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How to look after car tyres, Car tyre maintenance tips

The 4 tyres on a car is what holds the car on the road and responsible for the stability of the car. Your life depends on how good the car tyres are and money spent on tyres is worth it. It is not wise to save on tyre costs, our recommendation is always go for the best tyres available. When in doubt about any tyre on your car, simply throw it away and fit new tyres. Do regular check ups and maintenance on your car tyres. Below we explain some of the most important things to know about car tyres and give some important car tyre safety and maintenance tips.

Tyre Questions and Answers

Below is a list of the most frequently asked questions about car wheels and tyres. The Tyre Questions listed here are clickable links which takes you to the answers given further down on the page. Going through these Tyre questions and answers will give you a better understanding of car tyres.

Where to put new tyres front or rear

There is always a confusion when buying new tyres for a car whether to fit the new car tyres on front or rear. Many in India think that the best tyres of a car should be fitted on the front wheels. This is not correct. New or the best tyres of a car should be fitted to the rear back wheels. Why, because the front wheels can be controlled by steering it, but back wheels have no steering control. All the leading authorities recommend that the best or new tyres should be fitted on the back wheels.

This is what Michelin Tyres recommends on their website: "FOR COMPLETE CONTROL, FIT YOUR NEW TYRES TO THE REAR AXLE"

"Rear wheels are not connected to your steering wheel, which makes it extremely difficult to judge their grip while driving. We recommend that new tyres or the least worn tyres are fitted to the rear wheels to ensure:

• Better control in emergency braking or tight corners when the roads are slippery.
• Less risk of losing control of your vehicle, especially on wet surfaces
• Better road holding, particularly in difficult situations, whether your car is front or rear wheel drive"

Importance of air pressure in tyres

Maintaining the correct car tyre pressure is the one of the most important factor that affects the life of the car tyre and also for the safety of the car plus the riding comfort of the car. The recommended inflation pressure for a car's tyres is displayed in the owner's manual that comes with each new car. Also all cars sold in India has to have a label with the correct car tyre pressure stuck on the drivers door or the pillar which becomes visible when you open the driver's door. A cars tyre pressure should be checked at least once a month and before going on long trips. It is also a good practice to go around your car before starting it each morning and visually check all 4 car tyres to make sure that there are no flat tyres or under inflated tyres. When doing the regular monthly check of car tyres to check the pressure of the spare stepney tyre also.

The recommended car tyre pressure shown on the label is the cold tyre pressure, that is the pressure in the car tyre in the morning before the car has been driven. The most accurate way to measure the tyre pressure is to use a portable tyre pressure gauge in the morning before starting the car. Driving slowly to a nearby pump of not more than about 5 Kilometers will not warm up the tyre, so the tyre pressure in this case can be considered as the cold tyre pressure.

Since India follows the metric system of measurement, all car manufacturers have to give the recommended Tyre pressures in India as Kg/cm² (Kilograms per centimeter square), but since internationally the psi (pounds per square inch) measurement is more common, you will also find the recommended car tyre pressure in PSI which will be written in brackets. For example the recommended tyre pressure for Maruti Swift DZIRE mentioned on the tyre pressure badge on front door side will say: Front 2.3 Kg/cm² (33 psi) and Rear: 2.0 Kg/cm² (29 psi). The exact conversion rate is one Kg/cm² = 14.223 psi.

The recommended car tyre pressure is for normal loads like 2 adults and 2 kids in the car. But if your car is over loaded with say 5 big adults and plenty of luggage and you are driving a long distance, then the tyre pressure should be increased by about 4 PSI.

If the car is run with less tyre pressure the tyre will get heated up fast and also the milage of the car will go down, since there will be more rolling resistance to the tyre. If the car tyre is over inflated with higher pressure then the road grip of the tyre will be reduced and the stability of the car will suffer. In both cases of over and under inflation of car tyres, the life of the car tyres will be reduced.

Why put Nitrogen in car tyres? Nitrogen gas filling in tyres advantages

The recent trend is to use Nitrogen gas to fill tyres. The reason why nitrogen gas used in tyres can be attributed to the use of Nitrogen gas to fill tyres of racing cars and airplanes. The reason why airplanes use nitrogen is that, unlike normal compressed air, nitrogen gas is very dry. At high altitude where the planes fly, the temperatures are below freezing and if there is any moisture in the airplane tyres, it will freeze and form ice. This ice inside the airplane tyres will unbalance the airplane wheels when landing.

The tyres of racing cars become very hot while racing at very high speeds, so they cannot have moisture in their tyres, because the moisture water will boil and increase the tyre pressure too much. Hence they use dry nitrogen in their tyres.

In India in places where there are freezing temperatures it may be justified to use Nitrogen gas to fill car tyres. But in the rest of India, car tyres on Indian roads will never reach that low or high temperature to cause freezing or the moisture inside tyres to boil and form steam which will increase the tyre pressure. Hence the use of Nitrogen to fill tyres of passenger cars in India is not required.

Some say that Nitrogen will prevent corrosion of the car wheels, but this is very far fetched and should not be believed. Another benefit of Nitrogen filling of tyres claimed is that since the Nitrogen gas molecule is larger than an oxygen molecule, it will not seep out of the tyre and cause tyre pressure to go down. This may be true to an extent, but since air is almost 79% Nitrogen and only about 21% is Oxygen, the difference in the time of the pressure loss is minimal. Just to give an example, if the pressure drop is 1% every 50 days for an air filled tyre, then for a nitrogen filled tyre a pressure drop of 1% will take about 55 days. The difference is negligible.

Our recommendation regarding Nitrogen filling of car tyres in India is that it is not necessary, but if you feel it will benefit you, please go ahead. Nitrogen can do no harm to your car tyres even though the benefits are doubtful.

Why use wide tyres for cars

The main reason most opt for wider car tyres is for the looks of the car. The important thing to keep in mind is that the outer diameter of the new wide tyres should be the same as the original fitted tyres of the car, because the car speedometer and odometer are calibrated using the cars original tyre size.

So are wider car tyres better than narrow ones for cars? We will answer by giving the advantages and disadvantages of wider tyres for cars:

Wider tyre advantage for cars

• Wider tyres are better when running over sand and muddy surfaces, since they will not get stuck in the sand as quickly as narrower tyres.
• Wider tyres are more stable while cornering and do not skid that easily.
• Better braking performance with wider tyres
• Wider tyres usually makes the car look better

Disadvantages of wider tyres

• The main disadvantage of using wider tyres is less mileage. This is because the rolling resistance of wider tyres is more than narrower tyres.
• Wider tyres hydroplane when it goes fast over water on the road. Hydroplaning means that the fast moving tyre floats on the water and there is no contact with the road surface. Hydroplaning of tyres is a very dangerous phenomenon. Usually tyre manufacturers have special thread designs to prevent hydroplaning of tyres, but at greater speeds these thread designs do not help. The fact is that wider tyres hydroplane at lower speeds than narrower tyres.
• Wider tyres mean more steering force required to turn the front wheels. If you fit wider tyres to a car without power steering, then it will be very difficult to steer the car.
• When fitting wider tyres usually the rim size is upsized, for example, using a 14 inch rim instead of the old 13 inch rim. This practice of upsizing the rim is called 'Plus Sizing'. Increasing the rim size by one inch is referred to as 'Plus one' and 'Plus two' for a 2 inch rim size increase and so on. With the increased rim size the height of the tyre reduces to match the outer diameter of the original tyre. Thus the tyre becomes a lower profile tyre. The disadvantage of lower profile tyres is that the rim can get damaged more easily due to less height of the tyres.

What is tyre rotation in a car? Correct car tyre rotation

Tyre rotation in a car is the practice of interchanging the car tyres in a set pattern to prolong the life of the car tyres. The diagram here shows the right method of tyre rotation as recommended by Bridgestone tyres and all tyre manufacturers.

The reason why tyre rotation is important is because the thread of each tyre in a car wears out in a different way. The correct car tyre rotation is recommended by tyre manufacturers after a lot of research on the best way to even out the tyre thread wear on all the 4 car tyres. Tyre rotation will make your tyres last longer.

The recommended interval for tyre rotation is once every 5000 to 8000 kilometers even though the tyres may not show any visible signs of uneven thread wear. Note that the correct tyre rotation sequence is different for front wheel drive cars and rear wheel drive cars. For 4 wheel drive SUVs see the correct tyre rotation at the Bridgestone website

Difference between radial and bias ply tyres

Most new cars in India now come with radial tyres as standard. Older cars may be fitted with bias ply tyres. Radial tyres are far superior to bias ply tyres. The image here shows the difference between radial and ordinary tyre in the way the reinforcing cords in the tyre is laid out. In the bias tyre on the left in the image, the reinforcing cords are over lapping each other whereas in the radial ply tyre on the right in the image, the reinforcing cords are all in the same direction. This allows for cooler running tyres because there is no friction between the layers like in a bias ply tyre.

The side walls of a radial tyre are thinner and more flexible allowing for the thread of the radial tyre to stay evenly spread on the road, unlike a bias tyre where the thread is distorted and lifts off the road as shown in the image on the left. Radial tyres also have a steel belt under the thread which acts as a reinforcement for the thread of the tyre and also prevents sharp objects like nails from easily penetrating the thread of the tyre to cause a puncture. The reinforced thread of radial tyres on flexible side walls also helps increased fuel mileage because of less rolling resistance of the radial tyres. Also a radial tyre gives much more running Kilometers than a bias ply tyre.

What is meant by tube and tubeless tyres

As the name suggests a tubeless tyre has no tube inside the tyre and a tube tyre has a tube inside the tyre. The tubeless tyre is the newer generation of tyres and is much better. The advantages of a tubeless tyre over the tubed tyres are:

• Tubeless tyres run cooler because there is no friction between the surfaces of the tube and tyre
• Tubeless tyre is much more safer because it does not blowout like a tubed tyre and cause loss of vehicle control.
• Tubeless tyres are lighter which helps in more driving comfort
• Tubeless tyres gives better mileage and are longer lasting

Why alloy wheels are better

Even though most users of alloy rim wheels do so to enhance the beauty of their cars, there are some advantages of using aluminium alloy wheels in cars. The reasons why aluminium alloy wheels are better is mainly due to the reduced weight or mass of the rotating wheels resulting in lower inertial forces. The advantages and disadvantages of using alloy wheels for cars are explained as follows:

• Aluminium Alloy wheel rims are lighter than steel rims and hence give better braking and handling of the car due to lower inertia forces.
• Alloy wheels conduct heat better and the design of the car alloy wheels may help in faster dissipation of heat build up in the car tyres.
• Disadvantage of alloy wheels, especially with lower profile tyres, is that it could get damaged when running over pot holes and larger stones. Alloy wheels are difficult to repair if damaged and usually means buying a new one.
• Another disadvantage is that alloy wheels are expensive.
• Many argue that if it is looks that is the main aim of having alloy wheels, the the same effect could be had with good wheel covers for steel wheel rims.

What is car wheel balancing

Wheel balancing is done to prevent vibrations in the car due to an unbalanced wheel. The rotational balance of a wheel is done in a good tyre shop where the car wheel with tyre is put on a computerized machine and spun at high speed. The machine will point out where weights have to be placed to balance a car wheel. Without wheel balancing the tyres will vibrate and it will feel uncomfortable in the car. Also an out of balance car wheel will reduce the life of the car tyre. Tyre balancing is usually done together with wheel alignment at least once every 10,000 kilometers.

What is car alignment? Why car needs wheel alignment?

It is important that all the four car tyre threads spread evenly on the road and that all the wheels of the car point straight ahead in one direction when it is driven straight. This is what we mean by alignment of a car. The angles of the front suspension of a car are adjusted to correct the alignment of a car. Since the rear wheels are not steerable they usually do not have an alignment problem. Some of the symptoms of car needing wheel alignment are:

• The side of a car tyre tread is being worn out.
• The car keeps pulling to one side, left or right, when driving straight ahead.
• You need to keep the steering off centre when driving straight.
• The steering is vibrating when driving.

The usual reason why a car goes out of alignment is when the car accidentally hits a road hump or a pothole at speed. Also regular driving over rough roads tends to put a car out of alignment faster. It is always a good practice to check your cars alignment if you had any major incident of hump or pot-hole jumping. Otherwise a cars alignment and wheel balancing should be done every 10,000 Km and whenever you change tyres.