Motorcycle Tyre Markings Explained

Those various numbers and markings on a motorcycle tyre sidewall can be confusing initially. This page will explain what those motorcycle tyre markings mean along with weight and speed tables that you can compare the tyre markings on your motorcycle to those in the table charts below.

Tyre Sidewall Markings and Numbers

Let’s take a look at the tyre sidewall markings that are important.

1. Tyre Width

This number denotes the width of the tyre in millimeters from sidewall to sidewall. In this example, it’s 180 mm. The exact width may vary slightly due to manufacturing and tuning characteristics at +/- of 4%.

2. Profile Height

This number is the tyre height and is calculated as a percentage of the tyre width. So in this example, the tyre profile height is 55% of the tyre width (180 mm), making it 99 mm.

3. Speed Rating and Construction

The speed rating of the tyre is represented by the letter ‘Z’ and is rated above 240 kph / 149 mph. Other speed ratings can be found in the table below. The “R” denotes that the tyre is of radial type construction. The other type of tyre construction is ‘cross-ply’ and if the tyre and if this was the case, the ‘R’ would be replaced with a hyphen.

4. Rim Size

The number ’17’ relates to the rim size, so in this instance, it’s 17 inches.

5. Tyre Use

The ‘M/C’ simply means that the tyres intended use is on motorcycles.

6. Load and Speed Indexes

In this example, the number ’73’ informs us that the tyre has a maximum rating of 365 kg at maximum pressure. The the ‘W’ informs us that the tyre has a speed of 168 mph (270 kmh). The top speed is always related to the ‘slowest’ tyre on your motorcycle and if exceeded, risks tyre failure. Always replace a tyre with the same speed ratings so that you do not reduce the capability of your machine. See the chart tables below for all applicable load and speed ratings.

7. Direction of Rotation

The arrow denotes the direction of rotation. If the tyre is placed the wrong way round, your motorcycle will fail the MoT.

8. Tyre Age

Since the year 2000, the production date of any tyre can be found on a sidewall. We see the ‘DOT’ (Department of Transport) code and located at the end are four digits ‘0917’. The first two digits represent the week the tyre was manufactured and the last two digits represent the year. So in this example, the tyre was made in the 9^th week of the year 2017.

Speed Index

The speed index is a rating system denoted by letters located on a tyre sidewall. The speed rating of each tyre is the maximum speed in which a tyre can sustain under load, indicated by its load index and under specific conditions detailed by the manufacturer.

If possible fit tyres to your motorcycle with identical speed ratings. Using a tyre with a lower speed rating can run the risk of invalidating your insurance policy.

Rating	Km/h	Mph
B	50	30
C	60	37
D	65	40
E	70	43
F	80	50
G	90	56
J	100	62
K	110	69
L	120	75
M	130	81
N	140	87
P	150	95
Q	160	100
R	170	105
S	180	113
T	190	118
U	200	125
H	210	130
V	240	150
W	270	168
Y	300	186
ZR	240+	150+

Load Index

The load index is numerical code rating system that corresponds to the maximum weight that a tyre can support at the speed indicated by its speed rating and under specific conditions detailed by the manufacturer. The load index number can be located on the sidewall of your tyre.

Index	Kg	Index	Kg
20	80	60	250
21	82.5	61	257
22	85	62	265
23	87.5	63	272
24	90	64	280
25	92.5	65	290
26	95	66	300
27	97.5	67	307
28	100	68	315
29	103	69	325
30	106	70	335
31	109	71	345
32	112	72	355
33	115	73	365
34	118	74	375
35	121	75	387
36	125	76	400
37	128	77	412
38	132	78	425
39	136	79	437
40	140	80	450
41	145	81	462
42	150	82	475
43	155	83	487
44	160	84	500
45	165	85	515
46	170	86	530
47	175	87	545
48	180	88	560
49	185	89	580
50	190	90	600
51	195	91	615
52	200	92	630
53	206	93	650
54	212	94	670
55	218	95	690
56	224	96	710
57	230	97	730
58	236	98	750
59	243	99	775
60	250	100	800