First off, what are R-comps? They are tires designed for Racing, that’s what the R is for. But that’s a pretty vague definition as lots of tires can be used for racing. Usually, R-comps have very little tread. Some may be completely slick, while others have a couple grooves, and others have tread patterns with big blocks. The fewer grooves and blocks, the more they are designed for racing on dry pavement.
Why do racing tires have fewer grooves or blocks? Heat mostly. As the rubber squirms around it generates heat. Tires with deeper/more grooves squirm more and thus generate more heat. Too much heat will eventually kill a tire. On a race track, tires can take a lot more abuse than on the street because one is often braking and cornering at the tire’s limits. So there’s one really good reason to use R-comps, they are designed to take the heat.
R-comps generate more grip on a smooth surface than other kinds of tires. Softer tires generally have more grip than harder tires, so it’s no surprise that R-comps are very soft. Unfortunately, soft compounds wear out quickly. They also have two other important properties: they are relatively quiet when sliding and peak grip occurs over a narrow range of slip angle.
If you’re in a race, you should use R-comps because tires are the easiest way to make your car go faster. However, if you’re training, your goal is to become a better driver, you need training tires. What makes a good training tire?
- Audible feedback. Squealing rubber is really useful as a measurement of how much grip you have. It’s like the free, less distracting, and more useful version of an Apex PRO.
- Low grip. Tires with less grip slide more. Your main goal in training is tuning your ability to dynamically optimize the balance of your vehicle.
- Less stress. Having a lower traction limit means less wear and tear on you and your vehicle.
- Safety. Driving at lower speeds is safer.
- Broad slip angle. Harder tires have a broader slip angle response. This will allow you to explore the nuances of traction over a larger range of steering angles.
If you want to become an advanced driver, you need to learn how to drive a sliding vehicle. This is why the Kenny Roberts motorcycle school is run on dirt and why the Skip Barber school uses all-season tires on their Formula Fords. Harder tires slide more easily and recover more easily. If you have the confidence to slide your car around track at low grip, you can learn to do the same at high grip. However, if you start with high grip, you will probably end up fearing loss of control. People who have gone down this path end up saying stupid shit like “it’s too cold for my R-comps” or “I don’t like it when my tires are greasy” or “I don’t like driving in the rain”. Seriously, those statements are like a neon sign above your head saying “I don’t understand driving”.
So why don’t people drive hard tires on track? Apparently because they know more about driving than the Skip Barber School. Surely not. I think for many drivers, it’s about ego. They don’t want to go slower. They want to get around the track faster than other people in the HPDE session. That kind of attitude doesn’t make you a better driver.
For others it’s about fear. They don’t want to drive a sliding car because they might damage their car or get kicked out of the event for going off track. While a certain level of caution is very wise, you’ll never hear a swimming coach say “always wear a life vest”. Swimming is a life-saving skill. But you can’t learn to swim on your own if you don’t practice swimming on your own. Similarly, you can’t learn the life-saving skill of driving a sliding car unless you practice driving a sliding car.
So what tires are good for training? It depends on how much power your car makes and how much it weighs. On a light, low-powered car like a Miata, you can get away with all-season tires. I’ve used $40 Douglas tires, for example. What if you drive a Porsche, Corvette, or something like that? Well, those aren’t really training vehicles. If you can afford to buy, insure, and track a car like that, you can afford a dedicated training car.