Camber also affects the size and cross-sectional loading of the contact patch. The correct camber angle compensates for the deflection of the tire sidewalls as the lateral force is applied when we turn the car. More or less camber than what would be ideal means that one side of the tire will support more load than the other and this also reduces traction.
Some tracks and sanctioning...
Some tracks and sanctioning bodies allow the use of tire treatment which softens the rubber compound. This can be a way to limit cost allowing a team to run otherwise uncompetitive hard, old tires. Other tracks outlaw tire soaking but look the other way on this issue and the teams must soak their tires in order to be competitive. Promoters should define and enforce tire rules either way.
3. Chemical makeup
The chemical makeup of the compound of the rubber will help to determine how much traction is available from a tire. A softer tire will provide more grip, but the maximum amount of traction that can be utilized over a long period of time concerns how the tire holds up to increased heat and wear. A tire that is a little harder may sometimes hold up better and be faster toward the end of the race when the tires have built up a lot of heat and are well worn after a number of laps.
4. Angle of attack
The amount of traction available from a tire can actually be enhanced simply by increasing its angle of attack relative to the direction the car is traveling, but only up to a point. From traveling straight ahead, we can turn the wheel and with each degree of angle of deviation from the direction of travel, the traction in the tire increases.
There is a point we reach where the gain is reduced and we approach the limit of the attack angle that the tire can handle. Once that point is reached, going beyond causes a sudden loss of grip and traction falls off drastically. This principle is true of all four of our tires whether they are the front or rear tires. We will provide more on this subject later.
5. Equal loading
An opposing pair of tires (tires on the same axle or at the same end of the car) will develop maximum grip when they are equally loaded. That is a generally true statement that has been made many times in the past in countless publications. Upon more careful examination of how we do things in circle track racing, there is a unique situation where that is not exactly true.
The situation is when we have a tire on one side of the car (usually the left side) that is built with a softer compound than the opposing tire whereby it may be able to develop more grip under the same loading as the opposing tire. So, increasing the vertical load on the inside tire with the goal of attaining equal loading for both tires, by whatever means, may not actually generate more traction because of the difference in grip per pound of vertical loading created by differences in compounds.
The shape of the track for both dirt and asphalt can influence the available traction in several different ways. As we apply power, we need to know a little about how the track is banked, how the banking angle is changing coming off the corners and how the radius of the turn might be changing.
A highly banked racetrack is very forgiving when it comes to the need for bite off the corners. There's so much downforce due to the banking and associated lateral forces, that many times the tires are loaded to the extent that the power generated by the motor can't break the tires loose. The tracks we are most concerned about getting off the corners are the ones that are flatter and with less surface grip.
The severity of change in banking angle of the racing surface in the portion of the track where we are initially accelerating can cause changes to the pitch angle of the chassis that works to unload one or more tires which can reduce traction. A track that goes from high banking in the turns to low banking on the straights fairly quickly can cause the left rear tire to unload quickly making the car loose. There are two ways this can happen. One is when the outside edge of the track drops in elevation and the right front tire follows the drop-off which, in-turn, lifts load off of the left rear tire causing loss of traction in that tire.
As a driver turns the steering...
As a driver turns the steering wheel, the front tires develop an angle of attack relative to the direction of travel of the car. The more the wheel is turned, the greater the angle of attack.
With increased angle of attack,...
With increased angle of attack, the front end gains traction up to a point where the angle becomes excessive and the tire gives up most of its available traction resulting in a severe push. We use this effect to overcome a tight car. A severely tight car is termed "tight-loose" and the excess steering input results in the car becoming loose past the mid-point of the turn.
Many current dirt tracks as...
Many current dirt tracks as well as some asphalt tracks that used to be dirt have developed a "D" shape. This is caused by having a wall along the grandstand side only and as the track gets raced on and graded, the back side away from the grandstands gets pushed out. This makes the radii of Turns 1 and 4 smaller and tighter than Turns 2 and 3. More steering is required for the tighter turns and in Turn 4, it's usually very difficult to get traction under power as opposed to exiting Turn 2.