Resources for Drivers and Operators

Tyre marks explained

Commercial vehicle tyres have two main types of markings on their sidewalls in addition to the manufacturer's own marks.

Tyre size markings on commercial tyres

Tyre size markings include references to the following information:

The section width of the tyre (either in inches of millimetres).
There is often an optional reference to the 'aspect ratio' of the tyre - that is a ratio of the tyre's height compared to its width.
The types of tyre construction - 'R' for radial.
The wheel rim diameter in inches.

Figure 1.
11R22.5
11 = 11 inches section width
R = radial construction
22.5 = rim diameter 22.5 inches

Figure 1.

Figure 2.
295/80R22.5
295 = 295mm section width
80 = low profile tyre – section height 80% of its section width
R = radial construction
22.5 = rim diameter 22.5 inches

Figure 2.

Load and speed markings on commercial tyres

These inter-related markings are always shown together. They are known as the 'Load Index' and the 'Speed Rating Symbol', and reference the following information:

Load index is a numerical code which shows the maximum load a single tyre can carry at the speed shown by it Speed Rating Symbol.
There is often an optional reference which shows the load a twinned pair of tyres can carry at the speed shown by it Speed Rating Symbol.
The Speed Rating Symbol indicates the speed at which the tyre can carry a load shown by the Load Index.

Figure 3.
112/110M
112 = Load index for single tyres (1120 kg - see Load Index key below)
110 = Load index for twinned tyres (1060 kg - see Load Index key below)
M = Speed rating (130 KPH / 81 MPH max speed at load as in Load Index - see Speed rating key below)

Figure 3.

Figure 1.

Figure 2.

Figure 3.

Commercial vehicle tyre maximum load by Load Index number (L.I.) Key

L.I.	kg	L.I.	kg	L.I.	kg	L.I.	kg	L.I.	kg	L.I.	kg	L.I.	kg
0	45	40	140	80	450	120	1400	160	4500	200	14000	240	45000
1	46.2	41	145	81	462	121	1450	161	4625	201	14500	241	46250
2	47.5	42	150	82	475	122	1500	162	4750	202	15000	242	47500
3	48.3	43	155	83	487	123	1550	163	4875	203	15500	243	48750
4	50	44	160	84	500	124	1600	164	5000	204	16000	244	50000
5	51.5	45	165	85	515	125	1650	165	5150	205	16500	245	51500
6	53	46	170	86	530	126	1700	166	5300	206	17000	246	53000
7	54.5	47	175	87	545	127	1750	167	5450	207	17500	247	54500
8	56	48	180	88	560	128	1800	168	5600	208	18000	248	56000
9	58	49	185	89	580	129	1850	169	5800	209	18500	249	58000
10	60	50	190	90	600	130	1900	173	6000	210	19000	250	60000
11	61.5	51	195	91	615	131	1950	171	6150	211	19500	251	61500
12	63	52	200	92	630	132	200	172	6300	212	20000	252	63000
13	65	53	206	93	650	133	2060	173	6500	213	20600	253	65000
14	67	54	212	94	670	134	2120	174	6700	214	21200	254	67000
15	69	55	218	95	690	135	2180	175	6900	215	21800	255	69000
16	71	56	224	96	710	136	2240	176	7100	216	22400	256	71000
17	73	57	230	97	730	137	2300	177	7300	217	23000	257	73000
18	75	58	236	98	750	138	2360	178	7500	218	23600	258	75000
19	77.5	59	243	99	775	139	2430	179	7750	219	24300	259	77500
20	80	60	250	100	800	140	2500	180	8000	220	25000	260	80000
21	82.5	61	257	101	825	141	2575	181	8250	221	25750	261	82500
22	85	62	265	102	850	142	2650	182	8500	222	26500	262	85000
23	87.5	63	272	103	875	143	5725	183	8750	223	27250	263	87500
24	90	64	280	104	900	144	2800	184	9000	224	28000	264	90000
25	92.5	65	290	105	925	145	2900	185	9250	225	29000	265	92500
26	95	66	300	106	950	146	3000	186	9500	226	30000	266	95000
27	97.5	67	307	107	975	147	3075	187	9750	227	30750	267	97500
28	100	68	315	108	1000	148	3150	188	10000	228	31500	268	100000
29	103	69	325	109	1030	149	3250	189	10300	229	32500	269	103000
30	106	70	335	110	1060	150	3350	190	10600	230	33500	270	106000
31	109	71	345	111	1090	151	3450	191	10900	231	34500	271	109000
32	112	72	355	112	1120	152	3550	192	11200	232	35500	272	112000
33	115	73	365	113	1150	153	3650	193	11500	233	36500	273	115000
34	118	74	375	114	1180	154	3750	194	11800	234	37500	274	118000
35	121	75	387	115	1215	155	3875	195	12150	235	38750	275	121000
36	125	76	400	116	1250	156	4000	196	12500	236	40000	276	125000
37	128	77	412	117	1285	157	4125	197	12850	237	41250	277	128500
38	132	78	425	118	1320	158	4250	198	13200	238	42500	278	132000
39	136	79	437	119	1360	159	4375	199	13600	239	43750	279	136000

Commercial vehicle tyre Speed Ratings

Speed Rating Symbol	KPH	MPH
E	70	43
F	80	49
G	90	56
J	100	62
K	110	68
L	120	75
M	130	81
N	140	87
P	150	93
Q	160	99
R	170	105
S	180	112