One of the most important technical aspects, when discussing dirt track racing, would definitely be the tires. It is the first thing that hits the track and can really dictate your performance.
We use only Hoosier Racing Tires and there are numerous compounds, sizes and tire rules across the country. I run the World of Outlaws (WoO) Craftsman Late Model Series most of the year, and we have a few different rules.
When we go to the Northeast we use the Hoosier 1300 most of the time. The next area would the Midwest, and we usually use the LM tire compounds, which are called LM20. The last area would be the South and that is where we typically utilize the Hoosier 1350.
The area dictates the rules because we need to have the best tire on the car, so that we can put the best race on for the fans. The Northeast likes the 1300 compound because track surfaces up there tend to have a little slime to them. The softer 1300 compound and the chemicals that are inside the tire adapt to slime better.
A 1350 in the South is better because it has a different chemical in it that reacts better to the abrasive tracks.
Tire preparation before you get to the track is extremely important and can really make or break your performance. Tires need to be kept inside and out of the extreme heat or cold, when you’re not using them during the week. They also need to be properly cleaned during the week so that you can inspect and decide if you need a new one or if it needs re-siped or grooved again.
Sipes are lines in the rubber that allow the tire to move back and forth so that the tire can work itself like it needs. Grooves are deep and wide lines across the tire that helps filter the dirt out, and it also will better the performance.
Lastly, is the actual preparation of the tire. You as a driver or crew chief need to inspect the tires every week and decide on how you’re going to get the tires ready for the next week. The characteristics of the tracks that you’ll be racing are what dictate the way you groove or sipe a tire.
A slimy track would require more sipes and grooves, so that it can properly work since those tracks are typically easier on tires. More sipes and grooves allow the tire to work better.
A good example would be Lernerville Speedway in Sarver, Pennsylvania. This track is in the Northeast and is usually very easy on tires and sometimes can be slimy. For this track we would need to have our tires grooved more than most places. We can also get more aggressive with the depth and number of our sipes.
The more sipes in the tire means it can work and move more while you’re racing. This typically gives you a little more grip and can make the tire work faster before it gets heat built up in it.
You would not want to have a tire that is not siped or grooved because in the slime it might not work as good or would take a few laps for it to come to life. At that point you could lose a lot of valuable spots at the start of the race.
An example in the South would be Dixie Speedway in Woodstock, Georgia. The characteristic of this track is that it’s very hard on tires and shows a lot of abrasion and tire temps throughout the night.
You wouldn’t want to sipe your tires as deep or groove as much because it can cause the tire to wear out much quicker. This would cause you to fade at the end of the race or at the end of a long green flag run.
The track doesn’t require as much sipe and grooving because the track supplies a lot of the grip needed to make your car perform. When you travel to a very abrasive track – like Dixie Speedway – you need to worry about tire life and how long it can last throughout a long race.
Lernerville is the opposite because it usually has no abrasion and will not wear a tire out.
A guy, who hits the track at Dixie Speedway with a very aggressively prepared set of tires, can run good on lap 5 compared to a guy with not as aggressively prepared set of tires. However, from lap 40 until the checkered the guy with tires not siped as deep will probably be a lot faster. He will be faster and still have rubber left on the tire.
In addition, it won’t be moving around as much since he didn’t have it siped as deep. The deeper sipe combination will probably be worn out or chunked out before the end of the race because of the abrasion that the track supplies.
Hopefully this article has helped provide a better understanding of prepping tires for different rules and track types.