Setting up a remote control car is as much a science as it is an art, the physics behind rc cars is exactly the same as the physics that governs real cars, if you know how setup changes in a race car work, you already know how to setup a remote control car.
The problem that most people have with setting up RC cars is that when you make a change in one area it always has a knock-on effect on the rest of your settings, setups are very much a balancing act
To start with I’ll concentrate on the basics of handling, over steer and under steer. The physics behind this is pretty simple, if you turn into a corner the center of gravity will move in what ever direction you were initially travelling. Your tires via friction push back with (hopefully) an equal amount of force. When your wheels lose traction and start to slide the energy that was being turned into heat in your tires gets released as inertial energy in the original direction of travel. With cars, both back and front don’t break traction equally, this creates either under steer or over steer, which is how we describe the experience the driver has under these conditions.
Under steer
Under steer is when the front of the car loses traction while the rear of the car still has grip on the tar, the effect is that the nose of the car drifts away from the direction you are turning, turning harder makes it worse, the only thing you can really do is back off the throttle and bleed off speed.
Over Steer
Over steer is the opposite of under steer, and in most cases it’s best to have a little of this. The front of the car keeps traction while the rear lets go. One of the key benefits is that you can typically corner much faster in a car that has some over steer
Over steer / Under steer Tuning tips
There are a lot of ways to tune the handling or your radio controlled car, the easiest is to adjust the front and rear shocks. While there are a lot of options with springs, different oils and all sorts we are just going to concentrate on the basics, most decent shocks have adjustments, either with spacers or bolts that let you adjust how hard or soft the shocks are.
As far as maximum and minimum stiffness goes, make sure that the bottom of your car doesn’t scrape the ground, and on the other end make sure it doesn’t bounce and leave the asphalt, apart from that you need to find the setup that matches your driving style, most people get winning setups off the internet and try to learn to drive them, mind you this is a great starting point, and most championship winners post their setup sheets
Shock Stiffness guide
Stiffen in front = increasing under steer or reducing over steer
Stiffen in rear = increasing over steer or reducing under steer
You may be wondering why one setting makes two changes, this is because it’s all about balance, you could for example setup your rc car by only every changing the rear stiffness, but you would find that when you got the perfect amount of over steer under braking the car would then be uncontrollable during the exit of the corner. It’s all about balance,
Another thing to keep in mind is that when you change the shocks you also change the roll of the car, this the the chassis of the car moving with the inertia, in effect pushing the front tires into the road during breaking and the rear during acceleration. If your shocks are too soft then the transfer might dig your front wheels in and lift the rear enough to make you car spin out, or lose steering under throttle, you have to find the right balance
More to come…