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IAUTOINFO.COM: Automotive Tire

Automotive Information for the consumer



reading a tire


Everything You Need To Know -- Your Sidewall Has It
The side of your tire -- known as the sidewall -- contains all of the information you need to know about your tire.




Tire Type defines the proper use of the tire. For example, the "P" on the tire shown here means that this is a passenger car tire. If the tire had an "LT" designation, the tire would be for a ligh truck.
Tire Width is the width of the tire measured in millimeters from sidewall to sidewall. This tire width is 215 millimeters.
Aspect Ratio is the ratio of the height of the tire's cross-section to its width. On our example, 65 means that the height is equal to 65% of the tire's width.
Construction tells you how the layers of the tire were put together. The "R" stands for Radial which means the layers run radially across the tire. A "B" stands for bias construction which means that the layers run diagonally.
Wheel Diameter is the width of the wheel from one end to the other. The diameter of this wheel is 15 inches.
Load Index indicates the maximum load in pounds that the tire can support when properly inflated. You'll also find the maximum load elsewhere on the tire sidewall, both in pounds and kilograms.
Speed Rating tells you the maximum service speed for a tire. This rating relates only to tire speed capability and is NOT a recommendation to exceed legally posted speed limits.
DOT means that the tire complies with all applicable safety standards established by the U.S. Department of Transportation (DOT). Next to this is a tire identification or serial number -- a combination of numbers and letters up to 12 digits.
UTQG stands for Uniform Tire Quality Grading, a rating system developed by DOT.



construction type




Bias
Bias tire(or cross ply) construction utilizes body ply cords that extend diagonally from bead to bead, usually at angles in the range of 30 to 40 degrees, with successive plies laid at opposing angles forming a crisscross pattern to which the tread is applied. The design allows the entire tire body to flex easily, providing the main advantage of this construction, a smooth ride on rough surfaces. This cushioning characteristic also causes the major disadvantages of a bias tire: increased rolling resistance and less control and traction at higher speeds.
Belted Bias
A belted bias tire starts with two or more bias-plies to which stabilizer belts are bonded directly beneath the tread. This construction provides smoother ride that is similar to the bias tire, while lessening rolling resistance because the belts increase tread stiffness. However the plies and belts are at different angles, which lessens performance compared to radial tires.
Radial
Radial tire construction utilizes body ply cords extending from the beads and across the tread so that the cords are laid at approximately right angles to the centerline of the tread, and parallel to each other, as well as stiff stabilizer belts directly beneath the tread. The advantages of this construction include longer tread life, better steering control, and lower rolling resistance. Disadvantages of the radial tire include a harder ride at low speeds on rough roads and in the context of off-roading, decreased "self-cleaning" ability and lower grip ability at low speeds.
Solid
Many tires used in industrial and commercial applications are non-pneumatic, and are manufactured from solid rubber and plastic compounds via molding operations. Solid tires include those used for lawn mowers, skateboards, golf carts, scooters, and many types of light industrial vehicles, carts, and trailers. One of the most common applications for solid tires is for material handling equipment (forklifts). Such tires are installed by means of a hydraulic tire press.
Semi-pneumatic
Tires that are hollow but are not pressurized have also been designed for automotive use, such as the Tweel (a portmanteau of tire and wheel) which is an experimental tire design being developed at Michelin. The outer casing is rubber as in ordinary radial tires, but the interior has special compressible polyurethane springs to contribute to a comfortable ride. Besides offering run-flat capability, the tires are intended to combine the comfort offered by higher-profile tires (with tall sidewalls) with the resistance to cornering forces offered by low profile tires. They have not yet been delivered for broad market use.



performance Characteristics




Tread Wear
Friction between the tire and the road surface causes the tread rubber to wear away over time. Government legal standards prescribe the minimum allowable tread depth for safe operation.
There are several types of abnormal tread wear. Poor wheel alignment can cause excessive wear of the innermost or outermost ribs. Gravel roads, rocky terrain, and other rough terrain will cause accelerated wear. Over inflation above the sidewall max can cause excessive wear to the center of the tread. However, inflating up to the sidewall limit will not cause excessive wear in the center of the tread. Modern tires have steel belts built in to prevent this. Under inflation causes excessive wear to the outer ribs. Quite often the placard pressure is too low and most tires are under-inflated as a result. Unbalanced wheels can cause uneven tire wear, as the rotation may not be perfectly circular. Tire manufacturers and car companies have mutually established standards for tread wear testing that include measurement parameters for tread loss profile, lug count, and heel-toe wear. Also can be known as tire wear.
Dry Traction
Dry traction is measure of the tire's ability to deliver traction, or grip, under dry conditions. Dry traction increases in proportion to the tread contact area. Dry traction is also a function of the tackiness of the rubber compound.
Wet Traction
Wet traction is measure of the tire's ability to deliver traction, or grip, under wet conditions. Wet traction is improved by the tread design's ability to channel water out of the tire footprint and reduce hydroplaning. However, tires with a circular cross-section, such as those found on racing bicycles and motorcycles, when properly inflated have a sufficiently small footprint to not be susceptible to hydroplaning. For such tires, it is observed that fully slick tires will give superior traction on both wet and dry pavement.
Force Variation
The tire tread and sidewall elements undergo deformation and recovery as they enter and exit the footprint. Since the rubber is elastomeric, it is compressed during this cycle. As the rubber deforms and recovers it imparts cyclical forces into the vehicle. These variations are collectively referred to as Tire Uniformity. Tire Uniformity is characterized by Radial Force Variation (RFV), Lateral Force Variation (LFV), and Tangential Force Variation. Radial and Lateral Force Variation is measured on a Force Variation Machine at the end of the manufacturing process. Tires outside the specified limits for RFV and LFV are rejected. In addition, Tire Uniformity Machines are used to measure geometric parameters including Radial Runout, Lateral Runout, and Sidewall Bulge in the tire factory at the end of the manufacturing process as a quality check.
Balance
When a wheel and tire is rotated, it will exert a centrifugal force characteristic of its center of gravity. This cyclical force is referred to as balance, and a non-uniform force is referred to as imbalance or unbalance. Tires are checked at the point of manufacture for excessive static imbalance and dynamic imbalance using automatic Tire Balance Machines. Tires are checked again in the auto assembly plant or tire retail shop after mounting the tire to the wheel. Assemblies that exhibit excessive imbalance are corrected by applying balance weights to the wheels to counteract the tire/wheel imbalance.
To facilitate proper balancing, most high performance tire manufacturers place 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 high performance tire to wheel assemblies using these red (Uniformity) or yellow (Weight) marks.
Centrifugal Growth
A tire rotating at higher speeds will tend to develop a larger diameter, due to centrifugal forces that force the tread rubber away from the axis of rotation. As the tire diameter grows the tire width decreases. This centrifugal growth can cause rubbing of the tire against the vehicle at high speeds. Motorcycle tires are often designed with reinforcements aimed at minimizing centrifugal growth.
Rolling Resistance
Rolling resistance is the resistance to rolling caused by deformation of the tire in contact with the road surface. As the tire rolls, tread enters the contact area and is deformed flat to conform to the roadway. The energy required to make the deformation depends on the inflation pressure, rotating speed, and numerous physical properties of the tire structure, such as spring force and stiffness. Tire makers seek lower rolling resistance tire constructions in order to improve fuel economy in cars and especially trucks, where rolling resistance accounts for a high amount of fuel consumption.
The pneumatic tire also has the more important effect of vastly reducing rolling resistance compared to a solid tire. Because the internal air pressure acts in all directions, a pneumatic tire is able to "absorb" bumps in the road as it rolls over them without experiencing a reaction force opposite to the direction of travel, as is the case with a solid (or foam-filled) tire. The difference between the rolling resistance of a pneumatic and solid tire is easily felt when propelling wheelchairs or baby buggies fitted with either type so long as the terrain has a significant roughness in relation to the wheel diameter.
Stopping Distance
The use of performance oriented tires, which have a tread pattern and rubber compounds designed to grip the road surface, usually has slightly shorter stopping distances. However, specific braking tests are necessary for data beyond generalizations.
TKPH
Ton kilometre per hour (TKPH) is the measurement of the work load of a tire and is used for monitoring its work so that it is not put under undue stress which may lead to its premature failure.



use Classifications




Tires are classified into several standard types, based on the type of vehicle they serve. Since the manufacturing process, raw materials, and equipment vary according to the tire type, it is common for tire factories to specialize in one or more tire types.



Passenger and light truck types


High Performance
High performance tires are designed for use at higher speeds. They feature a softer rubber compound for improved traction, however the soft rubber has a shorter tread life.
High performance street tires have a tendency to sacrifice wet weather handling by having shallower water channels, which provide more rubber tread surface area for dry weather performance.The ability to provide a high level of performance on both wet and dry pavement varies widely among manufacturers.
Mud and Snow
Mud and Snow, (or M+S, or M&S), is a classification for specific winter tires designed to provide improved performance under low temperature conditions. The tread compound is usually softer, which wears more quickly at higher temperatures, but provides better grip on ice and snow.
A dedicated winter/snow tire, designated by the American Society for Testing & Materials, will bear the "Mountain/Snowflake Pictograph". Winter tires will typically also carry the designation MS, M&S, or the words MUD AND SNOW.
Some winter tires may be designed to accept the installation of metal studs for additional traction on icy roads. The studs also roughen the ice, thus providing better friction between the ice and the soft rubber in winter tires. 
Other winter tires rely on factors other than studding for traction on ice, e.g. highly porous rubber that adheres to the wet film on the ice surface.
Mud tires are specialty tires with large, chunky tread patterns designed to bite into muddy surfaces. The large, open design also allows mud to clear quickly from between the lugs. Mud terrain tires also tend to be wider than other tires, to spread the weight of the vehicle over a greater area to prevent the vehicle from sinking too deeply into the mud. However in reasonable amounts of mud and snow, tires should be thinner. Due to them having a thinner wheel base, the tire will have more pressure per square inch on the road surface, thus allowing the tires to penetrate the snow layer and grip harder snow or road surface beneath.
All Season
The All Season tire classification was developed for use on dry and wet roads during summer conditions and also for use under winter conditions. The type of rubber and the tread pattern best suited for use under summer conditions does not give good performance on snow and ice. The all-season tire is a compromise, and is neither an excellent summer tire nor an excellent winter tire. All-Season tires are also marked for mud and snow the same as winter tires.
All-Terrain
All-terrain tires are typically used on SUVs and light trucks. These tires often have stiffer sidewalls for greater resistance against puncture when traveling off-road, the tread pattern offers wider spacing than all-season tires to remove mud from the tread.
Spare
Some vehicles carry a spare tire, already mounted on a wheel, to be used in the event of flat tire or blowout. Spares have a short life expectancy, and low speed rating.
Run-Flat
Several innovative designs have been introduced that permit tires to run safely with no air for a limited range at a limited speed. These tires typically feature strong, load-supporting sidewalls.
Heavy Duty Truck
Heavy duty tires are also referred to as Truck/Bus tires. These are the tire sizes used on vehicles such as commercial freight trucks, dump trucks, and passenger buses. Truck tires are sub-categorized into specialties according to vehicle position such as steering, drive axle, and trailer. Each type is designed with the reinforcements, material compounds, and tread patterns that best optimize the tire performance.
Off-The-Road (OTR)
The OTR tire classification includes tires for construction vehicles such as wheel loaders, backhoes, graders, trenchers, and the like; as well as large mining trucks.
Racing
Racing tires are highly specialized according to vehicle and race track conditions. Tires are specially engineered for specific race tracks according to surface conditions, cornering loads, and track temperature. Tires also have been specially engineered for "drifting" in which vehicles engage in exaggerated skids and slides.
Industrial
The Industrial tire classification is a bit of a catch-all category and includes pneumatic and non-pneumatic tires for specialty industrial and construction equipment such as skid loaders and fork lift trucks.
Sport Touring - these tires are generally not used for high cornering loads, but for long straights, good for riding across the country.
Sport Street - these tires are for aggressive street riders that spend most of their time carving corners on public roadways. These tires do not have a long life, but in turn have better traction in high speed cornering. Street and sport street tires have good traction even when cold, but when warmed too much, can actually lose traction as their internal temperature increases.
Track or Slick - these tires are for track days or races. They have more of a triangular form, which in turn gives a larger contact patch while leaned over. These tires are not recommended for the street by manufactures, and are known to have a shorter life on the street.



tire terminology




Bead
The bead is that part of the tire which contacts the rim on the wheel. The bead is reinforced with steel wire, and compounded of high strength, low flexibility rubber. The bead seats tightly against the two rims on the wheel to ensure that a tubeless tire holds air without leakage. The bead fit is tight, to ensure the tire does not shift circumferentially as the wheel rotates. The width of the rim in relationship to the tire is a factor in the handling characteristics of an automobile, because the rim supports the tire's profile.
Contact Patch
The contact patch, or footprint, of the tire, is merely the area of the tread which is in contact with the road surface. This is the area which transmits forces between the tire and the road via friction. The length-to-width ratio of the contact patch will affect steering and cornering behavior.
Inflation Pressure
Tires are specified by the vehicle manufacturer with a recommended inflation pressure, which permits safe operation within the specified load rating and vehicle loading. Most tires are stamped with a maximum pressure rating (for USA only). For passenger vehicles and light trucks, the tires should be inflated to what the vehicle manufacturer recommends, which is usually located on a decal just inside the driver's door, or in the vehicle owners handbook. Tires should not be inflated to the pressure on the sidewall; this is the maximum pressure, rather than the recommended pressure.
If tire pressure is too high, the tire contact patch is reduced, which decreases rolling resistance. However, ride comfort is reduced, but traction is not always reduced, stopping distance is not always increased. Also, going above max sidewall pressure rarely results in the center of the tire wearing more than the shoulder.
If tire pressure is too low, the tire contact patch is increased, increasing rolling resistance, tire flexing and friction between the road and tire. This "under-inflation" can lead to tire overheating, premature tread wear, and tread separation in severe cases. Braking distance did not statistically change as tire pressure increased, suggesting that a larger contact patch from under-inflation may not be a significant contributor for the conditions explored in these specific tests.
Inner Tube
Inner tubes are torus-shaped balloons made from a material impervious to air leakage, such as soft, elastic synthetic rubber. The inner tubes are inserted into the tire and inflated to retain air pressure.
Flat
A flat tire occurs when a tire deflates to the point where the metal of the wheel rim comes to ground level. This can occur as a result of normal wear-and-tear, a leak, or more serious damage. A tire which has lost sufficient pressure to cause it to become distorted at the bottom will impair the stability of the vehicle and may damage the tire further if it is driven in this condition. The tire should be changed and/or repaired before it becomes completely flat. Continuing to drive a vehicle with a flat tire will damage the tire beyond repair, possibly damage the rim and vehicle, and put the occupants and other vehicles in danger. A flat tire or low-pressure tire should be considered an emergency situation, requiring immediate attention to rectify the problem. (Some tires, known as "run-flat" tires, have either extremely stiff sidewalls or a resilient filler to allow driving a limited distance while flat, usually at reduced speed, without permanent damage or hazard.)
Hydroplaning (Aquaplaning)
Hydroplaning, also known as aquaplaning, is the condition where a layer of water builds up between the tire and road surface. Hydroplaning occurs when the tread pattern cannot channel away enough water at an adequate rate to ensure a dry footprint area. When hydroplaning occurs, the tire effectively "floats" above the road surface on a cushion of water - and loses traction, braking and steering, creating a very unsafe driving condition. When hydroplaning occurs, there is considerably less responsiveness of the steering wheel. The correction of this unsafe condition is to gradually reduce speed, by merely lifting off the accelerator/gas pedal.
Hydroplaning becomes more prevalent with wider tires.
Load Rating
Tires are specified by the manufacturer with a maximum load rating. Loads exceeding the rating can result in unsafe conditions that can lead to steering instability and even rupture. For a table of load ratings, see tire codes.
Replacing a tire on a vehicle with one with a lower load rating than originally specified by the vehicle manufacturer will often render the insurance invalid.
Rain Groove
The rain groove is a design element of the tread pattern specifically arranged to channel water away from the footprint. Rain grooves are circumferential in most truck tires. Many high performance passenger tires feature rain grooves that are angled from the center toward the sides of the tire. Some tire manufacturers claim that their tread pattern is designed to actively pump water out from under the tire by the action of the tread flexing.  This results in a smoother ride in different types of weather.
Retread
Tires that are fully worn can be re-manufactured to replace the worn tread. This is known as re-treading or recapping, a process of buffing away the worn tread and applying a new tread. Re-treading is economical for truck tires because the cost of replacing the tread is less than the price of a new tire. Re-treading passenger tires is less economical because the cost of re-treading is high compared to the price of a new tire. However, commercial truck drivers run the risk of "blow-outs", separation, and tread peeling from the casing, due to re-use of the tire casing. To reduce these problems, tire technicians and the retread plant must ensure the casing is in the best condition possible. Tires or casings with problems such as capped tread, tread separation, corroded belts or sidewall damage, or any run-flat or skidded tires, will be rejected.
In most situations, retread tires can be driven under the same conditions and at the same speeds as new tires with no loss in safety or comfort. The percentage of retread failures should be about the same as for new tire failures, but many drivers, including truckers, are guilty of not maintaining proper air pressure on a regular basis and if a tire is abused (overloaded, under-inflated, or mismatched to the other tire on a set of duals), then that tire (new or recapped) will fail.
Rotation
Tires may exhibit irregular wear patterns once installed on a vehicle and partially worn. Furthermore, front-wheel drive vehicles will wear the front tires at a greater rate compared to the rears. Tire rotation is the procedure of moving tires to different car positions, such as front-to-rear, in order to even out the wear, thereby extending the life of the tire.
Service Rating
Tires are often given service ratings, mainly used on bus and truck tires. Some ratings are for long-haul, and some for stop-start multi-drop type work. Tires designed to run 500+ miles per day carrying heavy loads require special specifications.
Shoulder
The shoulder is that part of the tire at the edge of the tread as it makes transition to the sidewall.
Sidewall
The sidewall is that part of the tire that bridges between the tread and bead. The sidewall is reinforced with rubber and fabric plies that provide for strength and flexibility. The sidewall transmits the torque applied by the drive axle to the tread in order to create traction. The sidewall, in conjunction with the air inflation, also supports the load of the vehicle. Sidewalls are molded with manufacturer-specific detail, government mandated warning labels, and other consumer information, and sometimes decorative ornamentation.
Over time, rubber degrades. Ford has recommended that tires be replaced when they are 6 years old to prevent sudden failure, even if the tire looks undamaged. In tropical climates, such as Singapore, tires degrade sooner than in temperate climates. Tires on seldom-used trailers are at the greatest risk of age-failure, but some tires are built to withstand idleness, usually with nylon reinforcement. In the past rayon was used in tires, but it ages quite quickly.
Sipe
Tread lugs often feature small narrow voids, or sipes, that improve the flexibility of the lug to deform as it traverses the footprint area. This reduces shear stress in the lug and reduces heat build up.  Sipes also provide greater traction in wet or icy conditions.
Speed Rating
The speed rating denotes the maximum speed at which a tire is designed to be operated. For passenger vehicles these ratings range from 99 mph (160 km/h) to 186 mph (300 km/h). For a table of speed ratings, see tire code.
Replacing a tire on a vehicle with one with a lower speed rating than originally specified by the vehicle manufacturer will often render the insurance invalid.
Tires- ring-shaped parts, either pneumatic or solid (including rubber, metals and plastic composites), that fit around wheels to protect them and enhance their function.
Pneumatic tires are used on many types of vehicles. Tires enable better vehicle performance by providing traction, braking, steering, and load support. Tires form a flexible cushion between the vehicle and the road.
Tire Pressure Monitoring System
Tire pressure monitoring systems (TPMS) are electronic systems that monitor the tire pressures on individual wheels on a vehicle, and alert the driver when the pressure goes below a warning limit. There are several types of designs to monitor tire pressure. Some actually measure the air pressure, and some make indirect measurements, such as gauging when the relative size of the tire changes due to lower air pressure. These systems are becoming mandatory in countries such as the United States.
Tread
The tread is the part of the tire which comes in contact with the road surface. The tread is a thick rubber, or rubber/composite compound formulated to provide an appropriate level of traction that does not wear away too quickly.
Treads are often designed to meet specific product marketing positions. High performance tires have small void ratios to provide more rubber in contact with the road for higher traction, but may be compounded with softer rubber that provides better traction, but wears quickly. Mud and snow (M&S) tires are designed with higher void ratios to channel away rain and mud, while providing better gripping performance.
Tread Lug
Tread lugs provide the contact surface necessary to provide traction. As the tread lug enters the road contact area, or footprint, it is compressed. As it rotates through the footprint it is deformed circumferentially. As it exits the footprint, it recovers to its original shape. During the deformation and recovery cycle the tire exerts variable forces into the vehicle. These forces are described as Force Variation.
Tread Void
Tread voids provide space for the lug to flex and deform as it enters and exits the footprint. Voids also provide channels for rainwater, mud, and snow to be channeled away from the footprint. The void ratio is the void area of the tire divided by the entire tread area. Low void areas have high contact area and therefore higher traction on clean, dry pavement.
Treadwear
The treadwear grade describes how long the tire manufacturers expects the tire to last. A Course Monitoring Tire (the standard tire that a test tire will be compared to) has a rating of "100". If a manufacturer assigns a treadwear rating of 200 to a new tire, they are indicating that they expect the new tire to have a useful lifespan that is 200% of the life of a Course Monitoring Tire. In general, manufacturers tend to overstate the treadwear of their tires in an effort to create the impression that their tires last a long time. The ability of manufacturers to report their own numbers makes comparison of treadwear ratings between companies useless. Ratings may still be useful within a manufacturer's own line of tires.
Valve Stem
The valve stem is a tube made of steel or rubber with a metal valve used to inflate the tire with air. Valve stems usually protrude through the wheel for easy access for inflation. Tires are inflated through a valve, typically a Schrader valve on automobiles and most bicycle tires, or a Presta valve on high performance bicycles. The rubber in valve stems eventually degrades. Replacement of the valve stem at regular intervals reduces the chance of failure.
Wear Bar
Wear bars (or wear indicators) are raised features located at the bottom of the tread grooves that indicate the tire has reached its wear limit. When the tread lugs are worn to the point that the wear bars connect across the lugs, the tires are fully worn and should be taken out of service.
Wheel
Tires are mounted to wheels that bolt to the hub. The inside edges of the tire are held on the wheel's rim. Automotive wheels are typically made from pressed and welded steel, or a composite of lightweight metal alloys, such as aluminum or magnesium. These alloy wheels may be either cast or forged.
Wheel Alignment
When mounted on the vehicle, the wheel and tire may not be perfectly aligned to the direction of travel, and therefore may exhibit irregular wear. If the discrepancy in alignment is large, then the irregular wear will become quite substantial if left uncorrected.
Wheel alignment is the procedure for checking and correcting this condition through adjustment of camber, caster and toe angles. These settings also affect the handling characteristics of the vehicle.



speed ratings




The code is made up of one or two letters, or one letter and one number. It indicates the maximum permitted speed that the tire can sustain for a ten minute endurance without being in danger.

Speed ratings do not indicate how well a tire handles or corners. They certify the tire's ability to withstand high speed.


Code MPH Code MPH
A1 3 L 75
A2 6 M 81
A3 9 N 87
A4 12 P 94
A5 16 Q 100
A6 19 R 106
A7 22 S 112
A8 25 T 118
B 31 U 124
C 37 H 130
D 40 V 149
E 43 Z over 149
F 50 W 168
G 56 (W) over 168
J 62 Y 186
K 68 (Y) over 186
If you never drive at speeds near the limits of your speed rated tires, you may choose to replace them with tires having a lesser top-speed rating.

In situations where tires having different top-speed ratings are mixed on a vehicle, the maximum speed certification is limited to the top-speed certification of the tire with the lowest speed rating.
Check Your Tire Inflation
Proper tire inflation is essential for safe driving and long tire life. It's wise to check your tires' air pressure at least once a month with an accurate tire pressure gauge. Be sure to check pressure while your tires are cold and have not been used recently. Even driving a mile will cause your tire pressure to increase and give you an inaccurate reading.
Check Your Tire Tread
Look at the tread wear indicator bar that's molded into your tires. The bars are located at the bottoms of the tread grooves in several locations around the tire. When a tire is so worn that these bars become visibly flush with the adjacent tread ribs, it's time to replace the tire.
Know What Certain Wear Patterns Mean
As tires wear, sometimes wear patterns emerge that can indicate problems with your vehicle or tires. If you see any of these patterns, have your tires checked by a professional Goodyear Retailer. Here are some wear patterns to watch for.
  • UNDER-INFLATION: Wear on both edgesUnder-inflation of a tire reduces its tread life by increasing the tread wear on its outside edges, or shoulders. It also generates excessive heat which reduces tire toughness. Finally, it reduces fuel economy through increased rolling resistance because soft tires make your vehicle work harder. Abnormal tire wear may also be caused by misalignment or mechanical problems.
  • OVER-INFLATION: Wear in center When a tire is over-inflated, the center of the tread bears most of the load and wears out faster than the outside edges. Uneven wear reduces the useful life of a tire. It could also be the result of misalignment or mechanical problems.
  • WORN PARTS: Cups or Dips in the tread Cupping (also called dipping) is most common on front tires, although rear tires can cup as well. It may be a sign that wheels are out of balance or that suspension or steering system parts are worn out.
  • MISALIGNMENT: Sawtooth edgesIf the edges of your tire tread take on a sawtooth or feathered appearance, it's because of erratic scrubbing against the road. The solution is an alignment correction.
Tire Balancing
If your tires are unbalanced, you'll notice vibration. This can lead to driver fatigue, premature or irregular tire wear and unnecessary wear to your vehicle's suspension. Your tires should be balanced when they are mounted on wheels for the first time or when they are remounted after repair. Check your tire balance at the first sign of vibration or shimmy.
Vehicle Alignment
Your vehicle is properly aligned when all of its suspension and steering components are working smoothly and when its tire and wheel assemblies are running straight and true. If you notice uneven tread wear, it could be due to a misalignment and your vehicle should be serviced by a professional.
Tire Rotation
While many people are knowledgeable enough to rotate their own tires, the procedure is especially quick and easy for a professional. Your vehicle's owner's manual will specify the proper rotation pattern and schedule for your vehicle. If no specific schedule is indicated, a good rule of thumb is to rotate your tires every 6,000 to 8,000 miles.
Tire Repair
Tire repairs should be made by a trained tire professional. Proper repair procedure includes dismounting the tire from the wheel. This allows for thorough inspection of the tire for damage, as well as the use of a patch and plug to repair any punctures that fall within the guidelines for repair.





IAUTOINFO.COM: AUTOMOTIVE TIRE

Automotive Information for the consumer