For starters, smooth tires do not equate certain death. The main purpose the tread pattern on a tire serves is to provide a route for water to go through.What this means is that when a tire with a tread pattern rolls over a wet patch of road, it dislplaces and removes the water from the road’s surface, allowing it to have cleaner contact with the road and ultimately more grip under wet conditions. Tread patterns can also increase grip in low grip environments, as is the case with off road tires, where the grooves are bigger and the knobs on the tires sharper and taller, so that mud and dirt can be displaced much like water but also because the treads can dig into soft and loose ground and provide mechanical grip.
In a controlled racing environment however, grip is essential, and the larger the contact patch of the tire the more grip you have, mainly due to the ability to moderate heat better. There’s actually a lot that plays into the overall grip of a tire and not just size but I don’t want to get into it and digress. However it is worth noting that even in racing use, when the weather is bad and the track is wet, grooved tires are also used.
The important thing here is that using a smooth tire on a wet road can lead to what is called hydroplaning, where the tire has no way to remove water from the road surface other than pushing it to the side as it rolls over the road, much like the bow wave of a ship. However this creates the possibility that water is trapped momentarily between the tire and the road surface, which reduces grip significantly and the driver has very little control of the direction of the car. For this reason in most jurisdictions it’s illegal to use “slick” tires on public roads and road legal tires have to have at least some amount of grooves to remove water. What that means is that if you see a smooth tire on a vehicle out on the road, it’s either someone using slicks illegally (unlikely, they’re very expensive and have very low mileage capabilities), or it’s a tire that used to have grooves but has worn down to the point of being smooth, in which case it’s very dangerous since it’s old and worn through, has no ability to remove water, has lost its elasticity over time so it’s harder as well as having worn through the usable part of the tire which means that the internal liners may start coming into contact with the road and that provides very little grip and also the tire may just burst after a point.
**TL;DR** Smooth tires that used to be grooved are certain death. Slick tires are not certain death.
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