Tire Inspection, Tech, Maintenance - Rolling Along

Getting good results means more than mounting a tire and racing off. Knowing the tires are the only link that comes between the track and your perfectly set-up race car, we at Stock Car Racing talked to a few of the tire gurus to compile some helpful information.

Tire Storage

First, keep your tires away from direct heat sources and direct sunlight. Torches, welders, and heaters will deteriorate the consistency of the tire. Tires are best stored in a dark, well-ventilated, temperature-controlled area ranging from 65 to 75 degrees.

Second, remove all loads/weight from the tires. This prevents flat spots from forming if the tire is left in one place too long.

Third, to maintain consistent sizing, tires should be stored inflated at race pressures. Bias-constructed tires can shrink with age creating a sizing change if stored uninflated.

Finally, do not use chemical tire cleaners. Chemicals can be harmful to sidewall rubber and can expedite sidewall cracking and discoloration.

Tire Pressure Gauge

This is the most important tire tool. You should always have a good quality gauge and a back up gauge. Check the accuracy of your gauge regularly.

Pyrometer Check

Tony Freund, Goodyear Tire’s lead engineer for NASCAR tire development, suggests using a pot of boiling water to check the accuracy of a probe-type pyrometer. Because water boils at 212 degrees, sticking the probe of your pyrometer into the water will indicate whether the probe is providing a correct reading.

Keeping moisture out

“Moisture can create problems with uneven tire pressure. The air inside the tire will expand when it gets hot and a tire with a high amount of moisture in the air will heat up at a different rate,” Freund says. “This can cause all four tires to have unequal pressures and running temperatures, and heat and cool at different rates. If you’re not using nitrogen, a simple way to help reduce the moisture inside the tire is to purge the air after the tire has been mounted and then refill it. This will help get rid of the moisture/high humidity from the soapy lubricant used during the mounting of the tire.”

Breaking In

When using the tire for the first time, a good way to help extend its life is to break it in. For the first few laps, take it easy. Let the tire heat up and then cool back down. This, in a way, tempers the tire and will help extend its life.

“Driver’s habits can take a toll on the life of the tires. When coming into a turn, the driver needs to turn the race car without a ratcheting motion. Turning into the curves smoothly greatly improves tire life,” Todd Steen, manager of racing activities for BFGoodrich, says. “Setting your race car too loose will make the rear tires wear quicker and setting the race car too tight will wear the fronts. Getting the car set up properly significantly extends tire life.”

Craig Cowan, Hoosier’s dirt tire product manager, and driver Scott Bloomquist gave us some guidelines for grooving and “siping” tires. Like asphalt racers, dirt racers have to pick the right tire compound, and even more important, often have to alter the design of a tread pattern that works with the conditions at a particular track.

As the roughness of a track increases, so does the need for grooves. Unless the track surface is very smooth, some sort of grooving is likely to be necessary to be fast. When you groove a tire more, it makes the tread surface much more flexible. It can then shape itself to match the surface of the track to provide the maximum amount of bite as possible.

When sniping and grooving your tires, you have to consider the abrasion of the track, how wet or dry the track is, and if the track contains rocks or other debris that will tear up the tire. These conditions must be considered when deciding what kind of groove to use, how deep to cut and how many grooves can be cut out without causing premature tire wear. Also, grooving can help control the amount of heat the tire can dissipate.

Grooving and Wear

When a groove or sipe is cut into a tire, it accelerates wear. This means balancing the benefits of grooving with the increased wear is a delicate trick. Sipes are added to tires to prevent the tread surface from glazing over, becoming slick, and keeping the tire’s surface wearing evenly throughout the race.

Learning how to determine the amount of wear you can expect from a track will help you choose the right compound tire, groove pattern, and depth. The object is to maintain the highest level of traction throughout the race without wearing the tread off too soon.

Grooving Widths

When racing on tracks with a small amount of abrasion, the edges on the tire can increase traction considerably. Wider grooves create a cleaner, more prominent edge to the racing surface. Narrow grooves may not have enough distance between edges to allow them to work properly.

On a rocky or highly abrasive track, a smaller amount of wide grooves stand up to these harsher conditions better.

Shapes of the Grooves

Three basic shapes are used in grooving:

Square: Square grooves are the same width throughout its entire depth. Square grooves can be used the same way, but the extra width could provide enough leverage for an abrasive track to tear the tire.

V Grooves: These start out wide at the top and taper to nothing at the bottom. The V groove is often used when more tread contact with the track is needed later in the race. As the tire wears, the grooves become smaller or disappear completely.

Sipes: These are thin slits cut by installing the blade upside down in the holder and using the separate ends of the blade to cut slices in the tire. Siping is usually done to make the tread more pliable. It does not produce the edges that square or V grooves do. Siping also helps the tread maintain a more consistent wear that helps keep the tire working uniformly.

Keeping Records

Good record keeping is the best way to improve your tire performance and longevity. Reading and logging notes about your tires after each race and applying that information will help you learn what type of tire preparation works best for racing in similar situations.