How a tyre is made

Tyre production is a complex technical process which requires stringent monitoring and quality control. This process consists of several manufacturing stages as stated below.

•	Mixing
Based on the required performance parameters, a specific composition is created to produce the most suitable tyre. Various grades of natural and synthetic rubber are blended together and mixed with carbon black and other chemical products.
•	Calendering
Textile fabric such as nylon, rayon and polyester are used for the casing and cap plies while steel cords are used for the belts. Both are coated with a film of rubber on both sides in the calendering process.
•	Tread and Sidewall Extrusion
The mixture of rubber is fed into an extruder which will produce continuous lengths of tread rubber. The rubber will be cut to specific lengths.
•	Bead Construction
For each particular tyre, steel wires are wounded on a bead former to become a bead core. The number of turns the steel wires are wounded will determine the diameter and strength for the tyre.
•	Tyre Building
The inner liner, body plies and sidewalls are placed on a building drum. The ply edges are wrapped around the bead core; the sidewalls are then moved into position. The tyre is shaped by inflation with two belts afterwhich a cap ply and treads are added.
•	Curing
The intermediate product is placed in a mould and cured in a curing press for a specific length of time, pressure and temperature. Once cured, the tyre is ejected from the mould.
•	Trimming
Excess rubber is trimmed from the cured tyre mechanically.
•	Inspection
Every tyre upon completion will be inspected visually and electronically to ensure uniformity and quality. Once checked, it will be sent for dispatch to be sold in the market.

Tread Patterns and Characteristics

Tread Pattern	Advantages	Disadvantages	Used for
Rib shape: Patterns dominated by multiple circumferential grooves	• Lower rolling resistance • Good steering control • Good directional stability	• Poor braking grip on wet roads • Poor acceleration grip on wet roads	• Sustaining high speeds on paved road surfaces • Truck or bus steer axles
Lug shape: Patterns with the groove arrangement perpendicular to the circumference of the tyre	• Excellent braking power and traction	• Tendency towards high noise when driven at high speed due to their high rolling resistance	• Dirt roads • Rear wheels of buses, industrial vehicles and dump
Rib-Lug shape: Combination of Rib and Lug	• Rib in the centre providing directional control • Lug at the sides gives good braking & driving power		• Paved and dirt roads • Front & rear wheels of trucks and buses
Block-shape: Patterns consisting of independent blocks divided by circumferential and lateral grooves.	• Good steering control and stability on snow covered and wet roads • Good water dispersal properties	• Tread blocks are smaller, tyre wear tends to be heavy	• Winter use • All-season passenger car tyres • Rear wheel use in ordinary applications
Asymmetric: Patterns differ on either side of the tyre.	• Optimize the opposing requirements of dry grip and water dispersal	• Must be positioned in the right way to be effective	• High speed cornering due to greater contact area which helps reduce tread wear on the outside of tyre • High performance and motor sport tyres
Directional pattern: Lateral grooves on both sides of the tyre which point in the same direction.	• Good driving force • Good braking performance • Good water dispersal - stability on wet roads	• Mounted in the direction of the tread pattern to be effective	• Passenger car tyre for high speed use

Markings on a tyre

On every tyre, you will be able to see some standard marking which describes the properties of the tyre. The markings include brand and model name of the tyre, tyre size, tyre aspect ratio, construction type, size of rim, loading rating and speed rating. A common string of numbers and letters can be seen on all tyres that look like this; 225/50 R 16 92V. A tread wear indicator is normally found on a tyre which indicate when you should change your tyre.

Brand and Model Name
This states the brand and model name for the specific tyre. The model name will differ with different tread patterns and functions.

Tyre Size
The first set of digits in the string of numbers and letters represent the tyre size. As shown in the example above, the first 3 digits represent the width of the tyre in millimeters.

Aspect Ratio
The next pair of digits represents the sidewall aspect ratio. This is the ratio of the tyre's width to its height. 50 in this case mean that the tyre has a height that is equal to 50% of its width. Tyres with an aspect ratio of 50 and below are referred to as low profile tyres.


Construction Type
The letter that follows (normally an R) represents the construction type of the tyre. R represents radial construction which is the most common type seen for passenger cars nowadays.

Loading Rating
The loading rating, also known as the load-index figure, is imprinted on the sidewall of the tyre. It denotes the maximum load capacity of a tyre when driven at maximum speed. A list of load indices (Li) and maximum weights (kg) is give below:

Li	kg	Li	kg
65	290	94	670
66	300	95	690
67	307	96	710
68	315	97	730
69	325	98	750
70	335	99	775
71	345	100	800
72	355	101	825
73	365	102	850
74	375	103	875
75	387	104	900
76	400	105	925
77	412	106	950
78	425	107	975
79	237	108	1000
80	450	109	1030
81	462	110	1060
82	475	111	1090
83	487	112	1120
84	500	113	1150
85	515	114	1180
86	530	115	1215
87	545	116	1250
88	560	117	1285
89	580	118	1320
90	600	119	1360
91	615
92	630
93	650

Speed Rating

Speed symbol	Maximum speed (km/h)	mph
N	140	87
P	150	93
Q	160	99
R	170	106
S	180	112
T	190	118
H	210	130
V	240	149
W	270	168
Y	300	186

Speed category	Maximum speed km/h	mph
ZR	>240	>149

Tread Wear Indicator
The tread wear indicator can normally be found on the shoulder or upper sidewall part of the tyres. They are normally located in the grooves, evenly spaced out over the tyre. These markers on the tyre will indicate the age of the tyre.

As you use the tyre more often, the tread pattern will eventually become flush with the remainder of the tread. This is a sign to change your tyre. The lack of tread depth implies poor control of the vehicle and may cause an accident.


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