Should your new tyres be installed in the front or back axle?

When most people buy new tyres, they tend to install them in the front axle. They give a number of reasons for doing so. Among such reasons are:
1.    With the engine in the front, new tyres should be in the front since they are stronger so should be able to effectively support the weight of the engine.
2.    New tyres will be less prone to suffer a blowout and since blowout of a front tyre is more dangerous than that of a rear tyre, it is safer to install new tyres in the front.
3.    Front tyres suffer the rigors of acceleration, braking, steering and bad road conditions more and so wear out faster than the rear tyres. So new tyres are better installed in the front.
 The above reasons sound logically but unfortunately following that logic would land you in serious trouble. It is downright dangerous to install new tyres in the front axle especially during the rainy season. Why? Because of a phenomenon called hydroplaning. What is hydroplaning?
HYDROPLANING.
You will observe that your tyres, if not worn out, have some grooves and channels on the treaded portion that is in contact with the ground. Those grooves and channels are designed to, among other functions, help to remove water under the tyres on a wet surface so that the tyre will maintain adequate contact with the road surface for proper traction.
A situation may arise where the channels are not able to remove water fast enough or where the channels are not deep enough because the tyres have worn out. In either situation, the tyres will not maintain contact with the road surface and will simply float on the pool of water. This phenomenon of floating on water because of lack of contact with the ground is called hydroplaning. It is dangerous and may lead to loss of control and a crash. When a vehicle is hydroplaning, application of the brakes will make matters worse!
Now let us consider the effects of hydroplaning with new tyres in (a) the front axle and (b) the back axle.
NEW TYRES IN THE FRONT AXLE. (Old tyres at back axle)
New tyres, by nature, should have more tread depths than tyres in use. So the tyres at the back – because they have less tread depths – will hydroplane before the new tyres in front. With the rear tyres hydroplaning first, a situation called OVER STEERING may occur. This is a situation where the rear tyres will lose traction before the front tyres and the rear of the vehicle begins to slide.
Oversteering is far more difficult to control, and in addition to the initial distress felt when the rear of the car starts sliding, quickly releasing the gas pedal in an attempt to slow down may actually make it more difficult for the driver to regain control, possibly causing a complete spinout, loss of control and a crash.
NEW TYRES AT THE BACK AXLE (old tyres in front axle)
When you have new tyres at the back axle, the old tyres in the front will hydroplane before the back tyres. This may lead to UNDERSTEERING. This means the vehicle will continue to move in the straight forward direction even when you want to steer it either to the left or to the right. This is easier to control. By easing up on the gas pedal, the vehicle will slow down and make it very easy for the driver to control.
TESTING EXPERIENCE
Members of The Tire Rack team had the chance to experience hydroplaning at Michelin’s Laurens Proving Grounds. Participants were allowed to drive around a large radius, wet curve in vehicles fitted with tires of different tread depths – one vehicle with new tires on the rear and half-worn tires on the front, and the other with the new tires in the front and half-worn tires on the rear.
 The ability to sense and control predictable understeer with the new tires on the rear, and the helplessness in trying to control the surprising oversteer with the new tires on the front was emphatically proven. It is better to experience this phenomenon in the safe, controlled conditions of Michelin’s Laurens Proving Grounds rather than in traffic in a rainstorm.
In case there is any doubt, when tires are replaced in pairs, the new tires should always be installed on the rear axle and the worn tires moved to the front.
SAFER TO REPLACE YOUR TYRES IN PAIRS, IF NOT IN FOURS.
When you have problem with any of your tyres and you want to replace it, it is advisable you equally replace the other tyre on the same axle with the bad tyre so that you have tyres that are exactly the same make, same age, same physical conditions, same size –  the same everything – on same axle. This will make for vehicle stability, effective control and better handling. Infact, the ideal thing is to change all the four tyres at the same time.
THOSE YELLOW/RED LINES AND DOTS ON A NEW TYRE WHAT DO THEY MEAN?
When you buy new tyres, you will observe that most of them have red or yellow lines running on top and round the entire perimeter of the tyre and red or yellow dots on the tyre’s side walls. Are those marks simply decorations or are they there for information? They are there with fascinating bits of information. Let’s start with the red or yellow dots.
The red and yellow spots.
When a tyre is made, the weight is not perfectly uniform throughout the entire size of the tyre. There are some areas of deformity where the weight is greater than in other portions of the tyre. That point is always marked with either red or yellow dot and is called the tyre’s high point. What do you do with the dots? When you are fixing the tyre onto the rim, you should align that spot with the inflation valve stem on the wheel. The point where the inflation valve stem is positioned on the wheel is another point of deformity on the wheel (the wheels are never perfectly circular). So synchronizing both points – the yellow or red dot on the tyre and the valve stem on the rim – will even out both deformities and make for a better wheel balancing, smoother ride, longer lasting tyres and better vehicle control. In some tyres, you have both the red and the yellow dot. Note, however, that the red and yellow spots may be seen on a tyre. If so, use the red dot.
The red and yellow lines.
The red or yellow lines run round on top of the tyres. The lines mark areas of imperfection. Notice that they don’t run on the center of the tyre. They are either nearer to the left of the top or to the right. If you are buying two tyres, rotate the tyres to ensure the lines are so positioned.  Don’t buy two tyres with the lines all on one side. Continue your search until you get two tyres with their lines properly positioned – one having the line nearer to the left and the other with the line nearer to the right.
 What do you do with the lines? As pointed out above, you are advised to buy tyres in pairs. After mounting the tyres on the wheels, install them on the same axle ensuring that the lines are of equal distance from the center of the axle. There are two ways to do this.
With the front of the vehicle facing you, install the one with the line nearer to the right on the right hand side and the other one with the line nearer to the left on the left hand side. This way the lines on the two tyres are away from the centre of the axle. You can also achieve the equidistance condition by spinning the tyres (while they are standing) in either a clockwise or anti-clockwise direction to get the two lines in the inside position –  nearer to the centre of the axle. If you mount the tyres otherwise (one line inside and the other outside), your vehicle will be pulling to one side as you drive.
Mounting the tyres properly ensures the vehicle maintains a straight course as you drive and also reduces vibrations and rough ride that would have been otherwise present due to construction imperfections. You would also be saving your shock absorbers from an early damage.
Please educate your vulcanizer with the above information because they don’t know about it.
CHANGE YOUR VALVE STEMS.
With every change of tyre, you must replace the valve stem with a new one otherwise leakages could slowly occur that may lead to under-inflation without your knowing it. Under-inflation is a major cause of tyre blowouts.