QUALITY RATINGS

UTQG

UTQG stands for ‘Uniform Tire Quality Grading’. You may have noticed markings on the sidewall of your tyres for Treadwear, Traction and Temperature; these are UTQG ratings.

The UTQG ratings originated in America to allow consumers to easily compare the treadwear, traction and temperature capabilities of their tyres.

All SUV light duty construction and passenger tyres sold in America must, by law, have these ratings marked on the sidewall. Some tyres sold in South Africa do not carry the UTQG ratings so you may not have the information to compare a Cooper tyre to your current tyre’s quality.

TREADWEAR

Treadwear grades are an indication of a tyre’s wear rate. The higher the treadwear number, the longer it takes for the tread to wear down.

Treadwear grades are tested under controlled conditions using four vehicles fitted with test tyres that run in convoy. The vehicles repeatedly run a specified 640km road course for a total of 11,520km. Tread depths are measured every 1,280km and the measurements are averaged to give a projected wear-out life.

A ‘standard’ control tyre is assigned a grade of 100 and the treadwear rates of all test tyres are compared to it. For example, a tyre grade of 200 should take twice as long as the control tyre to wear out.

TRACTION

Traction grades are an indication of a tyre’s ability to stop in the wet. A higher grade should allow your vehicle to stop on wet roads in a shorter distance than a tyre with a lower grade.

Traction is graded from highest to lowest as AA, A, B and C.

TEMPERATURE

Temperature grades are an indication of a tyre’s resistance to heat. Sustained high temperatures (for example, driving long distances in hot weather), can cause a tyre to deteriorate, leading to blowouts and tread separation.

EU tyre ratings

The EU tyre ratings are intended to give consumers more information on important safety and environmental information when choosing new tyres. It helps to compare tyres for wet grip, fuel efficiency and noise.

Load Index and Speed Ratings

The Load Index is a numerical code associated with the maximum load a tyre can carry at the speed indicated by its Speed Category symbol under specified conditions up to 210km/h.

Using a 265/75R16 123Q tyre size as an example, the 123Q at the end of the size represents the tyre’s service description. A service description identifies the tyre’s load index and speed rating. The first three digits - 123 - represent the tyre’s load index and are followed by a single letter - Q - identifying the tyre’s speed rating.

Load Index

265/75R16 123Q - The Load Index - 123 - is the tyre’s assigned numerical value used to compare relative load-carrying capabilities. In the case of this example, the 123 identifies the tyre’s ability to carry a maximum of 1550 kg (3417 lbs). The higher the tyre’s Load Index number, the greater its load-carrying capacity. The Load Index rating also represents the load-carrying capacity of the tyres when they are inflated to maximum PSI so the load-carrying capacity reduces as tyre pressures are reduced.

Load Index	kg	Load Index	kg	Load Index	kg	Load Index	kg
60	250	90	600	120	1400	150	3350
61	257	91	615	121	1450	151	3450
62	265	92	630	122	1500	152	3550
63	272	93	650	123	1550	153	3650
64	280	94	670	124	1600	154	3750
65	290	95	690	125	1650	155	3875
66	300	96	710	126	1700	156	4000
67	307	97	730	127	1750	157	4125
68	315	98	750	128	1800	158	4250
69	325	99	775	129	1850	159	4375
70	335	100	800	130	1900	160	4500
71	345	101	825	131	1950	161	4625
72	355	102	850	132	2000	162	4750
73	365	103	875	133	2060	163	4875
74	375	104	900	134	2120	164	5000
75	387	105	925	135	2180	165	5150
76	400	106	950	136	2240	166	5300
77	412	107	975	137	2300	167	5450
78	425	108	1000	138	2360	168	5600
79	437	109	1030	139	2430	169	5800
80	450	110	1060	140	2500	170	6000
81	462	111	1090	141	2575	171	6150
82	475	112	1120	142	2650	172	6300
83	487	113	1150	143	2725	173	6500
84	500	114	1180	144	2800	174	6700
85	515	115	1215	145	2900	175	6900
86	530	116	1250	146	3000	176	7100
87	545	117	1285	147	3075	177	7300
88	560	118	1320	148	3150	178	7500
89	580	119	1360	149	3250	179	7750

Speed Ratings

Speed ratings are based on laboratory tests where the tyre is pressed against a large diameter metal drum to reflect its appropriate load, and run at (ever-increasing) speeds until the tyre’s required speed has been consistently exceeded.

It is important to note that speed ratings only apply to tyres that have not been damaged, altered, under-inflated or overloaded. A tyre that has been cut or punctured no longer retains the original speed rating, even after being repaired.

Speed Category Symbol	Speed km/h	Speed Category Symbol	Speed km/h
L	120	T	190
M	130	U	200
N	140	H	210
P	150	V	240
Q	160	W	270
R	170	Y	300
S	180	Z	Over 240

PLY RATINGS VS LOAD RANGE

Load capacity

It is not the tyre that carries the load, but the air inside it. The tyre contains the air. To carry more load you require more air. The best way to increase load capacity is to use a bigger tyre or a tyre that can run at a higher inflation pressure. The tyre needs to be strong enough to handle the higher capacity. The traditional ways to define this are Ply rating and Load Range.

The load range/ply rating is branded on a tyre’s sidewall and identifies how much load the tyre is designed to carry at its industry specified pressure.

What is “Ply Rating?”

In the days of bias tyres, casing strength was built up by adding layer upon layer of cotton fabric. The layers were placed with the thread in each layer at an angle to each other. That added strength, because the tensions would be distributed throughout the layers of fabric. The Ply Rating used to refer to the number of layers of cotton.

Cotton was discontinued in tyres a long time ago. One of the major improvements was making plies out of nylon. Nylon is so much stronger that tyres were stamped with the words, “2 Ply/4 Ply Rating.” That meant there were only two nylon plies, but they were so strong the tyre was equivalent to one made of four cotton plies.

Ply materials continued to improve, especially with the introduction of steel ply materials and radial construction, making the old Ply Number less and less meaningful. And that resulted in the newer designation we use today, called “Load Range.”

What is “Load Range?”

It’s no longer the number of plies. What is different today is the strength of the steel cables in those plies or the number of cables per inch. Tyre manufacturers are now at the point where instead of adding more plies the strength of the casing is adjusted to achieve the desired load capacity.

The Load Range is depicted on the tyre by an alphabetical symbol which equates tyre thickness to a comparable ply rating.

Load Range	Ply Rating
C	6
D	8
E	10