A downhill racer is an engineless go-kart with seating for one or two people. You can easily buy kits or plans, online or from a local hobby store, which might be a good choice if this is your first try. If you are an experienced builder or have experience bending heated metal or as a welder, you may be able to build your first downhill racer from scratch.
For go-karts, you need a light but sturdy frame, so you can use round and square tubing to put together your cart. How much you need will depend on your plans and the requirements for the frame. You will need a pipe bender, hacksaw and a grinder for the edges of your vehicle. If you decide to weld your own frame, you will need welding tools and safety gear, such as a mask. There are kits that come pre-welded. You will also need steering and braking mechanisms, at least one or two seats, and, of course, wheels for your downhill racer.
Kits and Plans
You can buy kits online from shops like Go Kart Heaven (http://gokartheaven.com) or WayCool Kits (http://waycoolkits.com) or even on EBay. A suitable kit should come with everything you need for the downhill racer, pre-cut and pre-bent, which makes them a good project for a beginner or for a person who doesn’t have access to welding apparatus. Once you see how one frame is put together, it will help you envision your own frame designs.
A basic downhill racer frame is lightweight but sturdy so it can handle the bumps on the road and the weight of the passengers. A downhill racer frame is basically a rectangle with two axles that hold the wheels. The box of the go-kart is placed over the top, though you can test the racer without a box. You can install a seat, sling or bench to hold the passenger. A roll bar can also be installed to protect the passenger and vehicle from any damage, though if you do plan to take off down a hill, a helmet, in addition to a functioning braking system, is a good idea.
You can download free plans or purchase plans from an online store or a hobbyist. The plans should include all of your necessary materials, sizes and recommendations on what to purchase.
A down hill racer is the next step up from a wagon and is a good partner project or basic welding experiment.