Tyre Education
Tyres are designed and built to provide many thousands of miles of excellent service. For continued, safe use throughout the service life of the tyre, consumers must properly maintain their tyres and have them regularly inspected for signs of damage and abuse that can result in tyre disablement. The end of the service life of a tyre is affected by many factors that are independent of the chronological age of the tyre. The following information and recommendations are provided to assist consumers in maximizing tyre service life and to define conditions and practices affecting the service life of a tyre.
Topics
Tyre Maintenance and Safety
How to take care of your tyres
Consumers have the primary responsibility for the regular care and maintenance of their tyres. Tyres should be inspected at least once per month. The regular inspection should focus on proper inflation pressure, tread wear and tyre/wheel damage as detailed below. Having tread depth above the legal limit does not determine the service life of a tyre. Tyres must be properly maintained and routinely inspected for continued safe and proper use — even when tread depth remains. Tyres may need to be taken out of service even when tread depth above the legal limit remains. Regular inspection becomes particularly important the longer a tyre remains in use.
This monthly inspection should be supplemented by periodic rotation, balancing and alignment services. Inspection should occur whether or not the vehicle is equipped with a tyre pressure monitoring system.
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Replacing less than 4 tyres
When replacing tyres on a vehicle, it is recommended and preferred that all four tyres be replaced at the same time for continued optimal vehicle performance. However, for those cases where this is not feasible, below are some general guidelines to consider when replacing less than four tyres for a light vehicle, whether it is one or two tyres. If the vehicle manufacturer has alternate recommendations, always follow their recommendations.
Replacing One (1) Tyre - Replacing a single tyre on a vehicle can have an adverse affect on suspension systems, gear ratios, transmission, and tyre tread wear. If single tyre replacement is unavoidable, it is recommended that the single new tyre be paired with the tyre that has the deepest tread and both be placed on the rear axle. Placing greater traction on the rear axle on wet surfaces is necessary to prevent a possible over-steer condition and possible loss of vehicle control, especially during sudden manoeuvres.
Replacing Two (2) Tyres - When a pair of replacement tyres is selected in the same size and construction as those on the vehicle, the two newer tyres should be installed on the rear axle unless the new replacement tyres are of a lower speed rating. Generally, new tyres with deeper tread will provide better grip and evacuate water more effectively, which is important as a driver approaches hydroplaning situations. Placing greater traction on the rear axle on wet surfaces is necessary to prevent possible over-steer condition and possible loss of vehicle control, especially during sudden manoeuvres.
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Mixing brand and pattern
When tyres need to be replaced, do not guess what tyre size is right for the vehicle. Kindly refer to the vehicle owner’s manual, which tells you the size of the tyres (including the spare) that were mounted on the vehicle as original equipment (OE), or even better, consult a tyre service professional. It also includes the recommended cold inflation pressures for the front/rear axles and the spare tyre as well as the load capacity.
Always check the vehicle manufacturer’s recommendations for the OE tyre size, load capacity, inflation pressure, and speed symbol information (refer to section under “Speed index”) before replacing a tyre with a different size and construction.
It is recommended that all four tyres be of the same size, speed rating, and construction (radial, non-radial). In some cases, the vehicle manufacturer may require different sized tyres for either the front or rear axles.
Match tyre size designations in pairs on an axle, except for temporary use of a spare tyre.
Speed rated tyres - If the vehicle owner's manual specify speed rated tyres, the replacement tyres must have the same or higher speed rating to maintain vehicle speed capability.
If replacement tyres have lower speed capability than specified by the vehicle manufacturer, the vehicle's speed must be restricted to that of the replacement tyre. Also, vehicle handling could be affected. Consult vehicle manufacturer or tyre manufacturer for recommendations — and warn the consumer verbally and in writing that the speed must be restricted to the limits of the replacement tyre.
Four-wheel drive (4WD) and All-wheel drive (AWD) vehicles - If no instructions for tyre mixing appear in the vehicle owner's manual, kindly follow these guidelines:
DO NOT mix tyre sizes. All four tyres must be marked with the same tyre size, unless otherwise specified by the vehicle manufacturer.DO NOT mix radial and non-radial tyres. All four must be either radial or non-radial.
DO NOT mix tread pattern types such as all-terrain and all season.
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Tyre inspection
Consumers should check tyre pressure regularly (at least monthly, and before all long trips) and re-inflate tyres to the pressure specified on the vehicle’s manual. Pressure should be checked when tyres are “cold”; in other words, before they have been driven. Driving, even for a short distance, causes tyres to heat up and air pressure to increase. If the consumer notes regular loss of tyre pressure, the consumer should have the tyre(s) immediately inspected by a tyre service professional.
Consumers should inspect their tyres for cuts, cracks, splits, irregular wear, vibrations, or bulges in the tread and sidewall areas. These conditions may indicate a separation within the tyre body. If any of these abnormal conditions are observed or suspected, the consumer should have the tyre immediately inspected by a tyre service professional. It may be necessary to remove the tyre from the wheel for a complete inspection. Consumers are recommended to arrange for this inspection whenever the tyres are scheduled to be rotated.
After striking or impacting anything unusual in the roadway, a tyre service professional should demount the tyre and conduct a visual and tactile inspection of the tyre for damage. This is necessary because a tyre may not have visible signs of damage on its outer surface.
Tyres should be inspected for adequate tread depth. When the tyre is worn to the level of the built-in indicators at 1.6mm (2/32nd inch); or, if at any location on the tyre the tread groove depth is less than 1.6mm; or, if the tyre cord, steel or fabric is exposed, the tyre is dangerously worn and must be replaced immediately.
Tyres should be inspected for uneven wear. Wear on one side of the tread or flat spots in the tread may indicate a problem with the tyre or vehicle. Consult with a tyre service professional.
Rims, valves, valve stems, valve caps and lug nuts should also be inspected regularly. Bent or cracked valve stems or rims, or missing lug nuts or valve caps must be replaced.
The spare tyre should be maintained and inspected in the same manner and with the same frequency as all other tyres on the vehicle.
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Tyre rotation
It is important to check your tyres and wheels for signs of possible damage, and check your vehicle for any mechanical problems and correct if necessary. If you notice irregular or uneven tread wear, the tyres should be rotated to alleviate the problem.
You should follow the rotation pattern or procedure indicated in your limited warranty and the vehicle owner’s manual. We recommend you rotate tyres on front wheel drive vehicles and/or all season tyres on any vehicle every 12,000 km to equalize the rate of wear; however, rotate your tyres earlier if signs of irregular or uneven tyre wear arise, and have the vehicle checked by a qualified technician to determine the cause of the wear condition. The first rotation is the most important.
Besides monthly inspection of their tyres’ visual condition, consumers must also be aware of any change in dynamic performance such as increased air loss, noise or vibration. These conditions could be caused by internal damage to the tyre and may require that the tyre be removed from service immediately to prevent a tyre disablement. Consumers are recommended to consult a tyre service professional if any dynamic performance issues are noted.
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Tyre pressure
Driving on any tyre that does not have the correct inflation pressure is dangerous. Proper inflation pressure for your tyres may be found in the vehicle owner's manual.
Tyres lose some air pressure (about 2 psi) over the course of a month or so. However, should you need to add air once every few days, kindly have the tyre, wheel and valve checked - and if necessary, repair or replace the tyre.
Any underinflated tyre builds up excessive heat that may result in sudden tyre destruction.
Do not exceed the maximum pressure indicated on the tyre sidewall of passenger car tyres.
Tyre valve caps keep moisture and dirt out, so make sure they are on all your tyres. Also, when you have a tyre replaced, have a new valve stem assembly installed at the same time.
When any spare tyre is placed into service, its inflation pressure must be checked.
If you are replacing the original size tyres with tyres of a different size, you must consult a knowledgeable tyre dealer to determine the correct inflation pressure for your new tyres.
Checking Tyre Pressure
Vehicle owners are recommended to check the tyre pressure on a monthly basis, especially before long trips.
Never reduce the air pressure in a hot tyre. Failure to maintain correct inflation pressures may result in rapid wear and uneven tread wear, improper vehicle handling and excessive heat build-up which may result in tyre failure. (Evidence of air loss or repeated under-inflation requires tyre removal and expert inspection.)
Tyre Inflation with Nitrogen
Nitrogen is an inert (non-flammable) gas - basically, nothing more than dry air with the oxygen removed (air contains about 78% nitrogen). Nitrogen inflation does not harm tyres nor does it affect the warranty.
Proper tyre inflation, whether nitrogen or normal air, helps tyres wear longer, saves fuel, and helps prevent accidents. Under-inflation, regardless of the inflation gas, can make it harder to steer and stop your vehicle, result in loss of vehicle control, cause sudden tyre destruction, and lead to serious injury or death.
Nitrogen inflation will not prevent damage or loss of inflation due to road hazards. Nitrogen inflation will also not prevent tyre damage due to under-inflation, overloading, or off road service. Tyre inflation should always be checked and adjusted to the proper inflation pressure on a regular basis (at least monthly and before long trips), regardless of the inflation gas, to provide optimum tyre performance.
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Wheel alignment
Wheel alignment and balancing are important for safety and maximum mileage from your tyres. Inspect your tyres at least once a month for signs of uneven wear or damage (ie. cuts, cracks, splits, penetrations, bulges, and impacts.)
Uneven wear patterns may be caused by improper inflation pressure, misalignment, improper balance or suspension neglect. If not corrected, further tyre damage will occur. These conditions shorten the life of your tyres and may result in loss of vehicle control and serious personal injury.
You should have your alignment checked periodically as specified by the vehicle owner's manual or whenever you have an indication of trouble such as pulling or vibration.
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Tyre repair and patching
For repairs, see any tyre dealer at once. Never use a plug-only or patch-only repair. If any tyre has sustained a puncture, have the tyre dismounted and inspected internally by any tyre dealer for possible damage that may have occurred.
If the tyre has a puncture in the tread which exceeds 6mm (1/4-inch), any puncture in the sidewall, or if more than one radial cable per casing ply is damaged, the tyre must be removed from service and replaced.
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Used tyres
Consumers should be aware of possible serious risk associated with the installation and use of previously used tyres. While tyres are designed and built to provide many thousands of miles of excellent service, they must be maintained properly throughout their service life to achieve optimal performance.
Proper tyre maintenance includes regular (at least monthly) visual tyre inspections for signs of damage or abuse (ie. cuts, cracks, bulges, snags, irregular wear, etc.) and inflation pressure checks.
Tyres can be damaged over the course of their service life due to abuse or improper service, maintenance, repair, or storage conditions, and such damage can eventually lead to tyre failure. Only the original owner of a new tyre can know the full extent of a particular tyre’s service and maintenance, and the conditions of use or abuse the tyre has experienced.
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Spare tyre
Many vehicles are equipped with temporary spare tyres and wheels that are different from your regular tyres and wheels. Some may require higher inflation pressure, or the use of special canisters to inflate the tyre.
Do not exceed 80km/h (50mph) with a temporary spare. You may operate a vehicle with such a tyre within the limits indicated on the sidewall of the tyre, until it is convenient to repair the disabled tyre or replace it with one of the same size designation and construction as the other tyres on the vehicle.
Kindly refer to vehicle owner's manual and the tyre sidewall for instructions on proper use of a temporary spare.
Check the inflation in your spare tyre whenever the regular tyres are checked. A spare tyre with no air in it is no help to you in an emergency. If you have an inflatable spare, be sure to check the aerosol air inflation pressure canister to be sure it has not been damaged. If so, have it checked by a tyre service professional.
Remember, improper mounting and over inflation may damage the tyre or wheel and can result in an explosion that could cause serious injury and death.
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Driving habits
You may not realize it, but the way you drive can have a lot to do with how long your tyres will last and how well they perform. As you head down the road, there are a number of things to keep in mind.
Avoid hard cornering, rapid accelerations and abrupt braking as they put a lot of stress on your tyres. Smooth, safe driving is not only better for your tyres, but more importantly for you as a driver too.
Watch out for overloading. Driving on an overloaded tyre is hazardous. When your car is carrying too much weight, it can create excessive heat inside your tyres—and that can cause sudden tyre failure.
Never exceed the maximum load rating of your tyres, which you can find on the sidewall of the tyre, or in the owner’s vehicle manual. When you replace a tyre, make sure the new one has a load-carrying capacity equal to or greater than the tyres that originally came with your vehicle.
Tyre information
How to read a tyre sidewall
Tyre code, commonly molded onto the sidewall of the tyre, is described by an alphanumerical value. This code specifies the dimensions of the tyre, and some of its key limitations, such as load bearing ability, and maximum speed.
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Speed/Load index
Load Carrying Capacity
The load carrying capacity of the replacement tyres must always equal or exceed the load carrying the capacity of the original equipment tyres.
Refer to the vehicle owner’s manual for the recommended inflation pressures of the original equipment size tyres. These pressures must be maintained as a minimum. Do not exceed the maximum pressure indicated on the tyre sidewall. Tyres which are loaded beyond their maxi¬mum allowable loads will build up excessive heat that may result in sudden tyre destruction.
Speed Capability
The speed capability of the replacement tyres must always equal or exceed the original equipment tyres. When replacing tyres, refer to the vehicle owner’s manual for correct size.
When the tyre size contains a speed symbol, for example P205/60HR15 or P205/60R15 90H, the replacement tyre must have the same or higher speed rating symbol if the speed capability of the vehicle is to be maintained. If the replacement tyre is not speed rated, the speed capability of the vehicle is limited by the speed capability of the replacement tyre.
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Speed
|
Category
|
|
S
|
180 km/h (112 mph)
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T
|
190 km/h (118 mph)
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U
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200 km/h (124 mph)
|
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H
|
210 km/h (130 mph)
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V
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240 km/h (149 mph)
|
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*W
|
270 km/h (168 mph)
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*Y
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300 km/h (186 mph)
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* For tyres having a maximum speed capability above 240 km/h (149 mph), a "ZR: may appear in the size designation.
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LOAD INDEX - The load index
on a passenger Car tyre is a numerical code stipulating the maximum load (mass,
or weight) each tire can carry. |
|
CODE |
KILOGRAMS |
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CODE |
KILOGRAMS |
|
CODE |
KILOGRAMS |
|
CODE |
KILOGRAMS |
|
60 |
250 |
|
80 |
450 |
|
100 |
800 |
|
120 |
1400 |
|
61 |
257 |
|
81 |
462 |
|
101 |
825 |
|
121 |
1450 |
|
62 |
265 |
|
82 |
475 |
|
102 |
850 |
|
122 |
1500 |
|
63 |
272 |
|
83 |
487 |
|
103 |
875 |
|
123 |
1550 |
|
64 |
280 |
|
84 |
500 |
|
104 |
900 |
|
124 |
1600 |
|
65 |
290 |
|
85 |
515 |
|
105 |
925 |
|
125 |
1650 |
|
66 |
300 |
|
86 |
530 |
|
106 |
950 |
|
|
|
|
67 |
307 |
|
87 |
545 |
|
107 |
975 |
|
|
|
|
68 |
315 |
|
88 |
560 |
|
108 |
1000 |
|
|
|
|
69 |
325 |
|
89 |
580 |
|
109 |
1030 |
|
|
|
|
70 |
335 |
|
90 |
600 |
|
110 |
1060 |
|
|
|
|
71 |
345 |
|
91 |
615 |
|
111 |
1090 |
|
|
|
|
72 |
355 |
|
92 |
630 |
|
112 |
1120 |
|
|
|
|
73 |
365 |
|
93 |
650 |
|
113 |
1150 |
|
|
|
|
74 |
375 |
|
94 |
670 |
|
114 |
1180 |
|
|
|
|
75 |
387 |
|
95 |
690 |
|
115 |
1215 |
|
|
|
|
76 |
400 |
|
96 |
710 |
|
116 |
1250 |
|
|
|
|
77 |
412 |
|
97 |
730 |
|
117 |
1285 |
|
|
|
|
78 |
425 |
|
98 |
750 |
|
118 |
1320 |
|
|
|
|
79 |
437 |
|
99 |
775 |
|
119 |
1360 |
|
|
|
|
Example
Tyre Designation
|
Maximum Speed
|
|
P275/40R17 93W
|
270 km/h (168 mph)
|
|
P275/40R17 93Y
|
300 km/h (186 mph)
|
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Tyre manufacturing
Over 1 billion tyres are manufactured annually, making the tyre industry the majority consumer of natural rubber. Raw materials such as rubber, special oils, carbon black, silica and chemicals are used to produce numerous specialized components that are later assembled and cured.
A machine, known as the Banbury machine, combines these components into a homogenous black material, attaining uniform material dispersion.
Next is the assembling of the tyres. The inner-liner, a special rubber resistant to air and moisture penetration forms the tyre inner tube. This is followed by body plies and belts, made of steel and polyester, which gives a tyre strength and flexibility.
The belts are cut to precise angles and sizes, and this gives whatever handling characteristics any driver desires. Bronze-coated strands of steel wire are implanted into the sidewalls of a tyre to form a bead, ensuring air-tight fitting with the wheel rim. The tread and sidewalls are put into position over the body plies and belt, and they are pressed firmly together.
Finally, curing process sets in and for 15 minutes, the tyre is heated and cured over 150°C.
Every tyre is then being inspected, while random samples will be x-rayed, cut opened in search for flaws, and used in road tests to evaluate tyre handling and performance.
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Tyre patterns
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Directional - Lateral grooves on both sides point the same direction
|
|
|
Advantages:
|
Good driving force and braking performance.
Good water dispersal means good stability on wet roads.
Correct choice for fast driving styles.
|
|
Features:
|
Mounted in direction of tread pattern.
|
|
Usage:
|
Passenger car tyre for high speed usage.
|
|
|
Asymmetric - Tread pattern differs on each side
|
|
|
Advantages:
|
Good for high speed cornering thanks to greater
contact area.
Reduces tread wear on outside of tyre.
|
|
Usage:
|
High performance
and motorsport tyres.
|
|
|
Non-directional - The pattern of independent block, which the groove is connected
with each other
|
|
|
Advantages:
|
Good steering control and stability on snow covered and wet roadsGood water dispersal properties
on wet roads.
|
|
Usage:
|
Suitable
for all-season passenger car tyres.
Suitable
for back-wheel of Radial tyre of ordinary car
|
|
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Date of manufacture
A tyre’s date of manufacture is located on each tyre. A consumer can determine the date of manufacture by examining the series of letters and numbers called the Tyre Identification Number (TIN) on the tyre sidewall.
For tyres manufactured after the year 1999, the last four numbers of the TIN identify the week and year in which the tyre was manufactured. The first two numbers identify the week and the last two numbers identify the year of manufacture. Thus, a TIN ending with “3005” indicates that the tyre was made during the 30th week of 2005 and would appear as DOTXXXXXXX3005 on the sidewall of the tyre.
For tyres manufactured prior to 2000, three numbers instead of four indicate the date of manufacture. The first two numbers reflect the week and the last digit reflects the year of manufacture. Thus, a TIN ending in 308 indicates that the tyre was made in the 30th week of 1998 (or possibly 1988) and would appear as DOTXXXXXXX308 on the sidewall of the tyre.
All major brand tyre manufacturers warranty their tyres for 5 years from date of production. From the date of fitment, the tyre will have a warranty of another 3-4 years. There is no difference in the performance of a 3 year old tyre as compared to a 6 month old tyre.
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Country of manufacture
Most, if not all, major tyre manufacturers have manufacturing facilities all over the world, including Europe, America and many different parts of Asia.
The main reason for diverting production is to cater for the different market conditions and requirements around the world. In Asia, especially Southeast Asia, only summer tyres are required so the production of winter tyres in Southeast Asia is of a minimum. At the same time, diverting production in different parts of the world also helps to save costs for consumers, as logistics costs are greatly reduced.
In recent years, production in Asian countries greatly increased, due to the lower cost of production and market potential. The reason for the manufacturers to increase production in Asia is to create products which are more suitable, as well as lowering costs to ensure a more competitive product for consumers.
