Tire grooves channel and disperse the water on wet roads. If it weren't for grooves, your tires would be 'aquaplaning' on every patch of water, and not gripping the surface.
You should change tires when you look at the grooves and they are ground pretty smooth. You want grooves in your tire so that it has good traction. If you put a nickel in-between your grooves and it doesn't stick out, then your tires are still good.
So the water you drive through will be channelled through the grooves to prevent aquaplaning.
sulcus
Not all tyres have grooves. Take the "slick" tyre - it does not have grooves. It is used always in racing (as it is illegal to use on most countries roads) and only in dry weather (permitting). "Normal" tyres have grooves, as a channel to expel water from the surface of the tyre. Without these "grooves", driving in the wet would be a hair-raising experience, as the tyre would aquaplane on the water giving the driver, no grip or control. This is also the reason that most countries have a limit on the tread depth, to ensure that the channels are large enough to expel any water away from the surface of the tyre.
The grooves or "tining" placed on concrete bridge decks (surfaces) are created for for automobile tire traction when it rains and to help direct the water runoff. Typically the grooves are created in the transverse direction across the direction of automobile travel. More recently longitudinal grooves have gained favor because there is less noise generated when tires follow longitudinal grooves when compared to more noise generated when tires cross transverse grooves.
The Uranus moon with V-shaped grooves covering over one third of its surface is Miranda. These grooves are believed to be caused by tectonic processes on the moon's surface.
The differences are the size and the purpose. Regular tires are made to grip the asphalt, and also fitted with grooves to push water away, keeping it from hydroplaning. The off road tires are thicker, and the grooves are much deeper, giving it the ability to have good traction in the dirt and rocks.
Frank Seiberling
Depends on the track mainly but cutting proper grooves in your tires is a good start
get a penny, and place it upside down (with Lincoln's head facing down) in one of the grooves. if you can see the top of the head its time to get new tires.
in case of f1 cars the road surface is even and it does not consists of stones and pebbles and also f1 has to maintain a high grip with road surface but in case of ordinary tyres they r to be driven in rough areas n also surfaces which r uneven so to adjust itself and balance vehicle at variable speeds in such uneven surface . hence many times v see small atones suck into the grooves