I understand that when the road is wet, deeper tire tread will move more water out of the way and keep you from hydroplaning. On dry pavement, does deeper tread help with traction? IE, would the same tread pattern with 1/2” tread provide more grip than 1/4” tread? If so, why?
Regular tires have tread, unlike race car tires which do not have any tread at all. Regular tires are designed with tread to keep a car stable and safe in different road conditions. Race cars use tires without tread because smooth tires provide better traction in dry conditions.
If the ground is wet, however, drivers will suddenly find themselves needing the grooved tread that siphons water away from the tires. Otherwise, water will come between the tire and road surface, causing the driver to lose traction and hydroplane. The tread patterns of a tire are designed to displace water so that the tire and the road maintain contact. If you only drive on dry, flat ground, you will be fine with a smooth-surfaced tire. But since rainy, snowy days are inevitable in most parts of the country, tires with tread are the best option for safe driving.
I was thinking the same thing - racing slicks. I read somewhere you can buy these too for the weekend track wannabe. After all, thousands of miles of tire life isn’t the priority on racetracks. Another fun fact I recall reaing is that the Formula 1 tires are also warmed, becase warm soft rubber grips the road better.
I assume things like smal pebbles and such road debris also benefit from tires having grooves to escape being trapped between tire and road. Like the problem with water, tread helps tires grip on everyday road conditions.
One thing you might notice, typically by the time treadwear becomes significant, the tire carcass has also become a bit stiffer, and the rubber itself loses some “gription”, rubber ages or loses desirable characteristics due to sunlight exposure and ozone. The process is slow and maybe not noticed over time, but by the time fresh tires are installed it is usually notably better handling, noise, and braking.
Drag slicks. You swap out your street tires on the rear of your car and put on your drag slicks. So yes to the OP, tire tread is for rain, no tread is better for dry traction.
Mickey Thompson | Drag Tires (mickeythompsontires.com)
If you want to go beyond just basic drag slicks, you get wrinkle wall slicks. Same kind of slicks with little or no tread and weak side walls.
Wrinkle wall tires are entirely smooth, wide tires used in drag racing. The sidewall wrinkles or shrinks because of the torque, allowing maximum surface contact.
This is the purpose of the burn-outs you see done before drag racers move up to the starting line. It is not just for show, it is to heat up the tires and make them sticky. It used to be called bleaching the tires but they have since gone to just using a patch of water. Wet the tires, do a burn-out, now you have hot sticky tires and are ready to drag race.
Here’s a Pirelli site on their F1 tires- if you’ll notice, they have different rubber compounds for the slicks AND different tread patterns/depths for the rain tires.
F1 tyres: details and technical data | Pirelli
So basically slicks are great on dry pavement- more contact with the pavement. But they’re awful in the rain- highly likely to hydroplane.
Most all-season tires are made to be a compromise across the board- ok in snow, ok in rain, ok in dry, but not optimized for any of the above.
It’s always fun to see the wrinkle-wall slicks expand rapidly when doing a burnout.
And some racers (NASCAR, e.g.) who race on ovals use different tires left and right! It’s a science…
In the top tiers of motorcycle racing, the tires are circuit-dependent. One side of the tire may be a different compound than the other depending on the arrangement of the turns and how that results in tire stresses.
As regular car tires age, the rubber gets thinner and thinner. AS this happens the road noise is transmitted through the steel belts buried in the tread. The road noise inside the car gets louder and louder but it happens so slowly that the driver gets used to noise. When new cushy tires are installed the car gets quieter VERY suddenly.
Slicks are better on dry pavement than rain tires in the rain, so teams are motivated to use slicks whenever possible. The interesting times during a race happen when the rain is just beginning/ending, or when only part of the track is wet. When do you give up on slicks (or when after the rain do you revert back to them)? If you choose wisely, you can go faster than your competitors for a few laps. If you choose poorly, you may hydroplane when you hit that last remaining puddle of water left on the track.
Preheating the tires helps them have decent grip for the first minute or so after leaving the pit, but it’s the ongoing cyclic strain of the tire tread and carcass during the race that provides the heat to keep the tire warm for the next XX laps until they return to the pit. Moreover, preheating doesn’t get the tires as hot as race driving does; drivers still need to take it easy when they first leave the pits until their tires have had a chance to come up to full race temp.
Rain tire tread is also made of really soft compound, since it’s going to run cool because of the wet driving conditions. As the track starts drying out after the rain, rain tires start running hot, and drivers will purposely aim for puddles to try to keep them at a safe temp. Sometimes the rain tires do get too hot and start chucking blocks of tread.
One of the features of a Tesla, where there’s no engine rumble to help hide road noise - the tires have a foam liner to help mitigate road noise. The difference with snow tires (deeper tread, no foam lining) is quite noticeable. Also road quality - i.e. rumbly old cement vs fresh asphalt - is very noticeable.