Air Pressure

Air pressure for your new Kumho tire should be set in accordance with the vehicle manufacturer's specification if it's the same as the size originally equipped on your vehicle. The vehicle manufacturer's recommendation can usually be found in the owner's manual, on the door jamb or in the glove compartment. Contact the vehicle dealer for more specific information about your car. Vehicle placard inflation would be the minimum recommended inflation by Kumho Tire.

The importance of maintaining the proper air pressure cannot be overstated. Under-inflation can lead to excessive heat build-up and structural stress and can cause a tire to fail. Over-inflation can cause uneven tire wear in the center portion of the tread pattern and can also lead to vehicle handling problems. Do not check tire pressure after the vehicle has been operated because tires heat up, causing the air pressure to rise. Allow them to cool and then perform your check. Check your spare tire as well. The proper air pressure for a spare is often different from the tires mounted on your vehicle. The proper air pressure for your spare should also be listed in your owner's manual, door jamb or glove compartment. Use a quality air gauge when checking the pressure (digital gauges are the most reliable) or have a professional service technician do the work for you. Maintaining proper air pressure will also contribute to better fuel efficiency. So check, be safe and save!

Tire Rotation

Ideally, tires should be rotated every 3,000 to 5,000 miles. When this is done consistently, the tires are more likely to maintain good handling and traction and deliver maximum tread life. However, it's important to remember that tire rotation alone cannot guard against rapid or uneven wear if your vehicle has faulty mechanical parts or improper tire inflation pressure.

Rotation Patterns Explained

Forward Cross - The most commonly used rotation pattern, designed primarily for front wheel drive vehicles - which most cars have.

Rearward Cross - For rear wheel and 4-wheel drive vehicles.

X-Cross - Also for rear wheel and 4-wheel drive vehicles - but can also be used as an alternative to the Forward Cross method for front wheel drive vehicles.

Front-to-Rear & Rear-to-Front - Primarily used for performance vehicles equipped with directional tires of the same size.

Side-To-Side - Primarily used for vehicles equipped with non-directional tires of different sizes.

What about the spare tire? - If your spare tire is of the same size as the four tires in service, you should include that spare in your rotation pattern. Follow the manufacturer's recommended rotation sequence, or introduce the spare into the rotation pattern in the right rear position.

Temporary - use spares cannot be included in your tire rotation.

Tread wear Performance vs. Grip/Handling/Traction Performance

The tread wear/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 tread wear and traction through the development of new rubber compounds, new tread designs and new tire construction techniques. Basically, a tire will wear out quickly if it's providing maximum grip to the road. This is due to the tread rubber being torn from the tire (on a microscopic level), while it adheres to the road surface. An excellent tread wear 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 (S, T, H, V, W, Y, Z)

A common trade-off for higher speed-rating is reduced ride comfort. An S speed-rated tire will give a more comfortable ride compared to an H speed-rated tire - and an 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's overall stiffness. A tire capable of running at high speeds requires a more stiff construction in order to provide the necessary high speed stability and durability.

Tire Speed Ratings

Z speed-rated tires originally reflected the highest tire speed rating - i.e., in excess of 149 mph. When new cars were developed that could exceed this speed, the automotive industry added the W and Y ratings. While a Z speed-rating still often appears, such as 215/50ZR16 91W, the Z in the size signifies a maximum speed capability in excess of 149 mph; the W in the service description indicates the tire's 168 mph maximum speed. When the Y speed-rating in a service description is enclosed in parentheses, such as 285/35ZR19 (99Y), the top speed of the tire has been tested in excess of 186 mph, indicated by the service description as shown below:

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 S and T speed-ratings for the people who want only the "look" of performance. In order to maximize handling from a tire, 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 tread wear (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 and grip, with significantly reduced tread wear 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" to increase the tire's overall stiffness.