Tire Care & Safety

Geestone has always been an advocate of tire safety. However, there are some situations where a tire failure can't be avoided, but by taking some simple, time-efficient safety precautions, drivers can avoid most flat tires. Tire technology has made some remarkable advancements in the last decade, but to be as safe as possible, drivers should regularly examine their tires before getting on the road. For more information on how you can safeguard yourself and your vehicle, please refer to the Rubber Manufacturers Association.
Another way to safeguard yourself and your tires is to register your tires. Everytime you purchase our tires, request a Department of Transportation (D.O.T.) card from your dealer. By completing this card, your are ensuring that we can reach you in the event of a recall.

Match Mounting

Mounting Procedures

For the proper mounting of Geestone tires, be sure to observe some basic precautions:

• Wheel is securely seated on the hub face.
• All lugs have proper torque.
• There is no buildup of dirt between the hub and wheel.
• The wheel is not bent.
• Both tire beads are securely seated on the rim.

Custom or Alloy Wheels

While custom or alloy wheels require an increased level of care over steel wheels, it is vitally important that each customer receives the highest level of service. There are several key points to note when mounting Geestone tires. Following these basic precautions not only yields consistent results, but satisfied customers—and that translates into return business and new referrals.

Avoid scratching or bending alloy wheels during installation

These wheels are manufactured with extremely soft metals with a greater sensitivity to scratching and distortion under pressure. Modern tire machines apply equal pressure to both top and bottom beads with no pressure on the wheel itself. A pad on the base of the mounting machine protects chrome-plated, painted or machined wheels from scratches and damage.

During the mounting process, proper lubrication is a must

Lubricate both top and bottom beads with an approved tire lubricant. If the beads do not seat at 40 psi, break the entire assembly down and re-lubricate the bead areas.

Observe match-mounting procedures

Proper tire and wheel assembly balancing is important from a vehicle safety standpoint. In high-speed driving, improperly balanced tire/wheel assemblies will cause a vehicle to lose stability and not operate in a safe and comfortable manner. Improperly balanced tire/wheel assemblies also cause abnormal treadwear patterns.
To facilitate proper balancing, Geestone places red and yellow marks on the sidewalls of its tires to enable the best possible match-mounting of the tire/wheel assembly. There are two methods of match-mounting Geestone tires to wheel assemblies using these red or yellow marks:

• Uniformity (red mark)
• Weight (yellow mark)

Warning: Improper mounting, underinflation, overloading or tire damage may result in tire failure, which may lead to serious injury. Tire and rim sizes must correspond for proper fit and application. Never exceed 40 psi to seat beads. Warning: Tire changing can be dangerous, and should be done only by trained persons using proper tools and procedures established by the Rubber Manufacturers Association. Failure to comply with proper procedures may result in incorrect positioning of the tire, tube or wheel assembly, causing the assembly to burst with explosive force sufficient to cause serious physical injury or death. Never mount or use damaged tires, tubes or wheel assemblies.

Uniformity Method

When performing uniformity match-mounting, the red mark on the tire, indicating the point of maximum radial force variation, should be aligned with the wheel assembly's point of minimum radial run-out, which is generally indicated by a colored dot or a notch somewhere on the wheel assembly (consult manufacturer for details). Radial force variation is the fluctuation in the force that appears in the rotating axis of a tire when a specific load is applied and the tire rotated at a specific speed. It is necessary to minimize radial force variation to ensure trouble-free installation and operation. Not all wheel assemblies indicate the point of minimum radial run-out, rendering uniformity match-mounting sometimes impossible. If the point of minimum radial run-out is not indicated on a wheel assembly, the weight method of match-mounting should be used instead.

Weight Method

When performing weight match-mounting, the yellow mark on the tire, indicating the point of lightest weight, should be aligned with the valve stem on the wheel assembly, which represents the heaviest weight point of the wheel assembly. After match-mounting by either of the above methods, the tire/wheel assembly can be balanced.

Balancing

The technical definition of balance is the uniform distribution of mass about an axis of rotation, where the center of gravity is in the same location as the center of rotation. A balanced tire is one where mass of the tire—when mounted on its wheel and the car's axle—is uniformly distributed around the axle (its center of rotation). Balanced tires can spell the difference between a positive and negative driving experience. Drivers of high performance vehicles will be more sensitive to imbalance problems, but no driver is happy with an annoying vibration.

An out-of-balance tire and wheel assembly:

• Degrades ride quality and driver comfort.
• Shortens the life of tires, bearings, shock absorbers and other suspension components. Vibration is the most noticeable effect of imbalance.
• It is dependent on vehicle speed.
• It often first becomes apparent between 40 and 45 mph and increases in magnitude with greater speeds.

Sources of Imbalance

Two sources of imbalance occur in tires: heavy or light spots in the tire and radial or lateral run-out. Imbalance also can be caused by:

• Variations within the wheel, such as thickness and welds.
• Rotor and axle imbalances.

Heavy or Light Spot Imbalance

There are two types of imbalance caused by heavy or light spots: static and dynamic.

• Static imbalance: Occurs when there is a heavy or light spot in the tire so that the tire won't roll evenly and the tire/wheel assembly undergoes an up-and-down movement.
• Dynamic imbalance: Occurs when there is unequal weight on both sides of the tire/wheel assembly's circumferential centerline. The tire/wheel assembly has a side-to-side movement.

Heavy or Light Spot Balancing

Achieved either statically or dynamically, depending on the type of imbalance that has occurred.

• Static balance: Achieved with a bubble balancer but does not correct for dynamic imbalance.
• Dynamic balance: Achieved with a spin balancer where the tire/wheel assembly is balanced both statically and dynamically.

Radial or Lateral Run-out Imbalance

This results from poor bead seating on the rim or the placement of components. Poor bead seating is usually the result of improper mounting or the use of improperly made wheels. A small degree of this imbalance is acceptable, but too great a run-out causes vibration and excessive tire wear.

• Radial Run-out: An "out-of-round" situation where vibrations are produced as the wheel spindle moves up and down.
• Lateral Run-out: A side-to-side or wobbling movement of the tire and wheel. It is less common than radial run-out. Sensitivity of a vehicle to vibration from radial run-out is four to eight times that of wobble from lateral run-out.

Run-out Balancing

Depends on whether it is radial or lateral run-out.

• Radial run-out balancing: Achieved by rotating the wheel and tire assembly two stud positions on the hub, or by rotating the tire 180¡ on the wheel. If run-out is still over specification, check wheel run-out and mark the low point. Rotate to match the high point of the assembly run-out with the wheel low point. If the assembly run-out is still too high and the wheel is within specification, replace the tire.
• Lateral run-out: Achieved by using a run-out gauge to check both the tire and wheel. Chalk-mark the highest point of run-out on both the wheel and tire. Replace whichever (wheel, tire, or both) is out of specification.

Alignment

For improved overall performance and extended tire tread life under various driving conditions and speeds, it is imperative that the tires be in proper alignment with the vehicle. Poor or improper alignment occurs when the suspension and steering systems are out of adjustment.
Several factors may be involved with poor alignment. Be aware that customers tend to replace tires rather than correct the real problem—alignment. The result can be a dissatisfied customer who switches from one tire manufacturer to the next with the same result and eventually goes elsewhere to buy new tires.
For most vehicles, poor alignment results in excessive and/or uneven tire wear. Improper alignment can reduce a tire's life by more than 70%.

Improper Alignment and Correction

Poor or improper alignment typically results in a variety of abnormal treadwear patterns that are "readable." These clues often point to one or more sources of the problem that can be measured and corrected. But before taking any alignment measurements, check the following:

• Proper inflation of each tire: Pressure over or under recommended levels will affect some alignment measurements.
• Ride height: Ride height is the distance between the vehicle's frame and the road. Because all alignment specifications are relationships between various suspension components, ride height becomes the reference point for all alignment measurements. Therefore, proper alignment is not possible if ride height is higher or lower than factory ride height specifications.

Alignment Measures

Wheelbase

Refers to the distance between the front and rear axles measured at the hub centers. This distance should be equal on both sides of the car. If not, some suspension components are worn, bent or damaged.

Tracking

Relates to the distance of each wheel to the vehicle's centerline. Each wheel should be equidistant from this centerline so that, as the vehicle moves straight ahead, wheel tracks are parallel to the vehicle's centerline (e.g., the axle should not be cocked).

Caster

To determine caster, first draw an imaginary line through the upper and lower ball joints. The angle made by this line (the steering axis) with another imaginary line drawn perpendicular to the ground (the centerline) is the caster. If the angle between the steering axis and centerline is toward the front of the car, caster is negative. If toward the rear of the car, caster is positive. Measured in degrees, caster plays a large role in determining both steering feel and high-speed stability. The goal of proper caster alignment is to achieve optimal balance between low-speed steering effort and high-speed stability. An increasingly positive caster enhances high-speed stability, but increases low-speed steering effort. An increasingly negative aster decreases low-speed steering effort and high-speed stability. For cars with power steering, an increase in low-speed steering effort increases the rate of wear in the power steering system. With most suspension designs, there is a trade-off between caster and camber angles at the extreme limits.

Camber

Viewed from in front of the vehicle, camber describes tilt of the tire from vertical. A tire has negative camber when its top inclines toward the vehicle. Positive camber occurs when its top tilts away from the vehicle. Camber is measured in degrees, and varies by car model and year. A wheel's camber angle should be adjusted to maximize a tire's contact with the road's surface under given loaded cornering conditions. Because a tire's camber changes slightly as its suspension moves during travel, the static angle at which the camber is set will depend on driving habits. If a driving style entails hard cornering, outside tires (heavily loaded) will need to have a statically set negative camber. If driving is on highways where tires are mainly subjected to lightly loaded cornering conditions, the static camber setting should be zero or slightly positive. Camber plays a large role in determining both the overall handling feel of a vehicle and how a tire wears across its treadface. A tire wears most at the point(s) where the majority of the vehicle's load rests. A properly set camber maximizes a tire's contact patch, leading to even wear. Excessive negative or positive camber has an adverse effect on treadlife by causing premature outer or inner shoulder wear.

Toe

If you were able to view the front tires of a vehicle from above the car, you would expect them to look exactly parallel to each other. In fact, they rarely are. The difference in distance between the front edge of the tires and the rear edge is called toe. Toe describes how close to parallel the two tires are, and whether they are toed-in (closer at the front of the tire) or toed-out (closer at the rear of the tire). The goal of toe is to provide proper tire wear through various driving conditions. The amount of toe your suspension is set to varies by the drive layout of your vehicle, driving preference, and car's handling characteristics. On a rear-wheel-driven car, acceleration forces on the tire tend to push the front tires back slightly in the wheel well. Static toe-in will result in a zero-toe situation at speed. For a front-wheel-driven vehicle, the front wheels will pull themselves forward in the wheel wells under acceleration. This happens because as the (driven) front wheels claw for traction, hey pull themselves forward, dragging the rest of the car along. For this situation, static toe-out will result in a zero-toe condition at speed. Assuming that the rest of the suspension is correctly aligned and maintained, and the tires properly inflated, toe-in will result in additional understeer for the car. In a corner the inside front tire will turn at less of an angle than the outside tire. Additionally, excessive toe-in will result in premature tire wear through feathering, and increased fuel consumption. Conversely, toe-out will result in additional oversteer for the vehicle. This occurs as the inside front tire turns at a greater angle than the outside tire. Thus, in a corner, the inside tire is trying to turn even more than the heavily-loaded outside tire. Excessive toe-out will also result in premature tire wear due to feathering, and increased fuel consumption.