Vehicle maintenance standards and guide lines are elaborated in the Maintenance Manual supplied to customers along with the vehicle by Original Equipment Manufacturers. Authorized workshops are available for the routine or emergency trouble shootings of the vehicle.
A tyre (air container) is the only part of a vehicle which bears the load, speed, friction, wear , tear, heat , cold, snow, mud and wet weather. Tyre suffers in any case when a vehicle goes in trouble. Tyre it self can create many troubles if not taken care of itself by the owner/driver. Let us discuss the tyre from it’s usage, service, re-purchase and disposition of used tyres.
TYRE SIZE DESIGNATION:
-P = Passenger car tire
-195 = Approximate cross section width in millimeters
-60 = Aspect ratio (height to width)
-R = Radial construction
-15 = Rim diameter in inches
-87 = Load index
-S = Speed rating symbol (S=max. speed of 112 mph)
The date of manufacture is embossed on every tyre produced by the tyre manufacturers. It is mandatory requirement and is implemented internationally.
-The pattern is of international Standard as per cited below:
-3417 means 34th week of 2017.
-4517 43109 : 45th Week of 2017 & Tyre serial number.
It is the standard inflation required to maintain in a tyre. In Pakistan we use pneumatic pressure in psi ( Per Square Inch) for Tyre air pressure. The sticker on the pole of driving side door have been pasted on all vehicles to inform the air pressure to be maintained in each tyre.
If we put a high pressure in the tyres it will create high noise and jerks / hard feelings in driving. A low air pressure normally damages the tyre itself in longer runs.
TOE IN – TOE OUT
Toe – in result when the front of the wheels are closer together than the rear of the wheels.
Toe – out is just the opposite.
Occurs when there is a heavy or light spot in the tyre. Static Imbalance result in a vibration felt through the car seat, floor and steering column.
Occurs when there is a heavy or light spot on the side or off-center of the tyre tread, side wall or wheel. Dynamic Imbalance result in an unstable ride or wheel shimmy.
PURCHASING TYRE FOR REPLACEMENT IN VEHICLE
It is recommended that replacement of tyres to be made from the specification provided by the vehicle manufacturer. Change in rim size, aspect ratio, tread width and side wall dimension shall effect the vehicle performance and may lead to damages of axels, shock absorbers, chassis, side fenders and it also invalidate the vehicle warranty.
Disposition of old tyres:
Generally we dispose off tyres to the dealer for resale as scrap. Scrap Tyres are used I making rubber bushes, furniture fillings, sole of shoes and it may be burnt as a fuel ( Environmental Hazard).
AGEING OF TYRES:
Age of tyre can be assessed from the manufacturing date, physical conditions may also define the time to replace the tyre. International Laws and regulations are available for tyre age. It ranges up to a maximum of Five years to allow the use of tyre. In few countries maximm tyre age is three years.
In certain special arrangement tyres can be stored in dark rooms with special wrappings for protection form heat , sunlight and oxygen. How ever a shelf life has never crossed the time of more than three years before the fitment.
By: SYED ABID RAZA, Ex: Divisional Manager
Quality Assurance & Head of HSE Department at GTL