Slick tires, used on circuits and intended for competition, must never be used on public roads. They present more disadvantages and dangers than real advantages on the road. The development of manufacturers is such that current road tires are already better than certain racing tires from only 5 years ago.
So why is using slicks such a bad idea? All MotoGP riders use them to win races, after all. That must mean they're seizing like crazy, right? They are expensive but they are necessary for driving quickly, right? And since they grip so tightly, that means they also make driving a lot safer, right?
But before continuing, a quick definition: what are slick tires? The short answer is: tires that are exclusively intended for racing. They are called slicks because they have no grooves on the carcass, in order to present an uninterrupted surface called a footprint on the road surface. This equals more grip.
But there are serious caveats why they should not be used on public roads. Failure to comply with these conditions will sooner or later lead to undesirable situations.
Temperature
Slick tires only work properly over a restricted temperature range
This is the most obvious factor. All types of tires perform at their optimum level within a certain heat range. However, slicks work best around 100 degrees for the front and 120 degrees for the rear. This is relatively hot, and hotter than the boiling point of water at sea level.
That's why racing teams wrap them in tire warmer blankets before a race. The covers are set at 90 degrees Celsius, for at least an hour.
Do you understand why professional runners usually set their fastest race times after the third lap or in the middle of the race? Why do MotoGP riders keep heating their tires on the formation lap while the tires are coming out of the covers?
The answer is temperature and how to keep it within that range. When leaving, even if the covers are removed at the last moment, the motorcycles remain stationary enough for them to have time to cool down. So the tire temperature at the start of a race is already incorrect.
Second, driving on public roads, even without traffic, won't raise the temperature quickly enough.
Third, even if the rider is able to heat the tires up to their optimal operating temperature, traffic, road and weather conditions will slow him down at some point, forcing the tires to cool below their working temperatures. .
Heating cycles
A tire that has undergone a heating cycle
You'll see it after riding hard on the roads or track - that blue/purple stripe on the edges of the tires. The bands indicate that the tires are releasing their oil after a warm-up cycle. This is natural because tires contain oil as part of their compounds.
A warm-up cycle means the process of cooling tires from their operating temperature to ambient temperature. Depending on the brand and the compound, a racing tire withstands very few heating cycles (between 8 and 10).
This means that even if you could run them at the ideal temperature, you would only be able to use them for 4 daily trips. That would make a hell of a tire budget...
It doesn't matter if the tires still have 99% of their rubber thickness, these tires are already unusable after a certain number of cycles. In other words, they lose grip.
Cold shearing
Cold shearing causes this type of wear
On the edges of a slick tire that comes off the track, there are small pieces of rubber that look like what you get when you use a rubber eraser on paper.
Riders usually associate this with a grippy tire, but these were rather wide and deep.
This is called cold shearing. As the name suggests, the surface is torn off due to use below operating temperature. Instead of rolling on the track, the tire sinks. The tire can even throw pieces of rubber in extreme cases.
Weather situation
Jack Miller had dared to mount the slicks and not his opponents, who had all rushed into the pits. This earned us this epic image!
That's the other obvious reason, besides the temperature. Slick tires are designed to operate only in one weather condition: dry weather. The grooves in a tire help wick water between the contact patch and the road surface and provide grip. Conversely, the absence of grooves will cause the tire to hydroplane.
To be fair, slicks can work on wet roads (provided they're at the right temperature) but not on top of a film of water.
This is the whole game of the technical team and the challenge of achieving a good time on a drying track: use the slicks or the rains?
Suspension settings
Using different tires requires different suspension settings. However, it is much less crucial to achieve this with road tires than with slicks. On the other hand, using typical road settings for slicks may not create enough deformation to warm them up. Again, relying on track settings for the road would result in an uncomfortable ride.
To try to win… what?
Not everyone is capable of this kind of feat on a closed road!
To experience slicks at their optimal level, there's no better place than on the track. Here the tires will warm up faster even without covers. You just have to be flexible on the first laps, then put on the gas to chase the time when the bike, the tires and the rider are hot!
The stock tires are already impressive!
Currently, production tires perform at levels we couldn't even dream of two decades ago. Sports touring tires stick to the road in the dry and in the rain.
This allows you to save money and use standard tires for everyday life. They heat up quickly, can last more heat cycles, work in all conditions, are comfortable, and are certainly cheaper and easier to maintain than slicks.
We're not criticizing you for using slicks, but think about what we've written and go back to street tires. You will be amazed at what you could do with them.
