To start, anytime you run your car and are determining what to do with your set-up ask yourself these questions.
1.
2.
3.
4.
5.
6.
What is the car doing in the initial second that I
turn the steering?
What does the car do entering the corner?
What does the car do exiting the corner?
How far into the corner am I using the brakes?
How soon do I get on throttle and how fast?
What does the car do throughout the corner -
entering until exit?
These questions will help you determine where to change your set-up or driving style.
Definitions:
Understeer (aka push or tight):
This is when a vehicle has the tendency to "push" toward the outer edges of a corner.
Oversteer (aka loose):
This is when the back end of the vehicle wants to lose grip and travel around the front of the vehicle.
Camber:
Caster:
Negative -
Positive -
top edge of tire leans toward the centerline
of the vehicle.
top edge of tire leans away from the centerline
of the vehicle
The angle of the front upright relative to the ground plane, should always be positive.
Toe:
Squat:
In -
Out -
leading edge of the tires point toward the centerline
of the vehicle.
leading edge of the tires point away from the
centerline of the vehicle
Same as caster only on the rear of the vehicle.
I'll explain the basic effects of changes on the above and give a few examples of situations and possible solutions.
Camber -
Adjustments to this setting determine how much contact patch the tires have relative to the ground plane. Less contact Patch will usually cause less grip though this is not always the case. Tires have an optimum operating temperature (all do). This temperature dependance makes it tricky to set up camber since a full contact patch can cause the tire to run at a lower temperature than is necessary, In this case you need more camber, On the other end you could have to much camber centering the heat on a certain part of the tire which overheats the tire causing it to slip. In this case running less camber is better. If you are running a full contact set-up and are still overheating the tire or major camber and still under heating the tire it's time to run a different tire. By taking the tire heat into account you can reduce or increase grip by increasing or reducing camber. Though this is dependant entirely on the characteristics of your tire.
Positive Camber is rarely used because it causes the outer edge of the tire to roll onto it's side which is not a good thing because you loose all traction. The only time positive camber may be used effectively is on certain oval tracks (usually less banking)
Caster -
This adjustment tends to affect the responsiveness and stability of the vehicle. The stability factor is usually eliminated in the RC cars because the steering is solid linked to the servo which centers the steering. The more caster the more the steering tends to self center creating stability, however it also causes the initial turn in to be less responsive and body roll to be greater due to the angle of the tires to the road. If you lower caster the car becomes more twitchy, less stable and has less mechanical body roll. The lower the caster angle the more the tire contacts the road when turning.
Toe -
Toe adjustments improve stability anytime they are greater or less than 0 or neutral. This is because it centralizes forces. But toe has a much more important roll in the handing of the vehicle. Toe out will cause the steering to become more responsive but due to the reduces steering angle of the outer front tire the vehicle will tend to understeer when coming out of the corner. Toe-in will cause the car to turn in a little less responsively but will allow the car to hold a tighter line coming out of the corner. Toe is an adjustment that can truly make you faster or slower because it determines when you are able to get on or off of the throttle.
Ride height -
Ride height will make minor adjustments to handling. An even ride height will do nothing to the handling of the car. Lowering the front relative to the rear will give more steering, Lowering the rear in relation to the front will give a little understeer
Shock settings-
I'll just overview the shock settings and give a little note on oil and springs. First oil does NOT determine stiffness of the vehicle, Springs do. Oils controls the springs and springs control the vehicle, oils DO NOT control the vehicle. Set the oil so that your springs can return your car to the ride height fast if you want a responsive car or so it returns slow if you want a more stable car and a little sluggish. If your car sags get harder springs, don't use spacers. If your car bounces get softer springs or run heavier oil. Try to use pre-load spacers only to determine ride height. This can make or break a set-up. 90% of the RC cars that I see are not correctly set-up in this area and that may be a generous figure. Remember the above and it will help you out.
Roll Bars-
As far Is I will get into roll bars at this moment is to say that they are secondary springs that are used only during cornering. In many cases with RC cars they are not needed unless you cannot get your car stiff enough in the corners while keeping it from bouncing down the straights. Or you are having a problem with a tire lifting off the ground. If you are having a problem with a tire lifting put a roll bar on the opposite end of the car.
Diagnosis / Solutions can be found on theexamplespage.
©1997 Penguinr/c
Originally produced for Lawrence Keys, R/C Adrenalin web site.
