Anwan International : Tyres General Information - Sourcing & Outsourcing in China

Tyres Sidewall

When you look at the sidewall of a tyre, you will see plenty of information full with numbers, letters, symbols and codes. Here are some of the meanings:

	Key	Description
	A	Manufacturers or Brand Name
	B	Tyre size, construction and speed rating designations. Tubeless designates a tyre which requires no inner tube. See tyre sizes and speed ratings below. DIN-type marking also has the load index encoded in it. These go from a load index of 50 (190kg) up to an index of 169 (5800kg).
	C	Denotes type of tyre construction
	D	M&S denotes a tyre designed for mud and snow. Reinforced marking only where applicable
	E	Pressure marking requirement
	F	ECE (not EEC) type approval mark and number
	G	North American Department of Transport (DOT) compliance symbols and identification numbers
	H	Country where manufactured

On some tyres, the sidewall will also contain the temperature rating, traction rating and the tread-wear rating.

DOT & Tyre shelf life.

The DOT code (G) contains several different information. The first part contains a two-letter code identifying the manufacturer and its location. The last part contains a 4-digit code, whereby the first two indicates the week of the year and the last two is the year it was manufactured. So for example 2005 means it was manufactured in the 20th week of 2005.

Generally it is advisable not to buy and use any tyre that is over 6 years old, because the rubber in the tyres degrades over time.

E-Mark

The item F in the above diagram is the E-Mark code. All tyres sold in Europe after July 1997 must carry an E-mark. The mark itself is either an upper or lower case "E" followed by a number in a circle or rectangle, followed by a further number.

Tyre Sizes

A normal car with radial tyre size of 185/65HR13 means:

185 65 H R 13

This is the width in mm of the tyre from sidewall to sidewall when it's unstressed and you're looking at it head on (or top-down). This is known as the section width.

This is the ratio of the height of the tyre sidewall (section height), expressed as a percentage of the width. It is known as the aspect ratio. In this case, 65% of 185mm is 120.25mm - the section height.

This is the speed rating of the tyre.

This tells you that the tyre is a radial construction. Check out tyre construction if you want to know what that means.

This is the diameter in inches of the rim of the wheel that the tyre has been designed to fit on.

Speed Ratings

All tyres are rated with a speed letter. This indicates the maximum speed that the tyre can sustain for a 10 minute endurance without coming to pieces and destroying itself.

Speed Symbol	Max Car Speed Capability		Speed Symbol	Max Car Speed Capability
Speed Symbol	Km/h	MPH	Speed Symbol	Km/h	MPH
L	120	75	S	180	113
M	130	81	T	190	118
N	140	87	U	200	125
P	150	95	H	210	130
Q	160	100	V	240	150
R	170	105	W	270	168
			Z	240+	150+

"H" rated tyres are becoming the most commonplace & widely used tyres, replacing "S" & "T" ratings.

Load Indices

This is a numerical code associated with the maximum load the tyre can carry. These are generally valid for speed under 210km/h (130mph). The table below gives you most of the Load Index (LI) values:

LI	kg	LI	kg	LI	kg	LI	kg	LI	kg	LI	kg
50	190	70	335	90	600	110	1060	130	1900	150	3350
51	195	71	345	91	615	111	1090	131	1950	151	3450
52	200	72	355	92	630	112	1120	132	2000	152	3550
53	206	73	365	93	650	113	1150	133	2060	153	3650
54	212	74	375	94	670	114	1180	134	2120	154	3750
55	218	75	387	95	690	115	1215	135	2180	155	3875
56	224	76	400	96	710	116	1250	136	2240	156	4000
57	230	77	412	97	730	117	1285	137	2300	157	4125
58	236	78	425	98	750	118	1320	138	2360	158	4250
59	243	79	437	99	775	119	1360	139	2430	159	4375
60	250	80	450	100	800	120	1400	140	2500	160	4500
61	257	81	462	101	825	121	1450	141	2575	161	4625
62	265	82	475	102	850	122	1500	142	2650	162	4750
63	272	83	487	103	875	123	1550	143	2725	163	4875
64	280	84	500	104	900	124	1600	144	2800	164	5000
65	290	85	515	105	925	125	1650	145	2900	165	5150
66	300	86	530	106	950	126	1700	146	3000	166	5300
67	307	87	545	107	975	127	1750	147	3075	167	5450
68	315	88	560	108	1000	128	1800	148	3150	168	5600
69	325	89	580	109	1030	129	1850	149	3250	169	5800

Tyre Constructions

Cross-ply components	Radial components
The tread consists of specially compounded/vulcanised rubber which can have unique characteristics ranging from wear resistance, cut resistance, heat resistance, low rolling resistance, or any combination of these. The purpose of the tread is to transmit the forces between the rest of the tyre and the ground.
The sidewall is a protective rubber coating on the outer sides of the tyre. It is designed to resist cutting, scuffing, weather checking, and cracking.
The chafer protects the bead and body from chafing (wear from rubbing) where the tyre is in contact with the rim.	The chafer of a radial tire acts as a reinforcement. It increases the overall stiffness of the bead area, which in turn restricts deflection and deformation and increases the durability of the bead area. It also assists the bead in transforming the torque forces from the rim to the radial ply.
The liner is an integral part of all tubeless pneumatic tires. It covers the inside of the tire from bead to bead and prevents the air from escaping through the tire.
The bead of a cross-ply tyre consists of bundles of bronze coated high tensile strength steel wire strands which are insulated with rubber. A cross-ply tyre designed for off-road use typically has two or three bundles. A radial on-road tyre normally only has one. The bead is considered the foundation of the tire. It anchors the bead on the rim.
The cord body is also known as the tyre carcass. It consists of layers of nylon plies. The cord body confines the pressure, which supports the tyre load and absorbs shocks encountered during driving. Each cord in each ply is completely surrounded by resilient rubber. These cords run diagonally to the direction of motion and transmit the forces from the tread down to the bead.	The body ply of a radial tire is made up of a single layer of steel cord wire. The wire runs from bead to bead laterally to the direction of motion (hence the term "radial plies"). The body ply is a primary component restricting the pressure which ultimately carries the load. The body ply also transmits the forces (torque, torsion, etc.) from the belts to the bead and eventually to the rim.
The breakers are also know as belts. They provide protection for the cord body from cutting. They also increase tread stability which resists cutting. Breakers can be made of nylon, aralon, or steel wire.	The belts are layers of steel cord wires located between the tread and the body ply. Off-road tyres can have up to five belts. Road tyres typically have one or two. The steel wire of the belts run diagonally to the direction of motion. The belts increase the rigidity of the tread which increases the cut resistance of the tire. They also transmit the torque forces to the radial ply and restrict tire growth which prevents cutting, cut growth and cracking.

185	65	H	R	13
This is the width in mm of the tyre from sidewall to sidewall when it's unstressed and you're looking at it head on (or top-down). This is known as the section width.	This is the ratio of the height of the tyre sidewall (section height), expressed as a percentage of the width. It is known as the aspect ratio. In this case, 65% of 185mm is 120.25mm - the section height.	This is the speed rating of the tyre.	This tells you that the tyre is a radial construction. Check out tyre construction if you want to know what that means.	This is the diameter in inches of the rim of the wheel that the tyre has been designed to fit on.

185	65	R	13	91	V
Section Width	Aspect Ratio	Radial	Rim Diameter	Load Rating	Speed Rating