In this article we will be going over the things you can do to make your speed car go faster and be more stable at high speeds.
I have currently got a modified Tamiya TT-02 that I use as a 50+ mph basher. It is fun and really great to drive - but I will be getting something more suitable for fully blown speed runs in the coming weeks hopefully.
So what are the factors that should make a good speed car?
Low centre of gravity
The car should be nice and low to the ground (without being too low). All the major heavy components are placed as low in the chassis as possible. As well as this, the base of the car should not be too narrow. This not only aids the handling, but it helps keep the car as stable as possible at higher speeds. The diagram above illustrates this in a simple way.
Body shape/aero
The shape of the body is essential to the success of a speed run. As the car increases in speed, the air is rushing over the top of the body at an ever faster rate. If the body is not streamlined then the air will in effect hit a wall, and your car will meet increased air resistance which will slow it down and make it unstable at high speed.
Make the car light - weight reduction is a key part of having a fast car. All fast cars both R/C and real life are made of expensive materials such as carbon fibre. It is very popular because it is very light but also very strong and rigid.
Gearing - this is one of the trickier parts of the car's setup. The car can always be geared up but you have to watch your motor and ESC temperatures carefully as they will quite possibly be working much harder than usual. Depending on the KV rating of the system you are using, you may be able to get away with gearing the car up further without issue. Lower KV motors have more torque so can take higher gearing, but will have less RPM. So it is a case of finding the best balancing act between RPM and torque for your particular car. You don’t want it to end up like this.
Toe in/out - generally, a good basher R/C car will have a small amount of toe in on the rear wheels and a small amount of toe out on the front. I will be trying this setup to begin with on my speed runs, but will be trying to switch to very little toe in or out as I get more practice as that seems to be a popular setup with the true speed cars like the Arrma Limitless.
Suspension and tyres - a stiff suspension setting is a must. Some speedrunners don’t use suspension at all. This is to reduce the movement on the car to the minimal amount. Tyres wise, foams are a must as they will not expand at the higher RPM that the wheels are exposed to.
