That’s your show. If you can’t race on the track, you’ve got nothing.
– Don Kazarian
The most complicated, least understood, but most complained about subject in dirt track racing is the racing surface itself. Very few racers and race fans think about the effort that goes into preparing a track’s soil for a night of racing. On the other hand, race track promoters make race track preparation the single biggest concern for each race night. We sought out a couple of dirt race track specialists to get the real dirt on dirt.
“That’s your show,” says Perris Auto Speedway Promoter Don Kazarian. “If you can’t race on the track, you’ve got nothing.”
Southern New Mexico Speedway’s Dean Nesbit agrees, “Fans want to see racing. To have good racing, the track has to support multiple racing lines.”
A good racetrack is one that allows racing with a lot of passing. There are dry slick tracks and tacky-heavy tracks that are racy. How to get to that point depends on several factors. Track layout, soil type, weather patterns and the type of cars racing are all major considerations in preparing a track’s surface for racing.
Establishing a Base
Kazarian had the opportunity that few promoters have had; he started from scratch with the track as it was being designed, “We started with a base of native soil and compacted it thoroughly. We had more Caterpillar equipment in here than most building construction sites.”
Establishing a high compaction rate for the track’s base is imperative in order to achieve consistency in the track’s surface layer. Compaction of soil is simply compressing the grains of soil to a tight layer by displacing air from between the soil grains. A little moisture can act as a lubricant for the grains of soil to compress tightly together.
“Once you have a solid base, you need to leave it alone,” says Nesbit. “Resist the urge to plow or cut the track too deeply. Once you get the base hard-packed, you only have to worry about the top few inches, which makes it easier to produce a consistent track surface.”
Duplicating a Legendary Track Surface
Perris Auto Speedway promoter Don Kazarian explained how his track ended up with the current racing surface: “After our first couple of attempts at finding the right dirt for racing, someone said we should use the same soil that Ascot Park used. We found out that they got their soil from a cemetery, and there was no way we were going to get the 30,000 yards of material that we needed. So we took a soil sample and had it analyzed.
We called the boys at the US Geological Survey to find out where we could find soil with this same make-up. As it turned out, there was a location 35 miles to the south where the same type of soil existed. We approached the land owner and managed to work out a deal for the soil we needed.”
Soil Is the Key
Not all soil is the same. Kazarian learned early that clay content is not always the best factor to determine which soil to use. “In 1996 when we went to lay our first top layer, we knew a clay surface was what we wanted. We hired a soil scientist that helped us pick a clay soil from a local plant. The soil had 75% clay content and I’ll be honest, it was a disaster. Halfway through the night it got so dusty that the fans couldn’t see the back straightaway.”
Quickly choosing the second type of clay soil that the plant had to offer, Kazarian replaced the top layer with 30,000 yards of the new soil. “We battled that new layer for four months with the same problems that we had with the initial soil type.”
Eventually, Kazarian got soil samples from several different tracks, including the legendary Ascot park, and paid for the samples to analyzed and classified by soils geologists. Finding the common soil class that provided good racing surfaces at top tracks was a start. Finding a source for the soil was a different matter.
“We ended up calling the US Geological Survey to ask where we could find the soil make-up that we had identified,” Kazarian says. “As it turned out, the exact type of soil we were looking for existed just 35 miles to the south of our tracks location.”
The Best Recipe
“There is no universal recipe that works for every track, every season, every time of day or every type of racing,” says Nesbit. “We have soil with a pretty good amount of clay but being located in Southern New Mexico, we are right in the middle of a desert. Winds blow sand across the track and we end up with a sandy-clay surface.”
To combat issues like an abrasive sandy track, drivers tend to use harder compound tires at tracks where these conditions exist. Nesbit explains, “A lot of sand in the soil can act like sandpaper to the tires and the track may rubber up. That’s another issue that has to be dealt with.”
For Kazarian, the track surface needs a certain amount of aggregate in the soil for bonding and moisture retention. “A good track surface will have a high aggregate level. Somewhere around 25% to 30% is a pretty good percentage of aggregate to work with.”
According to Nesbit, clay has its own inherent tendencies, “Clay acts like a sponge. It absorbs water and expands. Then when it dries out, the surface develops cracks that can pose a problem in preparation. Too much clay is as bad as too little.”
Nesbit claims that the main goal in track preparation is stability, “Weekly racers want to see a consistent track.” Most of the time they don’t think about what goes into creating that consistent racing surface, but they do judge the track surface based on what was there last week. If I see one racer starting to dominate because he has the right chassis set-up for the track surface, I might throw them a curveball and change things up a little.”
It’s a lot of experience and 90% gut instinct.
– Don Kazarian
Kazarian agrees, “Controlling the amount of traction in the racing surface comes down to controlling the moisture content. Everything that we do, from racing class line ups to how many hot laps we run, is designed to keep the track in good shape for racing.”
One thing is certain about the dirt in dirt tracks; there are so many variables that it would take a full encyclopedia to cover it all. “It takes years of experience of find the balance and nuances of maintaining a race track surface,” says Kazarian. “I started in ’96 with no real understanding of how to prep the dirt. Now there are very few nights that I get surprised. It’s a lot of experience and 90% gut instinct now.”
Controlling the Variables
There’s no real way to control the moisture in the track, because there are so many variables. Being mere mortals (yes, track promoters are still mortals, regardless of how God-like they tell you they are), there is no way to control the humidity, rainfall, sun or wind. A good track man will read the signs and compensate for the conditions.
“I live on the weather channel,” says Kazarian. “Over the years I’ve paid attention to where the sun’s path crosses the track at different seasons and what happens when the winds change directions. Each of these conditions affect the track in different ways.”
Nesbit watches the dirt and takes mental notes on how the dirt is reacting to the conditions. “I also keep a close eye on the weather conditions. But paying attention to the top couple of inches of the dirt will tell me most of what I need to know.”
Sun and wind evaporates the moisture, rainfall adds additional moisture content to the soil. Promoters adjust by controlling the only element that they can, which is the amount of water they put on the track. “Too much water causes problems, especially with high powered sprint cars,” states Kazarian. “If you have a track with too much water deeper in the track, sprint car tires will dig at dirt until the track gets rutted up. Too little water causes a dry-slick or one line racing surface, which can become dusty and very unfriendly to fans watching the racing.”
Not only do the promoters have to pay attention to the weather conditions, the type of race cars featured during an event becomes an issue. “Late Models cause a track to dry out faster because of all the turbulence created under the car,” says Kazarian. “You also have to consider the tires in each division. Street stocks tires can dig in and fluff up the track where the sprint cars use tires that tend to rubber up or polish up parts of the track. We typically tailor our race classes’ line up to what the track needs.”
Kazarian acknowledges, “We have it pretty good at Perris Auto Speedway. We have equipment that many other tracks don’t have the luxury of having.”
The top of any track’s list of equipment is a road grader. “The grader is essential in knocking down the peaks and filling in the ruts to get the track’s surface smooth,” says Nesbit. “It’s one of the first things we do weekly to prep the track. Right after washing the rubber off the track and fluffing up the surface a little, we will knock the high spots down to smooth out the peaks and valleys.”
“We also use a sheep’s foot roller and a tractor pulled soil rake to help work the soil,” says Kazarian. “The sheep’s foot does more than pack the soil tightly. It actually makes a very good soil mixing tool allowing the water to penetrate into the soil deeper. The rake will wake up a track that has turned into a single line track.”
The soil rake stirs up the top couple of inches of soil, breaking any glaze and allowing moisture to percolate back to the top, or it can open the soil to the sunlight which can help dry out a saturated track.
Whatever equipment a track has, it’s important to start prepping for the next race as soon as possible. “Many racers think that track prep is only performed just prior to racing,” says Nesbit. “We start getting our track back in shape as soon as racing is over for the night. The sooner you start working the track, the easier it will be to maintain a consistent racing surface.”
While much of the equipment used in track preparation is the same as road construction, “Road work and race track prep are very different,” states Kazarian.
What to Look For
Racers may not need to understand all the intricacies of race track preparation, there are a few items to keep in mind when checking track conditions.
- If the air is hot and humid, plan on the surface drying out some.
- A cooler humid temperature will help keep moisture in the surface.
- Pick up a little dirt between your fingers and squeeze it. If it falls apart easily plan on the surface being slick at the end of the night.
- If the soil seems to hold up fairly well, you can plan on getting good traction.
- Check the track’s soil throughout the evening and stay ahead of the changing conditions.