Managing Racecar Tires - Tire Watch

Tires are a key ingredient in motorsports and a big topic at any track across the country, whether you are sitting in the stands or behind the wheel. In fact, tires can generate an emotional response from a racer almost as fast as a comment about the promoter refusing to pay prize money.

It is important that teams learn how to manage the tires they have. This means developing a process for managing tires that fits the team's respective division.

If viewed as a process, the ability to manage tires is a skill not much different from engine building. Tires are a valuable resource that impacts performance to a level measurable with a stopwatch.

Tires are the only real interface between your car and the track. Ideally, every racer would have new tires each race, but that is not likely to happen. Even if you had new tires each race, which ones would you run? How do you tell the difference between a new tire that will help and a new tire that will hurt your performance? Is it possible that new tires could have a performance differential over the last set of tires? New doesn't necessarily imply better, although conventional wisdom says new tires are better than used tires.

Two different views of tires in the same class on two different cars. The tire is much more worn on one of the cars.

The central issue is defining or characterizing the tire. While this may sound like a simple statement, we need to specify what components or features make up the tire. Let's add some constraints to this picture. If the division you race in requires a specific tire, it may seem to simplify the preparation process, but in reality it may have gotten a bit more difficult. With everybody running the same tires, the decision point over purchase becomes a bit simpler, but the tire definition may be more difficult if you are trying to gain an edge over the competition.

That takes us back to our initial statement about defining the tire: What are we going to measure? What are the parameters that are important to us and our racing program? This is a valid question no matter if you race on dirt, asphalt, or concrete tracks.

There is no way around it-taking and recording measurements is a critical step within your racing program, and it is critical to a good tire management program. This is about more than just lap times. While important, lap times are really a resultant measurement, not a measurement that is driving performance. Some other factors are also responsible for lap times. More specifically, from a tire perspective, what are you measuring with regard to your tires? The easy answers are tire pressure and outside diameter, as these are the most prevalent measurements occurring in the pits. What else should you be measuring and tracking on a regular basis?

Which one do you think will work better? Documentation, notes, and the data to make an informed decision are needed to answer that question.

Age Of The Tire

The first thing you need to keep track of is the age of your tires-not only from the date of purchase and how long you have been using them, but from the date the tires were manufactured. Tires are no different from produce at the local supermarket in that they have a shelf life, and it is in your best interest to buy the newest tires possible.

Most tires have a unique identifier molded into the sidewalls. This number is usually coded and molded into the tire by the manufacturer to keep track of the date of manufacture and the lot codes. While these numbers are not usually made public, it is in your best interest to do a little sleuthing to get an understanding of what these codes mean. For example, some manufacturers use a very simple code that is very understandable in spite of not being completely intuitive. You may see an alphanumeric code that makes no sense to the casual observer. But a little digging may reveal that the last four numbers in the code (e.g., 4305) hold the information you need. While this may seem somewhat cryptic, it could mean the tire was manufactured in the 43rd week of 2005 or it could mean the 43rd day of 2005. While not that important if the tire is going on the family cruiser, it would be good information if you were selecting tires at the local tire shop in order to go racing.

Given the option, I would prefer the newer tires, or at least tires that were made in the same lot/week. While this is not a code system used by all tire manufacturers, I know for a fact that some manufacturers use this coding system. It is up to you, the consumer, to stay informed. If you are buying new tires and you have a choice, you should select tires that are just weeks or days old versus tires that are over a year old. Conversely, you may find that some tires made in a specific lot were faster than the same tire made in a different lot. We all know that no matter how much the tire maker may try, there is still a good deal of variation and that variation may hurt or help you. If you keep track and keep good records, you may discover an advantage. If you don't do this, then you will never know.

The disc keeps mud from filling the wheel and adding extra weight. It also keeps the valve stem from being damaged when the other cars are not playing nice. A drawback is that it makes checking tire pressure a bit more time consuming.

Keeping track of the tires based on some individual or unique identifier is a critical part of a well-executed tire management program. The date code will not work for this unless it is part of a larger number that is unique to each tire. If you cannot find a unique identifier on the tire (I have never had racing tires that did not have a unique number or symbol in each tire), then paint the number on the wheel. It is unusual to rotate tires between wheels, but if you do, make sure the number transfers with the tire from wheel to wheel.

Prior to purchasing the tires, you should use a durometer to check the hardness of the rubber. You need to be careful about this screening process, though, as the tire seller may not appreciate you going through the store's tires and testing each one for hardness. In fact, you may not even be allowed to go through the inventory. In all fairness to the tire dealer, you need to be discrete while you are doing this. The objective is understanding the tire. If you are in competition and have found that a softer tire is faster in your class, then get the softest tire you are allowed to run. If the tire is a spec tire and the entire class is running the same tire, I would strongly suggest checking and tracking tire hardness at the point of purchase and through the life of the tire. There are times when a harder tire is actually a better selection. If this is the case, you need to know which tires in your inventory are the hardest.