We get quite a few emails about the cost of building a buggy and the lists of materials that are used in the chassis. Here is some brief information that will hopefully help answer these questions.
Chassis Build Costs
Overall the build cost of the chassis will depend on the amount of time you put in vs using your wallet to do the work. The bulk of the cost of Rorty (or any) buggies is the parts you put on them – motor, reverse box, shocks, wheels, tyres etc. Our buggies are aimed at racers and those that want the best performing buggy they can build. We generally only specify quality parts and materials that are up to the task and our designs reflect this. You can substitute any parts you like, however, we recommend sticking with gear of the same specifications.
Our advice is to consider your overall budget realistically and then look to buy the best components you can within your budget. The cost of plans and of chassis materials is important but in the scheme of a buggy build the chassis and suspension arms can constitute as little as 10% of the overall cost of the build.
Chassis Build Materials
Our designs generally specify 1020 DOM of various sizes for the main chassis tubes and 4130 seamless tube for the suspension arms. In some countries (including Australia) DOM can be tricky to source (we’re working on it!).
Cold drawn seamless mild steel tube (CDSM) is a suitable substitute, as is ERW350 (350Mpa with a weld seam). ERW250 (250Mpa) is also suitable but might restrict competition use in some areas.
CrMo 4130 is generally easier to source in all required sizes as its used extensively in the motorsport and aircraft industries but is more expensive. It is essential for the suspension arms (as specified) as it is better able to stand up the punishment they get. We only recommend TIG welding 4130. Stress releaving of the constructed components is usually not necessary for thin walled tube structures where good welding practices are employed.
Mixing material types (as long as they’re all steel) is possible although you’ll loose the benefit of the stronger (more expensive) material in the overall structure. This might not be an issue if its not a highly stressed area of the chassis or if you are using a few tubes of 4130 in a DOM or mild steel tube chassis because of supply issues.
There is plenty of information available so do a little research if you need further information. We recommend published information rather than forums which can be full of keyboard experts!