Tires are the limiting factor to any suspension upgrades that increase the handling capabilities of the car since the contact patch, compound, tread pattern, and casing design combine to provide the connection of the vehicle to the pavement. For a car like mine that gets used on road tracks we use a wide, soft compound tire, that has big tread blocks. It is a type of tire designed for track days on full size road courses that is still barely streetable and carries a DOT # so it's legal. These are road track tires which require a certain amount of heat in them to function at their best so the first lap or two on track brings the tires up to temperature. Tires designed for auto-X are different and do not require the warm up that road track tires do. Our first couple laps is like a drag car warming up slicks to get them sticky.
A wide tire gives a bigger footprint and with the larger contact patch comes increased traction. At 285 mm front and 295mm rear these tires are almost a foot wide, about double what the stock factory tires were! Double the width, double the grip = double the FUN!!
These Yokohamas have a treadwear rating of 60 which is very low and indicates a soft compound so you wouldn't expect to get a lot of street miles out of them. I don't care about longevity. Chances are, the tires will start to dry and loose their grip in a 3-4 years before I wear them out anyway. At least thats what happened with my last set and 6 years is max tire life. Yokohama makes these AO48 tires in 2 different types. One for lightweight cars and one for heavier cars like mine. The difference in construction helps keep the tires in the optimum heat range for the rubber compound to provide the most grip. If I ran the tires designed for the lightweight cars on mine, the tires would overheat, and become "greasy" by the middle of a track session. Tire life would be greatly reduced.
The tread design on these tires is designed to channel water in rain if necessary (road course track days do not stop for rain) and keep the tire DOT legal. The large blocks provide a very stable connection to the pavement. The taller and narrower the tread blocks are, the more the blocks can move (squirm) and on road tracks cars with tires like that are limited by the tires.
The rounded casing design of these tires provides a good contact patch and smooth transition from full braking to cornering loads and again when rolling back into the throttle through the turn with a predictable feel. Tires like these don't squeal around corners so the driver has to pay more attention to how the car "feels" through the steering wheel and seat of the pants.
http://www.yokohamatire.com/tires/advan_a048.aspx
