Tire rotation or rotating tires is the practice of moving automobile wheels and tires from one position on the car, to another, to ensure even tire wear. Tire wear is uneven for any number of reasons. Even tire wear is desirable to maintain consistent performance in the vehicle and to extend the overall life of a set of tires.
By design, the weight on the front and rear axles differs which causes uneven wear. With the majority of cars being front-engine cars, the front axle typically bears more of the weight. For rear wheel drive vehicles, the weight distribution between front and back approaches 50:50. Front wheel drive vehicles also have the differential in front, adding to the weight, with a typical weight distribution of no better than 60:40. This means, all else being equal, the front tires wear out at almost twice the rate of the rear wheels, especially when factoring the additional stress that braking puts on the front tires. Thus, tire rotation needs to occur more frequently for front-wheel drive vehicles.
Turning the vehicle will cause uneven tire wear. The outside, front tire is worn disproportionately. Cloverleaf interchanges, and parking ramps turn right in left hand drive (otherwise known as right hand traffic) countries, causing the left front tire to be worn faster than the right front. Furthermore, right turns are tighter than left turns, also causing more tire wear. Conversely the sidewalls on the right tire tends to be bumped and rubbed against the curb while parking the vehicle, causing asymmetric sidewall wear. The symmetric opposite occurs in countries that drive on the left.
In addition, mechanical problems in the vehicle may cause uneven tire wear. The wheels need to be aligned with each other and the vehicle. The wheel that is out of alignment will tend to be dragged along by the other wheels, causing uneven wear in that tire. If the alignment is such that the vehicle tends to turn, the driver will correct by steering against the tendency. In effect the vehicle is constantly turning, causing uneven tire wear. Also, if a tire is under or over-inflated, it will wear differently than the other tires on the vehicle. Rotating will not help in this case and the inflation needs to be corrected.
Car manufacturers will recommend tire rotation frequency and pattern. Depending on the specifics of the vehicle, tire rotation may be recommended every 8,000 km (5,000 mi).[1] The rotation pattern is typically moving the back wheels to the front, and the front to the back, but crossing them when moving to the back. If the tires are unidirectional, the rotation can only be rotated front to back on the same side of the vehicle to preserve the rotational direction of the tires. Most unidirectional tires can be moved from side to side if they are remounted; tires with asymmetric rims are a rare exception. More complex rotation patterns are required if the vehicle has a full-size spare tire that is part of the rotation, or if there are snow tires.
To clarify; the pattern for asymmetrical tires to be rotated, or positioned, is for the tires on the driving axle of two-wheel drive vehicles to remain on the same side of the vehicle as they are moved to the non-driving axle, and for the tires on the non-driving axle to cross over to the opposite side of the vehicle as they are placed onto the driving axle. For all-wheel drive (AWD) vehicles and four-wheel drive (4WD) vehicles, it is recommended that the tires from each axle cross over as the fronts move to the rear and rears to the front. For the 4WD configuration, it is dependent upon how much 4WD driving is actually performed, whether it's controlled via mechanical/computerized devices or in vehicle controls, the recommendation will likely be found in the Owner/Operator manual or can be obtained by speaking to the manufacturer or dealership.
Current thinking stresses the desirability of keeping the best tires on the rear wheels of the vehicle, whether it is front, or rear wheel drive. The reason for this is that if the rear wheels lose grip before the front ones, an oversteer condition will occur, which is harder to control than the corresponding understeer which will happen if a front wheel is lost. This is also the case if a tire blows out, so the intuitive belief that the front steering/driving tires need to be the best quality is not the case.
In some cases (for example, BMW), automobile manufacturers may recommend performing no tire rotation at all. Additionally, some vehicles are designed (or retrofitted) with front and rear wheels of different sizes and unidirectional rotation treads, making rotation impossible.
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Factors affecting tyre performance
The factors which influence tyre life:
Inflation Pressure
The science and the technology that has gone into producing even the best quality of tyre will go waste if the tyres are not inflated to the recommended pressure – Pressure comensurating to the load carried. The best performance of tyres can only be achieved when the tyre is inflated to the designated pressure based on the load per tyre.
“Under inflation” or “Over inflation” on the tyre tend to impact tyre life, vehicle handling and safety. There are two factors with weight distribution of the vehicle. One is contact patch and other linked to the tyre wear. This result in heat buildup/tyre temperature and thus loss of tyre life, premature tyre removals, increased rolling resistance and fuel consumption.
“Under Inflation” is more common than Over inflation. Tyre users are not always conscious about maintaining or matching tyre pressure to the loads carried.
In pneumatic tyre the “Air carries the load”. The best tyre performance and lower tyre CPKM are obtained by maintaining correct tyre inflation pressure.
It is important to remember that the total weight (GVW) carried may not exceed the registered laden weight (RLW) or vehicle passing weight, but one side of the truck or one axle may be severely overloaded due to improper distribution of the load in the pay load platform or loading area.
Improper load distribution overloads the tyre(s). This condition combines with high speed , long hauls and load transfers result in tyres wearing fast and premature removal of tyres
Loads and Loading practices
It is important to remember that even one trip of the truck, with improper load distribution may cause irreversible damage to the tyres.
Speed
Excessive high speeds results in increased tyre running temperature. As the rubber gets heated up its modulus (stiffness) gets reduced.
Rubber being a good non conductor of heat the residual heat is retained causing increased tyre wear and separation of components.
Wheel Alignment
A vehicle is said to be properly align when all the steering and suspension components and set as per the vehicle manufacturer and when the tyre wheel assembly are running straight and true.
Proper alignment is necessary for perfect vehicle control, uniform and even tyre wear and safety.
Recommended to get the vehicle alignment checked and corrected as per vehicle owner’s manual as soon as tyre are wearing unevenly or ride handling problems(vibrations, pulling to one side etc).
Wheel Balancing
A wheel which is not properly balanced may setup vibrations which can affect steering control. Wheels, tyres and tubes are usually checked for balance before leaving factory.
This balance is achieved by positioning weights on the wheel to counterbalance heavy spots on the tyre wheel assembly.
Properly balanced tyres are important for driving comfort and long tyre life.
sTyres should be balanced when they are mounted on the wheels for the first time or when they are removed for repair or periodically as per vehicle manufacturer’s recommendations.
Tyre rotation
Rotation of tyre in a vehicle is recommended for a uniform tyre tread wear on all wheel position to achieve optimum tyre life.
It is prefferred to rotate tyres as per vehicle manufacturers recommendation or in case of any uneven tyre wear noticed.
It is suggested to check wheel alignment, wheel balance and suspension before the tyres are rotated.
Rotation patterns /pictures to be incorporated.
Road Conditions
Vehicle /tyre operating conditions which significantly influence tyre life both in terms of new tyre life and structural durability.
Rough/abbrrasive road surface
Paved road
Straight road
Broken up roads
Hilly windings roads
Unmade country roads
Driving habits
Careful driving habits will ensure optimum tyre life, unavoidable damages besides avoiding serious road accidents. Some of the habits which cause serious damages to tyre and road accidents are:
Over speeding
Speeding over pot holes, stone etc.
Quick starts and sudden stops
Riding over road divider and other obstacles
Sharp turns at high speeds
Hitting the road, curbs, objects etc.
Running on improperly inflated tyres
Seasonal Effects
Climatic and whether conditions in our country varies widely from region to region. Dry and extremely hot during summer, extreme cold during winter and rains during monsoon.
This variation in climatic conditions influence tyre life in terms of mileage and structural durability.
Do's & Dont's
Tyre Pressure checks including the spare tyre must be done regularly at least once in two weeks.
Tyre pressure should be checked using an accurate pressure gauge.
Tyre pressure should be checked when tyres are cold.
Under inflation and over inflation will cause rapid tread wear and premature tyre failures.
Tyre pressure should always be maintained as per the vehicle manufacturers recommendations, mentioned at information placard, at door, owners manual.
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TIPS & ADVICE
How often should I rotate my tires?
Your tires should be rotated every other oil change, or every 5000 miles. Neglecting to rotate tires is a major cause of premature tire wear
Is it really necessary to replace my timing belt at the manufacturer recommended interval?
YES. The failure of a timing belt in many cars can result in major engine damage. The cost of repairing an engine with a broken timing belt is much greater than the cost of a timing belt replacement.
What does it mean if my “check engine” or “service engine soon” light comes on?
There are many sensors and computerized components that manage your vehicle’s engine performance and emissions. When one of these fails, the “check engine” light is illuminated. Although your car may seem to run fine, it is important to have the issue addressed to prevent long-term problems or failure of emission tests.
What should I do if my car starts to overheat?
This is a very serious problem – if your car overheats for too long, you can damage your engine. As soon as possible, find a safe place to pull off the road and shut the engine off! Do not attempt to check the fluid level in the radiator as it can burn you. The best thing to do is have your car towed to a repair shop.
When should I get my oil changed?
You should get your oil changed every 3000 miles or as recommended in your vehicle’s owner’s manual. If intervals are extended, ensure you use oil that is capable of extended mileage changes.
What is that milky brown engine oil?
Milky brown engine oil is an indication of coolant in the oil. This can be caused by a blown head gasket (other gasket), a failed transmission cooler, or cracked casings. This condition is very serious and needs to be checked by a professional technician quickly.
How to make sure my car battery has a good electrical connection?
Battery cables and terminals should also be cleaned and inspected to make sure they provide a good electrical connection.
What is synthetic motor oil?
Synthetic motor oils can be a good choice for high output, turbocharged or supercharged engines, vehicles that are used for towing (especially during hot weather), or vehicles that are operated in extremely cold or hot climates.
Synthetic motor oils, though several times more expensive than mineral-based motor oils, can improve fuel economy and provide longer intervals between changes. They also provide instant lubrication on start-up.
When should I replace my car’s fuel filter?
To help ensure dependable, trouble-free performance, replace your car’s fuel filter approximately every 30,000 miles or as recommended in your vehicle’s owner’s manual.
When should I change my spark plugs?
For maximum fuel economy and peak engine performance, your spark plugs should be replaced every 30 months or 30,000 miles, unless your vehicle is equipped with 100,000-mile platinum tipped spark plugs.
I need to replace a burned out fuse, what should I do?
Always replace burned-out fuses with ones of the same amperage (printed on the fuse) and note that if a fuse continues to “blow,” you should have the circuit checked professionally by one of our technicians for defects.
Thanks to:
http://en.wikipedia.org/wiki/Tire_rotation
http://www.jktyre.com/Customer_Service/Tyre_Care.aspx
