Performance Tires - Tire Anatomy 101

The Inside Story On Performance Tires

Shane Reichardt Jun 1, 2000 0 Comment(s)
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BFGoodrich also offers a DOT-legal ultra-high- performance tire in their g-Force T/A KD. The treadwear is right in the middle of the scale with a 200.

Performance Street Tires
You want a number of different things from a set of street tires. For instance, too stiff a sidewall may translate into a harsh ride. Conversely, a soft sidewall will cause the car to be less responsive and soft. A hard tire compound may last a long time but may also be louder. Too soft a compound will cause the tire to wear quickly (and it may collect rocks and debris and toss them at your nice paint job).

The "series" tire you run can have nearly the same effect as a soft sidewall. A low-profile tire has less of a sidewall to cushion the ride. This is great for most high-performance machines, but may leave your wheels open to damage should you hit a rock or pothole (little sidewall to absorb the impact).

One of the new features incorporated into many tires is a sidewall stiffener, which is a hard filler placed above the bead. By filling this void the sidewall is stiffened, making for a more responsive ride.

Another feature found on some tires is a rim protector. This ingenious feature is little more than an extra rubber shoulder near the edge of the wheel. Its purpose is to protect the wheel from damage should you accidentally get a bit too close to a curb. It's a simple feature that's not found on all tires, but one you should consider the next time you purchase tires.

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Drag Tires
One of the biggest differences between a performance street tire and a tire intended for the strip is the sidewall. On the street, a performance tire should have a fairly stiff sidewall. This allows the tire to be more responsive. Less sidewall flex will allow the car to respond faster when you crank the wheel.

With most drag tires, you will want at least a small amount of sidewall softness. This allows the tires to wrinkle. Wrinkling allows the shock of acceleration to be taken up by the tires rather than by the suspension (though ideally your suspension should be doing most of the work). The goal is to find a tire with just the right amount of sidewall softness to work with your suspension combination.

Some drag racers with a well-setup suspension may not want too soft a sidewall. The advantage of a stiff sidewall is less tire wrap or sidewall distortion, thus better reaction at launch. This is good for heavy cars, or cars with a suspension, that can absorb the initial launch. If you were running a fixed suspension car like a dragster or an altered, you would need a softer-sidewall tire to absorb the launch.

There are two ways to stiffen the sidewall. One is to run tubes to help support the sidewall. Another is to match the tread width with the wheel width. Going 1 inch wider on the wheel width will help stiffen thesidewall. One thing to remember is that too stiff a sidewall will cause the tires to lose traction on launch, because all of the torque is immediately transferred to the contact patch which, responds to the shock by unleashing cool clouds of tire smoke.

DOT legal drag tires are a godsend. Now those with streetable vehicles can drive their car to the track and not need to change to sticky tires when they get there. We wouldn't recommend driving to and from work on them, but to and from the track is no problem. One important thing to remember with these tires is that each manufacturer has specific instructions on the proper burnout. Though a John Force long, smoky display might get the crowd on their feet, it probably won't do much for your performance.

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This photo shows the BFGoodrich g-Force T/A KDW--a performance tire intended for wet and dry driving conditions.

Aspect Ratio: The relationship of a tire's height to its width, expressed as a number that represents the nominal percent the tire's height is of its width.

Bead: A round hoop of steel wires that is shaped to fit the rim around which the tire's body plies are wrapped and holds the tire onto the rim.

Belt: A rubber-coated layer of cords that is located between the body plies and the tread rubber. Cords may be made from steel, fiberglass, rayon, nylon, polyester, or other fabrics.

Bias-Ply Tire: A pneumatic tire in which the plies are laid at alternate angles less than 90 degrees to the center line of the tread. Plies usually run at angles of about 30-40 degrees relative to the tire center line in a criss-cross fashion.

Carcass: The tire body beneath the tread and sidewalls; also called the casing.

Cold Inflation Pressure: The amount of air pressure in a tire, measured at ambient temperature before a tire has built up heat from driving.

Compound: The hardness or softness of the rubber used in tire construction.

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As you can see, water is pushed aside to allow the tread to make maximum contact with the pavement.

Cord: The strands of material forming the body plies or belt plies of the tire. Cords may be made from aramid, fiberglass, rayon, nylon, polyester or steel.

DOT Markings: A code molded into the sidewall of a tire signifying that the tire complies with U.S. Department of Transportation safety standards. The DOT code includes an alphanumeric designator that can also identify the tire's manufacturer, production plant, date of production, and brand.

Footprint: That portion of the tread in contact with the road.

High-Performance Tire: In the tire industry, those tires with speed ratings of S or greater and aspect ratios of 70 or less.

Highway Tires: Also called summer tires; designed for wet-and-dry weather driving, but not for use on snow and ice.

Hydroplaning: A skimming effect caused by tires losing contact with a surface covered with water when traveling at speed.

Innerliner: The innermost layer of a tubeless tire. The innerliner prevents air from permeating through the tire.

Overall Diameter: The outside diameter of the inflated tire, without any load.

Overall Width: The distance between the outside of the two sidewalls, including lettering and designs.

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Tread Width: The width of a tire's tread.




Toyo Tires
Chicago, IL 60680
Yokohama Tires
Fullerton, CA 92631-5106


Wheels Tires
The inside story on performance tires
Shane Reichardt Jun 1, 2000


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