Tire Setup - Legal Traction Control

We can never get enough traction related to forward bite in our racecars. The traction control in this case is making the tires stick whilewe are under power off the turns and down the straightaway. There hasbeen a lot of talk over the past few years about illegal tractioncontrol being used in circle track racing. We know it is being used andmay have won some races, but there may be better ways to legally goabout developing more traction under power. Many legal teams have beenable to run faster than the ones using illegal means to help keep theirtires from spinning.

Traction-enhancing technology has grown. We have collectively learnedabout what the tires want and somewhat how to give those tires theopportunity to maintain grip with the racing surface as much as the lawsof physics will allow. Let's face it. There are limits to everything inthis physical world, so we go in search of finding the ultimate limit.We try to learn to recognize when we get to that limit so we can stoplooking lest we go backwards.

The principle of stopping when you're ahead is true in developing a goodhandling package. It remains true when developing the best tractionpackage. The word "package" is an important one, because we might beusing several different approaches at the same time to enhance traction.They rarely interfere with each other and each one adds a little to thepackage. Collectively, they can add up to a marked improvement inavailable traction while under power.

In this series, we will take a look at the various areas of influencethat affect available traction and how we can maximize how our carreacts to those influences. Some are almost the same for dirt orasphalt, and some of what we discuss is very different and will betalked about separately.

Tires

Tires are the ultimate connection between the car and the racingsurface. That basic principle is not a new one, but a concept that hasalways been at the forefront when trying to understand ways to increasehandling performance in a race car. It is again at the very top of thelist when we discuss traction under power.

There are five elements that influence the amount of traction that a setof dirt or asphalt tires, the rears in this case, will develop:

1. Vertical Loading--Increasing the amount of vertical loading(weight) on a tire increases the available traction, but in a nonlinearway. As we increase loading on a tire, it will gain traction, but not inexact multiples. If a tire has "X" amount of traction with 400 pounds onit, the traction will be less than double as we apply 800 pounds ofloading to it. The amount of traction will be less than 2 times X.

2. Contact Patch--The size and cross-sectional loading of thecontact patch helps determine how much traction we will have for aparticular tire. An added area related to the contact patch and tractioninvolves grooving and siping dirt tires and will be discussed later on.

Reducing the air pressure will usually increase the size of the tirecontact patch. That would seem to enhance traction, but excessively lowor high pressures may reduce the loading on portions of the tire so thatthe total loading of the tire is reduced and we end up with lessavailable traction for that tire. There is an optimum operating airpressure for each tire that will offer maximum contact patch area andequal loading across the width of the patch.