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.
Most of the time, teams running on asphalt tracks use the same mandated tire for the entire event and only adjust air pressure and stagger. It is an entirely different and more complex story for dirt racing. Not only are there several tread and compound designs to choose from, but also the teams alter the tread pattern by cutting out blocks of rubber and siping (making small cuts in the rubber) to change the grip characteristics as well as the cooling properties of the tire.
A dirt tire on a wet tacky surface needs large grooves and no small crevices in order to shed the wet material quickly. Once the track is packed and starts the transition toward slick, more edges are needed to get a grip on the track surface. The siping cuts help cool the tire by releasing the heat generated from sliding across the slick surface.
The art is knowing when to make changes along with knowing what changes are needed at a given point in time. On dirt, the car is not able to utilize the positive properties of a good setup if the tires are not right. It may take several seasons of hard learning to be able to accurately guess the needs of your dirt tires.
Dalton Zehr prepares for practice...
Dalton Zehr prepares for practice in the Circle Track Modified car as his dad, Marty, looks on. Although Dalton got up to speed quickly, he admits he needs more seat time before being capable of winning.
There is no need to underestimate asphalt driving by calling it a day at the park. It's somewhat more difficult than it looks on TV or from the grandstands. There is a difference between a good asphalt driver and one who needs more seat time or a different inheritance of chromosome. The asphalt driver seeks a more consistent and smooth driving style while he or she learns how to pass and defend a position. The less the driver has to turn the steering wheel, the better. That isn't true in dirt track racing.
Dirt competitors also strive for smoothness, but they contend with the car at all kinds of attitudes along the way. That entails lots of steering input while your posterior tells you where to steer and how far. Running a few inches off your competitor's door is a little more difficult at speed and at a 45-degree angle to the direction of travel.
A common predicament among several new-to-dirt drivers is knowing where straight-ahead is with the steering wheel. Most entries involve steering first to the left and then right, and then left again coming up off the corner. If the car gets too far around at mid-turn, the driver's hands can get crossed up and he or she loses the sense of where the wheels are straight-ahead.
Chris had to tape the steering wheel at the top at dead straight-ahead to have a point of reference. Dalton, having experienced the same problem, now puts his hands in the 10 and 2 "clock" positions instead of the usual 10 and 4 he was used to on asphalt.
Despite the complexities of dirt track racing, lots of teams and fans love to compete and watch. It's no wonder dirt racing represents over 60 percent of the short track circle track racing that goes on in America. If you haven't tried it, you would be doing yourself a huge favor by accelerating your learning curve.