Wheels and Tires: Description and Operation
Tires and Wheels DescriptionTire and Wheel Balancing
There are two types of tire and wheel balancing: static and dynamic.
Static balance is the equal distribution of weight around the wheel. Assemblies that are statically unbalanced cause a bouncing action called wheel tramp. This condition may eventually cause uneven tire wear.
Dynamic balance is the equal distribution of weight on each side of the centerline so that when the assembly spins there is no tendency for it to move from side to side. Assemblies that are dynamically unbalanced may cause wheel shimmy.
General Balance Precautions
Remove all deposits of foreign material from the inside of the wheel.
WARNING: Remove stones from the tread in order to avoid operator injury during spin balancing.
Inspect the tire for any damage. Balance the tire according to the equipment manufacturer's recommendations.
Wheel Weights
If more than 85 grams (3.0 ounces) are needed to static balance the wheel, split the wheel weights as equally as possible between the inboard and the outboard flanges. Balancing the assemblies with factory alloy wheels requires the use of special nylon-coated, clip on wheel weights. These weights are designed to fit over the thicker rim flange of the alloy wheel. Install these weights with a plastic-tipped hammer. Adhesive wheel weights are also available. Use the following procedure to install adhesive wheel weight kits
Adhesive Wheel Weight Installation
1. Clean the wheel by sanding it to bare alloy where the wheel weight will be installed.
2. Use a clean cloth or paper towel saturated with a mixture of half isopropyl alcohol and half water to wipe the place where the wheel weight will be installed.
3. Dry the area with hot air. The surface of the wheel should be warm to the touch.
4. Warm the adhesive backing on the wheel weights to room temperature.
5. Remove the tape from the back of the weights. Do not touch the adhesive surface.
6. Apply the wheel weight and press it on with hand pressure.
7. Secure the wheel weight with a 70 - 110 N (16 - 25 lbs.) force applied with a roller.
Tire Chain Usage
Due to limited tire-to-body clearance on certain vehicles, recommendations for tire chain use are published in the Owner's Manual. When tire chains need to be used, that vehicles require SAE Class "S" tire chains. These may also be designated as 1100 Series, type PL tire chains. These chains are specifically designed to limit the "fly off" effect which occurs when the wheel rotates. Be sure that only fine-link chains are used which do not add more than 15 mm (0.590 inch), including the lock, to the tread surface and the inner sides of the tires. Manufacturers of tire chains have a specific chain size for each tire size to ensure a proper fit when the chain is installed. Be sure to purchase the correct chains for the tires on which they are to be used. Use rubber adjusters to take up any slack or clearance in loose chains.
Use of chains may adversely affect vehicle handling.
When tire chains are installed, follow these precautions:
^ Adjust speed to road conditions.
^ Avoid sharp turns.
^ Avoid locked-wheel braking.
To prevent chain damage to the vehicle, install the chains on the front tires as tightly as possible. Tighten them again after driving 0.4 to 0.8 kilometer (0.3 to 0.5 mile). The use of chains on the rear tires is not recommended because they may contact the vehicle and possibly damage it. If chains must be used on the rear tires, be sure there is sufficient clearance between the chains and the body. Do not exceed 70 km/h (45 mph) or the chain manufacturer's speed limit, if lower. Avoid large bumps, potholes, severe turns and any other maneuvers which could cause the tires to bounce. Follow any other instructions of the chain manufacturer which do not disagree with the above instructions.
Replacement Tires
A tire performance criteria (TPC) specification number is molded in the sidewall near the tire size of all original equipment tires. This specification number assures that the tire meets performance standards for traction, endurance, dimensions, noise, handling and rolling resistance. Usually a specific TPC number is assigned to each tire size.
CAUTION: Do not mix different types of tires on the same vehicle such as radial, bias and bias-belted tires except in emergencies, because vehicle handling may be seriously affected and may result in loss of control.
Use only replacement tires with the same size, load range, and construction as the original. The use of any other tire size or construction type may seriously affect ride, handling, speedometer/odometer calibration, vehicle ground clearance, and tire clearance to the body and the chassis. This does not apply to the spare tire furnished with the vehicle.
It is recommended that new tires be installed in pairs on the same axle.
If it is necessary to replace only one tire, pair it with the tire having the most tread to equalize the braking action.
Although they may appear different in tread design, tires built by different manufacturers with identical TPC specifications may be used on the same vehicle.
All Season Tires
Most vehicles are now equipped with steel-belted all season radial tires as standard equipment. These tires qualify as snow tires, with a 37 percent higher average rating for snow traction than the non-all season radial tires previously used. Other performance areas, such as wet traction, rolling resistance, tread life, and air retention, have also been improved. This was done by improvements in both tread design and tread compounds. These tires are identified by an "M + S" molded in the tire sidewall following the size number. The suffix "MS" is also molded in the sidewall after the TPC specification number. The optional handling tires used on some vehicles are not all season tires. These will not have the "MS" marking after the tire size or the TPC specification number.
Passenger Metric Sized Tires
This vehicle uses Passenger (P) metric sized tires. P-metric tires are available in two load ranges: standard load (35 psi maximum) and extra load (41 psi maximum). Most passenger vehicle tires are standard load.
Most P-metric tire sizes do not have exact corresponding alphanumeric tire sizes. For example, a P175/70R13 is not exactly equal in size and load-carrying capacity to an FR70-13. For this reason, replacement tires should be of the same TPC specification number as the originals. If P metric tires must be replaced with other sizes, consult a tire dealer. Tire companies can best recommend the closest match of alphanumeric to P-metric sizes within their own tire lines. The metric term for measuring tire inflation pressure is the kilopascal (kPa). Tire pressure may be printed in both kPa and psi. One psi equals 6.895 kPa.
See the tire label or refer to Tire Size and Pressure Specifications for tire inflation pressures.
Tire Label
The tire label is permanently located on the rear face of the driver's door and should be referred to for tire information. It lists the maximum vehicle load, the tire size (including the spare tire), and the cold inflation pressure (including the spare tire).
Spare Tire
The notchback and the wagon come equipped with a full-sized tire on a steel wheel. The hatchback comes equipped with a reduced-sized temporary tire on a steel wheel.
Wheels
Wheels must be replaced if they are bent, dented, have excessive lateral or radial runout, leak air through welds, have elongated bolt holes, or if the wheel bolts won't stay tight or are heavily rusted. Wheels with excessive runout may cause vehicle vibration. Replacement wheels must be equivalent to the original equipment wheels in load capacity, diameter, rim width, offset, and mounting configuration. A wheel of improper size or type may affect wheel and bearing life, brake cooling, speedometer/odometer calibration, vehicle ground clearance, and tire clearance to the body and the chassis. The wheel offset is 49 - 1 mm (1.93 - 0.04 inches). Steel wheels may be identified by a two- or three-letter code stamped into the rim near the valve stem. Alloy wheels should have the code, the part number, and the manufacturer ID cast into the back side.
Inflation Tires
The pressure recommended for any vehicle line is carefully calculated to give a satisfactory ride, handling, tread life, and load-carrying capacity.
Tire pressure should be checked monthly or before any extended trip. Check the tires when they are cold, after the vehicle has sat for 3 hours or more, or has been driven less than 1 mile. Set the tire pressure to the specifications on the tire label located on the rear face of the driver's door. Tire inflation pressure is also given under Tire Size and Pressure Specifications. Valve caps or extensions should be on the valves to keep dust and water out. For sustained driving at speeds up to 140 km/h (85 mph), inflate the tires to the pressure recommended on the tire. Sustained driving at speeds faster than 140 km/h (85 mph), even if permitted by law, is not advised unless the vehicle has special high-speed tires available from many tire dealers. Tire pressures may increase as much as 41 kPa (6 psi) when the tires are hot.
Higher than recommended tire pressure can cause
^ Hard ride.
^ Tire bruising or damage.
^ Rapid tread wear at the center of the tire.
Lower than recommended pressure can cause
^ Tire squeal on turns.
^ Hard steering.
^ Rapid and uneven wear on the edges of the tread.
^ Tire rim bruises and rupture.
^ Tire cord breakage.
^ High tire temperatures.
Unequal tire pressures on same axle can cause
^ Uneven braking.
^ Steering lead.
^ Reduced handling.
^ Swerve on acceleration.
^ Torque steer.