Posts Tagged ‘Wheel’

Legalities of tyres

There are two options either to pay a fine for making use of illegal tyres or pay out for the tyres so that they are safe and legal. The law is in place, which has certain guidelines that everyone has to comply with in relation to their car tyres.

The driving of damaged or worn out tyres can result in the fine or result in
MOT failure. It may even affect the insurance policy of the car as well. The legal issues need to be resolved but the most important thing is to stop using the damaged or worn out tyres as they endanger the lives of its users.

The car has to be maintained at peak performances and the easiest way is to maintain proper tyres by regularly keeping a check on formation of lumps or bumps or any kind of wear and tear that occur due to the separation or partial structural failure.

The cut or tear should not exceed the length of 25mm or 10 % of the tyre’s width else the tyre needs to be replaced with a functional one as deep cuts may cause damage to the tyre’s inner cords. The tyre’s internal plies should be protected from outside exposures. And any tyre that is being fitted to the vehicle should be compatible with tyres of other wheels. One should ensure that the tyre used in the car or trailer is of permissible standards and doesn’t cause damage to the road as well as its passengers.

The legal tyre maintenance suggests that all car tyres ought to be puffed up to accurate air demands as per the recommendation of car manufacturer or tyre manufacturer. Some tyres require to be maintained at partially inflated state.

The officially permitted tread deepness of 1.6mm is the minimum requirement for car tyres. This tread depth should be throughout a continuous band in the center ¾ of the tread and around the entire circumference. The said tread depth is mandatory and the minimum legal requirement wherein the original tread pattern must be visible as well.

Carrying of spare tyres is neither mandatory nor having a spare tyre is illegal. But the spare tyres should always comply with the legal standards.

The biggest risk of making use of damaged tyres in cars or trailers is that they are a dangerous proposition for the passengers within the vehicle as well as other people and vehicles on the road. The use of illegal or damaged tyres is punishable under the law.

The traffic police can issue Fixed Penalty notices to such offenders. In case the offenders don’t comply with the charges they can be prosecuted and even arrested. The legal notices are issued in the name of driver as well as the owner, incase he/she not the same person.

A court can compel fines up to a maximum of $2,500 and three penalty points. If a car has added flawed tyre, a directive can be issued for each prohibited tyre.

Certain circumstances require total disqualification.

Effects of pressure variances in tyres

Since the day the tyre was invented or more precisely rediscovered as in way the tyre is simply a wheel that has been remodeled to adhere to the modern means of transports. The tyre that is being used today has undergone a lot of changes from the time they were introduced for the first time. The scientific growth aided by technological developments has blended with growing needs of the customer to improve the performances of tyres manifolds.

The following are the areas, which get affected due to pressure variances in the tyres:

 Braking distances
 Fuel economy
 Gripping on the road in normal conditions and on bends
 Wet weather driving conditions

Tyres that are either balding or have been improperly inflated tend to reduce the grip of the wheels on the surface of the roads. The tyres tend to buckle slightly out of shape due to the application of wrong pressure and this may result in the vehicle to become unbalanced and harder braking could lead to tilting of the vehicle to a particular side.

Lower tyre pressures lead to the use of extra force for physically moving the car and this cause more fuel to be burned to keep the car moving. For shorter distances this is not a big issue but incase one is on long drive the prospect of burning more fuel is a nightmare as one has to pay for the petrol and it is a matter of concern.

The gripping of tyres under normal circumstances is greatly reduced due to presence of less air pressure in tyres. The risk is increased in bends as this may escort to deadly penalty. The lack of pressure in tyres causes the tyre to be pushed at a greater angle then they should actually be moving to. The entire scenario is that the area of tread is off the road slightly on one side and bottom of the sidewall is being used as exterior tyre on the supplementary. The loss in grip will considerably reduce the steer of the vehicle.

And finally the wet weather conditions are too harsh and require the tyres to be in perfect condition. Any sort of air pressure variances in the tyres can cause lot of damages. The tyres are provided with tread pattern to move the water away from under the front of the tyre to its sides without it having to go underneath.

If the tyre has water underneath it the surface of the tyre losses contact with the road and this phenomenon is called aquaplaning. Lower air pressures in tyre reduce the effect of treads and the tyres have a greater tendency for to lose grip in wet weather.
Aquaplaning is a severe consequence where the tyre has no grip on the road surface and the minimization of this phenomenon is key to safety. Tyres are provided with treads for negating the effect of aquaplaning but overused tyres or balding tyres tend to have less treads leading to loss of grip in wet road surfaces.

Cross Ply tyres versus Radial Ply Tyres

Cars make use of the radial tyres entirely but the ones fitted to motorbikes retain the cross-ply form of construction and even the tyre engineers state that radial tyres are not appropriate for motorbikes. This is in fact quite right as cars and motorbikes are very different and should have different tyre requirements. However, of late the radial tyres are considered to have benefits to offer to motorbikes as well.
Several piles of cord are laid on top of each other at a bias angle of 40 to 50° to make a cross ply tyre. This consequence in the creation of a cross at an direction of 80 to 100°. The layered and angled structure of ply tyres results in the tread not reacting in exact symmetry to that of the loads applied.
The symmetry is completely lacking in cross ply tyres and this can cause the tyre to run to one side nonetheless while rolling on a completely level and even surface. This effect is known as “Ply Steer”. The cross manufacture of the carcass efficiently forms parallelograms of thread imbedded in the rubber, this is not a sturdy form of construction and under driving or braking torque, upright load and centrifugal sound effects these parallelograms deform, which allows squirming of the contact area and tyre toss or diameter enlargement at elevated pace, reducing constancy and heating the tyre. Such heating eventually manifests itself as amplified rolling conflict.
By simple observation one can conclude that radial tyres create a greater and wider area of impression compared to the cross ply tyres. Such a fact highlights that radial tyres have better grip than cross ply tyres. Again in loaded conditions the radial tyres outscore the cross ply tyres as they have larger contact area with the surface of the road as they the tendency to become littile bit flat which is not the case in cross ply tyres.
Radial tyres contain less plies that is generally confined to one or two than the cross ply tyres that require three to four plies, so as to have greater flexibility in sidewalls. To maintain the entire tyre stiffness the reduction of sidewall height is required and thus results in lower profiles of 50 to 70 %. On the other hand the cross ply tyres make use of 90 to 100% of the profile. The lower profiler is an indication of having smaller diameter. The cross ply tyres have larger diameters in comparison to radial tyres of the same size. This trend contributed to the growth of 17” wheels while leading to the decline of the popular 16” wheels.
In the year 1984 radial tyres were introduced for the first time. The bias belted tyres were the most commonly used tyres until then. The cross-ply tyres were the next in line of production, which added circumferential belt plies. As and when the developments took place the older technology got replaced with newer ones giving way to improved tyre strength, agility and overall performances.