My school is building our second car, this one a cycle car, our first had four wheels and we just fixed it so we are still new to building, so my team has a few questions:
What type of axle should we get?
How much support would be needed? (The weight will be around 60% back 40% back, the best we could get it)
How big of a wheel will we need?
Would suspension be something to consider, if so will the motor need to be on the same system as the rear wheel?
Our frame is 1 x 1 inch hollow square aluminum could the rear fork be made with that, or do we need something stronger?
Could we take the rear fork of a rigid / softball mountain bike?
If your team has not looked through th Electrathon Handbook which come with registration or is available on line then I would advise you to look through it. It will answer a number of your questions.
-At Willamette we make nearly all of the parts for our cars in our metals lab and nearly all of our cars are out of mild steel to cut down on cost since we make so many each year. We usually use 1" X 2" rectangle tubing with 0.065 to 0.093 wall thickness. Most of our cars have a straight axle with the kingpin on the ends set at the correct angle for best steering. About 1 in 5 have a 'drop axle' which has advantages and disadvantages. The straight axle is like the ones shown on page 19 of the Electrathon handbook.
-We also nearly always use 20" bike tires and wheels. We like the Tomos moped wheels for the front that come with 12 mm bearings, drum brakes and fit the 20 bike tires. We have used 16" wheels at times on a few of our past cars but for us and our fleet of 17 to 20 cars a year it is easiest if some things are uniform across all cars. See page 22 and 23 of the handbook.
-We have only made a few suspension cars and most of those have been of the solid rubber bushing type. Most of our cars have hammock or suspended seats for driver's comfort and that is usually all that is needed and we race on some very old and pot holed parking lots that are probably rougher than anything other areas race on. Page 20 of the Electrathon handbook has examples of this.
-For you back fork, yes you can make it out of aluminum tubing or a rear bike system could be attached. Again we make all of ours and a couple of examples are shown on page 21 of the handbook.
Again if you want to contact me by email I can send some pictures and more information on our systems...which probably are not the best ones out there but they work for us.
