2005 TIRE BUYERS GUIDE

www.tirerack.com

The Tire Rack prides itself on being a well-stocked company with informed employees, and from what we saw during our testing at Tire Rack's South Bend, Indiana, headquarters, we can't dispute it claims. For starters, Tire Rack has a test facility where it tests all the products it sells. That means it doesn't take a manufacturer's claimed performance as fact. If a tire, wheel, or suspension package performs, Tire Rack employees know because they tested it personally.

Every team member spends roughly 80 hours a year in the classroom and testing products. Therefore, when you call to order something, the person taking your order is educated on correct fitments and knows how the product could affectyour car.

As for stock, Tire Rack has four giant warehouses across America in Indiana, Nevada, Delaware, and Louisiana - all stocking more products than you can imagine. In fact, some tire manufacturers use these warehouses as an emergency reserve. For the customer, this means the tire you want is only a phone call away. Check out the website and see for yourselves exactly what they offer, and view the forums to see what their customers have to say about each product.

The track has several combinations, but we used a figure eight layout for its combination of 90-degree bends leading to a 200-foot skidpan circle. Cones were used to provide a lane-change exercise, in addition to tightening some corners. This combination provided a variety of handling situations, as well as braking tests and g-force assessment. The track is ringed with laser beams that timethe overall lap, the time through the lane change, as well as a section of the skidpan (from which a g-force measurement could be calculated). The track is a relatively simple layout but it helps the drivers achieve consistency.

The surface is smooth and unpatched. A series of sprinklers allow the track to be doused with water, simulating typical rainfall. The surface is cambered 1 degree to the inside, as are most public roads. The idea is to recreate the sort of driving conditions you might encounter every day.

www.turnermotorsports.com

The difficulty with tire testing is driving a road course consistently for two days and being able to feel and remember the nuances of every tire, both in the wet and the dry. That kind of skill can only be found in experienced race car drivers. So that's exactly what we got. Actually, to be on the safe side, we got two.

Will Turner, owner of Turner Motorsport, and Don Salama, a TMS professional driver, volunteered for the mission. Their racing experience includes claiming the 2003 Speed World Challenge Touring Car championship, plus a string of race wins and pole positions.

Will Turner runs one of the leading independent BMW race teams in the world. He has a total of five BMWs racing in the 2005 Grand-Am Cup, Speed Touring Cup and SCCA T2 series.

Another reason we approached TMS was because TMS doesn't have any specific affiliation to a tire manufacturer. In fact, Will claims he stopped selling wheels and tires a while ago, instead referring customers to Tire Rack. The only association TMS shares with a tire company is Toyo, which supplies the spec tire for the Speed World Challenge Touring Car class and sponsors the TMS M3 in the T2 class. To ensure this allegiance doesn't affect the results, the drivers have no idea what tires are on the car when they run and when they comment on the performance.

We'd like to thank both Will and Don for taking the time to attend our event and putting in a consistent effort to make the test a success.

A tire's size is usually written as a series of numbers, for example: 225/45-17. The 225 represents the width in millimeters. The 45 is the sidewall height as a ratio of the tire's section width. In this example, the sidewall would be 45% of 225mm, or 101mm. The 17 represents the diameter of wheel in inches the tire will fit.

On the following pages we have provided some specific information about each tire in the test, and here's a brief explanation about what some of the terms mean.

Tread Depth - For the most part, the tires we tested come with 10/32" tread depth. The shallower the depth, the better dry traction it should have, although the life span may be shorter.

Tread Design - There are two designs in our group: directional and asymmetric. Directional tires have a forward-rolling direction, while asymmetric have tread blocks that must be positioned toward the outside of the vehicle. In some cases, there are directional asymmetric tires.

Tread Wear - Tread wear ratings are obtained on a government-specified course, and although the number doesn't mean much, it's useful for comparison. For example, a tire with a tread-wear rating of 200 should wear twice as well as a tire with a score of 100.

Traction - This rating scores only wet braking, and the tire can achieve AA, A, B, or C, where C is the worst. The AA rating was added in 1997 when new tires began to excel in wet-braking tests. Keep in mind, the traction rating doesn't take cornering ability into consideration.

Temperature - The temperature rating is scored as A, B, or C. The tire is scored while properly inflated and the car isn't overloaded.

Uniform Tire Quality Grade (UTQG) - The UTQG comprises the tread wear, traction and temperature ratings. The UTQG is a DOT-required test all tires must undergo to be sold for street use in the USA. The UTQG is clearly printed on the sidewall of every tire. The minimum accepted for our test was a UTQG of 140.

Load Index - This is represented by a number generally between 71 and 110. It's important to note that the load index changes based on the tire's size. For the 225/45-17 we tested, most fell between 90 and 94. A load index of 90 means the tire can support 1,323 lb, whereas a rating of 94 means it can support 1,477 lb. Generally, the smaller the tire, the lower the load index.

Speed Rating - This is achieved by running a tire on a metal drum at the correct load and speed for 10 minutes, then increasing the speed by 6.2mph. Most people view Z-rated tires as the best, but this is outdated. Z-rating means the tire is rated at a generic 149-plus mph, and many people thought there would be no need to rate a tire at a higher speed. However, new tires are rated at V (149mph), W (168mph), or Y (186mph).