aww bill you're to easy on em
into google i typed: high speed tire ratings
1st link gave me this:
Tire Selection Guide For Passenger Tires
There are a number of things to consider when purchasing tires for your personal vehicle. Specifically, these considerations can be categorized as follows:
* Tread Pattern Design- "All-Season" vs. "Touring vs. Performance"
* Treadwear Performance vs. Grip/Handling Traction Performance
* Tire Speed-Rating ("*", "T", "H", "V", "W", "Y", "Z")
* High Performance Tires
There is a tire-line to fit virtually every driver/vehicle combination and need. There is a significant amount of overlap in different tire lines to satisfy these different combinations of needs. For example, there are All-Season/ Grip/ "*" Speed-rated/ Low Price tires; Touring/ Treadwear/ "H" Speed-rated/ High Price; All-Season/ Treadwear/ "T" Speed-rated/ Medium Price tires; Performance/ Grip/ "Z" Speed-rated/ High Price tires, etc. All designed to meet customer needs. Let'* look at each of the considerations listed above in more detail.
All-Season Vs. Touring Vs. Performance
All-Season tread designs will provide good all-around traction for varying road conditions such as Wet, Snow and Ice, but still provide good Treadwear & Tire Noise characteristics. Performance tread designs have been engineered to Enhance a vehicles Handling capabilities on wet and dry roads, but usually exhibit increased Tire Noise and Lack Long Treadwear Life. Performance tread designs usually have larger tread elements to provide a stiff tread area for handling performance. Touring tread designs were designed to bridge the gap between All-Season & Performance tires. Touring tread designs combine the technology for good treadwear characteristics from All-Season tires and handling & grip associated with Performance tires. Touring tires also exhibit very good Tire Noise and Ride Comfort.
Treadwear Performance Vs. Grip/ Handling/ Traction Performance...
The treadwear-traction trade-off has been a focus in Tire Performance-Enhancement Technology for decades. Tire companies have been trying to reduce the trade-off between treadwear & traction through the development of new rubber, new tread designs, and new tire construction techniques. Basically, a tire will wear-out quickly if it is providing maximum grip to the road. This is due to the tread rubber being torn from the tire (on a microscopic level), while it is adhering to the road surface. An excellent treadwear tire minimizes the amount of rubber being removed at the road surface; thus providing long tread life, but less road gripping traction.
Tire Speed-Rating ("*","T","H","V","W","Y","Z")
A common Trade-Off for higher Speed-Rating is reduced Ride Comfort. An "*" Speed-Rated tire will give a more comfortable Ride compared to "H" Speed-Rated tire, and a "H" Speed-Rated tire will give a more comfortable Ride compared to a "Z" Speed-Rated tire. The Ride Comfort Characteristics can be attributed to the tire'* Overall Stiffness. A tire capable of running at High Speeds requires a more stiff construction, in order to provide the necessary high speed stability & durability.
Tire Speed Rating Symbols:
* 180km/h or 112mph
T 190km/h or 118mph
U 200km/h or 125mph
H 210km/h or 130mph
V 240km/h or 149mph
W(ZR) 270km/h or 168mph
Y(ZR) 300km/h or 186mph
ZR Above 300km/h or 186mph
A Z-Speed Rated tire without a Service Description means that the customer must consult the Tire Manufacturer to obtain the tire'* Maximum Speed Capability.
As with the many different levels of tread design, tire performance, and Speed-Ratings: there are many different levels of pricing within a category. For example, prices can vary from $50.00/tire to $125.00/tire depending on the brand name. When you multiply this price by 4 wheel positions, the price can become significantly high, and more difficult to justify.
High Performance Tires
High Performance tires typically have Speed-Ratings of "H" or higher; although, tire companies have developed Entry-Level performance Tires that exhibit "*" & "T" Speed-Ratings for the people that want only the "look" of Performance.
In order to maximize the most handling from a tire, the High Performance tire tread widths are wider than a typical "All-Season" and "Touring" tire. This allows Maximum Contact Area with the road surface. In this case, Wider is Definitely Better! The tread Pattern incorporates larger tread blocks for increased Stiffness. The tread compound is usually softer than a typical "All-Season" and "Touring tire, in order to provide more Dry Traction Capability. Faster Treadwear (less tread life) is generally observed in High Performance tires, because of the better Dry Traction Capability. Racing tires are an extreme example of High Performance tires; exhibiting MAXIMUM Dry Traction & Grip with a significant reduced Treadwear Life.
The stiffer construction used in High Performance tires not only Aids High-Speed Performance, but enhances tire Handling Characteristics. A High Performance tire has quick Steering Response and plenty of available Cornering Power, which makes for excellent Vehicle Handling Characteristics. Nylon Reinforcement creates a stiffer belt package, which means better Steering Response and higher Cornering Grip. Usually, the carcass plies are angled or "biased" slightly to again increase the tire'* Overall Stiffness.