Step 1: The Chassis
The chassis was a simple "Ladder" design made from 19mm aluminium square section tubing. This is easy to work and light as well as moderately low cost.
The various sections were joined with aluminium plates and pop rivets. We followed a Greenpower design as the basis for our car but made numerous changes along the way.
Step 2: The steering
The front wheels have a simple bent 2 mm mild steel king pin arrangement with a 19 mm bolt though for the king pin. With plenty of grease this works well. the steering rods have trackrod ends easily available from bearing suppliers to allow a certain amount of give in the system so no complicated alignment was required just set the wheels straight ahead.
We decided not to apply any toe in or wheel camber. the wheels are a 12.5 inch by 2.25 inch wheel chair wheel. Again, aluminium for lightness and ease of obtaining new tires.