Chassis Setup is the most important factor in having a fast Dirt Oval car. However, there is no magic
setup that will work on every car and every track condition for every driver. One driver may a like a car
that steers very aggressively, while another may like to drive a smooth, slower reacting car. The most
important thing for each driver to find is BALANCE! Balance means that the front end and rear end of
the car have equal traction, and gives the driver a comfortable feel when driving the car at speed.
Typically, if your car turns into the corner well, and then the rear end slides out, you are experiencing a
“loose” race car, and you will need to add traction to the rear end to improve the balance of your
chassis. Likewise, if your car seems to lack steering entering the corner, and you have to slow down too
much to get around the corner, you are experiencing a “tight” race car. Finding and maintaining balance
is the key to a consistently fast car on any racing surface, and your goal should be to find a balanced
setup, more so than a fast setup. A fast setup may yield that one lightning fast lap, but a balanced setup
will be easier to driver for 4 minutes, often yielding in a faster overall run.
Knowing What to Adjust
Most racing chassis come with a “standard” or “Kit” setup. Most companies spend countless hours in
development and testing to come up with their baseline setup, which is why I always suggest that you
start with the standard/kit setup. The standard setup is typically the setup that they felt yielded a very
comfortable handling chassis on many types of track surfaces. Think of this as your home. If you get
“lost” with your tuning and find that you have lost the balance of your car, go back “home” to the
baseline setup and start over!
The purpose of this tuning is to help you enjoy racing dirt oval, and help you understand the many
chassis adjustments available to you to change your car to suit both track conditions and your driving
capabilities. Please note that there are many ways to setup a car. I like to say that “there a thousand
ways to bake a cake, you simply need to find the recipe that you like.” Not all chassis adjustments will
have the same exact effect in every situation; however, following the info provided in this guide should
help you achieve a general understanding of chassis setup. Most of these chassis adjustments will apply
to any track surface, however, in some extreme track conditions; an adjustment may not have the
desired effect on handling. My goal is to help you to better understand which chassis adjustments you
should make, what the adjustment should do, and why the adjustment does what it does. Once you
understand this, then, hopefully, you will better understand when to make which adjustment, to achieve
the best chassis setup possible for the given conditions.
Suspension Theory 101:
Your suspension has one main purpose; to control the amount of Weight Transfer to each corner of the
chassis, which in turn changes the amount of traction that tire can achieve. Every component of the
suspension plays a part in controlling weight transfer. Every adjustment you make to the chassis changes
the amount of weight transfer created, and where it transfers to, changing the overall balance of the
car. Chassis setup is the art of controlling weight transfer.
Generally speaking, a “tight car” is an easy to drive car, and a “loose car” is much harder to control. My
personal motto in chassis setup is to “Hook up the rear, then make her steer.” Easy to drive is better for
all racers. Even the most talented racers go faster with an easier to drive chassis.
To best understand what the chassis is doing, we need to go over the basic handling characteristics:
- On-power Steering: On-Power Steering refers to how the car steers when throttle is applied.
- Off-Power Steering: Off-Power Steering refers to how the car steers at neutral throttle or no throttle
applied. - Push: When a car is cornering but the front tires are sliding more than the rear. A car with a “push”
does not have enough steering. Although a car that “pushes” is easier to drive, a car that pushes is
slower in the turns than a car that is slightly “Loose”. (Also known as “Tight” or “Understeer”) - Loose: When the rear of the car slides more than the front. A car that is loose has too much steering. A
“Loose” car tends to rotate more easily; however, a car that is too loose is harder to control and may
spin out easily. (Also known as “Free” or “Oversteer”)
Next, we need to break the track up into 4 segments to best analyze what part of the track we need to
work on. - Corner Entry: This is the first part of the turn where you begin turning in. This is where the front of the
car dips towards the track and the rear of the car lifts up a little, causing weight to transfer to the front
tires, giving more steering. (Off-Power Steering) - Mid Corner: This is where you maintain balance of the car with your throttle and steering input. This is
where the chassis leans over as far as it is going to lean. (Neutral Throttle) - Corner Exit: This is the part of the turn where you begin to apply throttle. As you apply throttle, the
front end rises up and the rear end squats down, transferring more weight to the rear tires causing the
car to have more rear traction. (On-Power Steering) - Straights: The straight part of the track after corner exit, typically where you are full throttle, and likely
backing out of the throttle prior to corner entry.
If you can tell what your chassis is doing in each segment of the track, you can then determine what
adjustments will best suit your needs. Understanding what your chassis is doing, and where it is doing it
is half of the battle. This is often the hardest thing for new racers to “get a feel for”
Chassis Tuning 101
Matt Murphy’s Dirt Oval Chassis Tuning Guide