Street tires vs. Racing tires: what’s the difference? – Jalopnik

Although NASCAR stands for the National Association for Stock Car Auto Racing, the cars we see on the high banks of Daytona couldn’t be further from stock. The races of yesteryear may have a little more similarity between what happens on the track and what’s in the showroom, but NASCAR, like the rest of modern motorsports, has a much more clearly defined line between road car and race car.

For better or worse, there’s plenty of technological distinction between what you see on the track and what’s on the street. Although much of the technology developed in Formula 1 has found its way to our daily drivers, we don’t need a new engine every 2,400 kilometers, like Verstappen and Norris. We don’t know which versions of Honda’s new prelude will hit the road, but the 650 hp rear-wheel drive variant from the Super GT is unlikely to be included. Our steering wheels, while a huge upgrade from those of decades ago, thankfully won’t set us back $100,000 for replacement like Formula 1.

For commuting rather than competition, many parts of your car are made to unique specifications, and your tires are no exception. Although brands like Pirelli, Goodyear and Firestone can be found on both race cars and road cars, what these brands make for the track couldn’t be more different than what you have for the street.

Let’s start with the biggest difference, which is also the most noticeable at first glance. While your road tires have channels and treads, the slicks you see on race cars are, well, slick. There are no steps built into the smooth (and sometimes shiny) surface. Why is it that racing tires don’t need tread, but our everyday cars do?

The simple answer is water. On wet surfaces, the grooves in road tires are intended to direct water through the tire and prevent aquaplaning. On the other hand, racing slicks are made for dry running only and are all rubber on the surface to get the largest contact patch possible.

But if you’ve seen apparently ‘dry races’ scared by sudden rain, you know how bad it can be on slicks in the rain. Without any way to channel the water, you’re constantly sliding across a damp surface. Take a ride with Marco Andretti through the streets of Detroit and you’ll see how scary it can be:

Of course, if it rains on a race weekend, almost every series will have a wet weather compound ready, with the same grooves as on your road car to help drivers deal with the wet. Formula 1 even has semi-smooth “intermediates”. Those green-colored tires are perfect for that “crossover” point, when it’s not dry enough for full slicks, but doesn’t come down enough to warrant the blue-colored wet tires.

In dry conditions, control windows are the key to separating slicks from streets. Because slicks are only intended for use on a race track, they are designed to provide the most grip at certain pressures and temperatures. This is why tire blankets are often used in some racing series to get warmth in them before going out. However, your racing tires are intended for maximum grip at any speed, at any temperature and – as we said with the grooves – in all conditions. Unlike slicks, you don’t have to reach a certain speed or temperature to get maximum grip.

The pressure between slicks and streets also varies enormously. Street tires typically have a pressure between 32 and 45 psi, but for Slicks the pressure is only about 26 psi. That’s because of how volatile slicks are to temperatures. From a stop to driving at highway speeds, your everyday tires can gain an extra 3 or 4 psi as they warm up. For slicks, that pressure gain can range from 8 to 12 psi.

Unsurprisingly, these slicks can also get quite hotter than the tires on your street car. You can still comfortably touch your tires after a ride, as they wouldn’t be much over 90 degrees Fahrenheit. However, after a full-speed stint, racing slicks can easily reach over 220 degrees Fahrenheit. Suddenly it makes sense why pit crews now wear gloves.

While slicks would be great for lapping around the local track, they would be miserable during the nine-to-five drive. Not only would you have to constantly weave to maintain pressure and temperature in the tires, but any rain or wetness along the way will cause things to go sideways. Another feature we haven’t talked about yet is the stiffness of the sidewalls. To handle the high demands of performance driving, racing tires are often stiffer, making bumpy commutes all the more uncomfortable.

Plus, it wouldn’t make the most financial sense. Because slicks have all their eggs in the speed basket, their compound is often a rubber that is much softer than what you would have in your street car. While it is faster, the trade-off is longevity, as these slicks barely reach a fraction of how long your racing tires can last. Most street tires can easily cover tens of thousands of kilometers, but even the most difficult compounds in Formula 1 do not reach 120.

That doesn’t reflect the lives of all slicks. Some drivers have found that harder compounds used for club racing can easily last more than 10 sessions on a track before performance degrades noticeably. Still, that’s only a fraction of how long you can drive most street tires before you get to the wires.