklet is not completely finished, a PDF can be downloaded by clicking this link : Booklet

Several pictures are of the unpainted parts as these show the details better than the painted ones. From the response I get; the rear-suspension is one of the main reasons for asking the design drawings.

The system looks complicated, because of its 3D shape. More than 250 drawings were requested and several people told me they started building the bicycle.

I suspect many more have used the drawings to augment their own designs. These photo's should help.

I have designed the rear-suspension around scooter springs and dampers. They are easily available, cheap and durable. Another advantage is their length. This may sound strange when all the high-tech systems are short, but these more easily fit the place where you need them. Another advantage is that I absolutely wanted a suspension with two springs for stability. Some of the lateral load is now taken by the springs instead of the hinge.

This next picture shows how frame and rear-suspension bridge basically fit together. Only one spring is shown where two are needed. It is clear that the frame forks into two segments directly aft of the hinge. This to accomodate the springs. This detail is less obvious in the drawings. When you have bought your springs you will have to gauge their force/length ratio (or springconstant). If for example you have weak springs the travel of the rearsuspension might become too much. You will have to place the springs more towards the rear-axle than with stiffer springs, or you have to increase the angle between the frame and the suspension bridge to accommodate for the longer travel of the weak springs. The reverse is true for stiffer springs.
The axle system is designed for a vertical travel of the rear-axel of 50 mm. If you do any calculations regarding the stiffness of the suspension (which is easy) remember that I use two springs!!

I have made this picture to present an overview of the whole frame set. There have been several questions of people wanting to make the seat. This is one of the nicer jobs in making the cycle. First of all find bending plywood, you can recognize it in the shop as the only plywood that bends real easy (in one direction only of course). I use three layers of 4mm birch plywood,

Glued together with either polyurethane glue or resorcinol glue. As a mold you can use either your bike frame or separately cut molds. The basic shape of the seat can be taken from the drawing, but experiment a little and see what type of curve suits you best, the seat shape can be real individual.
Make the plywood-blanks large enough for exact contour shaping after gluiing. Using clamps and sufficient glue, glue the layers together, remember to protect your hands!, After the glue has hardened shape the seat. You now have several choices. Just paint the seat. This makes a hard but not impossible to ride seat. Glue polypropylene foam (like one of those thin camping sleeping mats) to the seat if you want soem comfort. Or glue what in europe is called dry-back foam to the seat. I always use method 2.