Even Scott Bloomquist, in...
Even Scott Bloomquist, in the No. 0 car, considered racing on asphalt a while back, and some in the sport thought he would have been a good pavement racer. Notice his more straight-ahead driving line. Photo by Todd Ridgeway
1 Start out with a setup that performs under tight conditions. That would involve running a stiffer right-front (RF) spring, a stiffer right-rear (RR) spring, a higher Panhard/J-bar, having the weight lower in the car, more left-side weight, less rear steer, and less bite (referred to as crossweight in asphalt racing). Keep these settings until the track packs down and starts to lose moisture and grip.
The cars that are running laps before you go out will be going sideways on entry and mid-turn and will lose grip on exit under acceleration. Always observe the attitude of the cars that run the track just prior to your going out.
2 As the track starts to lose some grip and smooth out, begin to soften the RR spring, drop the J-bar a little, move weight to the right and up a little, and consider softening the RF spring's rate.
It's not time to get too radical with those changes, and we should develop a series of changes in four stages. This should adequately cover early practice, qualifying, heat races, and the main event.
3 After the heat races have run, the track crew may water the surface again. But since it is packed tight at this point, the water does not penetrate as well and any grip that may come with the water quickly goes away. The surface is usually slick when the feature begins.
Depending on the particular track (this is where experience with each different track comes in handy), it will go to hard and black-slick with moderate grip, or very dry and sandy-slick with very little grip. If you have followed the progression of the grip of the track, then you probably have qualified well and will run well in the heat races and the main event.
Air pressure and stagger are...
Air pressure and stagger are the only adjustments allowed for asphalt tires. That isn't the case with dirt. Multiple compounds, an array of tread designs, and team-generated altering make for a lot of combinations available to the dirt racers.
There is a vast difference between the design of the chassis for the asphalt car and that of the dirt car in the Late Model touring divisions. There are few chassis adjustments on an asphalt car compared to numerous adjustments on a dirt car. Here is a list of critical adjustments that can be made to each type of car.
Asphalt Chassis Adjustments:1 Springs (4): Usually not changed once the correct rates are found.
2 Shocks (4): Usually not changed once the correct settings are found.
3 Panhard/J-bar: Height and angle not changed throughout an event if the car is well balanced.
4 Weight distribution: Crossweight only in small increments.
5 Antidive and antisquat: Set at the shop.
6 Sway bar preload: Small changes to fine-tune the setup.
Dirt Chassis Adjustments:1 Spring rates: Up to six springs, including the lift arm and pull bar-changed often.
2 Spring placement: Movement to front or rear of the rear axle.
3 Spring attachment: Clamped or not, it's changed often.
4 The four corner shocks: Adjustable for rebound and compression and changed often.
5 Lift bar/pull bar shocks: One or two are changed or reset often for rebound and compression.
6 Panhard/J-bar: Height and angles are critical-adjusted often.
7 Weight distribution: Bite as well as physically moving weight in the car-changed often.
8 Rear trailing arm angle changes occur often.
There are more chassis tuning areas for dirt cars, and each one can and should be changed often to meet the changing conditions of the track surface. If you calculate the number of combinations, the dirt car becomes very complicated and difficult to handle.
The run-to-run adjustments for dirt include weight changes, rear steer changes, spring changes (four corners and lift arm/pull bar), spring mounting position, J-bar height and angle, stagger, tire compound, and tread design. That's a lot for anyone, and novice dirt trackers spend a lot of time confused.