Motocross Motorcycle Tyres
Motorbike riders understand that their motorcycle is far more than a vehicle for getting from A to B. It is also a machine that can take them on wild and exciting adventures. The lure of off-road motorbiking is irresistible for many riders but as with anything related to the unique experience of the motorcycle, safety and performance are vital concerns. However grand your ambitions and however fearless you may be, having the correct tyres in every situation is a must.
1) What are Motocross Motorcycle Tyres?
If you are planning to undertake any off-road riding on your motorcycle, then motocross tyres will be an essential part of your kit. They are specifically made for optimum performance, safety and comfort across a variety of off-road terrains, from dirt tracks to the most extreme endurance courses.
It is important to remember that motocross tyres are made for off-roading and dirt-bike riding. This means that although they are excellent choices for these pursuits, they are unlikely to meet the legal requirements of ordinary road use. Road legal tyres must comply with Regulation 30 of the Economic Commission for Europe of the United Nations (UN/ECE). Compliant tyres will have an E mark on the sidewall. Motocross tyres carry the letters ‘NHS’ which means Not for Highway Services. Some manufacturers do produce motocross tyres that can be used legally on public roads, but you need to make absolutely sure.
The specifications of motocross tyres are designed to give them grip, traction and stability on soft, medium and hard surfaces. They can cope with rock, gravel and desert sand just as easily as they will cut through mud and clay. Their special tread profile allows them to adapt to all kinds of surfaces. However, although there are no all-purpose motocross tyres and no single perfect tyre, across the range that is available you will always be able find a tyre that best suits the kind of off-roading you plan to do.
2) How to choose the best Motocross Motorcycle Tyres for your usage
To begin with, you should familiarise yourself with the terminology of motocross tyres. One of the first things you’ll notice is that the tyres are classified as hard, medium and soft. This describes the terrain for which they are built. It does not describe the compound from which the tyre is made. In fact, the softest motocross tyres suit the hardest of terrains while the hardest are best on the softest ground.
As different terrains demand different tyres let’s look at the different conditions and the options available.
Hard terrains are typically those which feature rocky tracks and inclines. The ground is very solid so even when wet, there is no need to worry about changes in resistance, although wet rock can of course be much more slippery than dry. What you are looking for on this kind of surface is a hard terrain tyre made from a soft and flexible compound which will absorb any shocks and jolts. In addition, it will give excellent traction on unyielding dry rock and potentially treacherous wet rock.
Motocross tyres made for soft terrain will have widely spaced tread patterns. They are usually made from very firm rubber so that their characteristically tall lugs can keep their shape. Soft terrain is as it sounds – anything loose, damp and without much structure or resistance. This will include loamy and boggy stretches of ground as well as sand and loose gravel.
Medium terrain tyres, also described as intermediate, are a compromise between the extremes of hard and soft. Inevitably their performance on the hardest and softest of ground will be inferior to that of the tyres geared entirely for those conditions but the convenience value often outweighs that disadvantage. Instead of having to keep duplicate sets of rims which you’ll need to change every time you switch between hard and soft, medium terrain tyres will give you an entirely acceptable performance in all conditions. They might not always be of competition-winning level but they will certainly give you a great ride.
3) Sizing
There are three measures of size in common use: metric, alpha and imperial. It may be necessary to convert between the three in order to make sure you have the correct size. A retro MX motorcycle is likely to use inches (imperial) in its manual but if you follow this simple example you won’t go wrong. Let’s take a tyre classed as 90/90-21. The first number is the width, so 90mm. The second number is the height as a percentage of the width, so 90% of 90 equals 81mm in height. The third number is the wheel’s diameter in inches, so here 21 inches. In Alpha measurements a 90/90 is designated as an MJ90 and in Imperial as a 2.75/3.00
4) Motocross Motorcycle Tyre Load Index
The table below gives you the load index which is a numerical code telling you the maximum weight that a tyre is able to support. The load of the tyre when multiplied by 2 should cover the gross single axle load of the motorcycle. You will find your tyre’s load index on the sidewall. Using the table you can determine the load bearing capacity of your tyres.
Weights are in kilograms.
Load index | Weight |
---|---|
20 | 80 |
22 | 85 |
24 | 85 |
26 | 90 |
28 | 100 |
30 | 106 |
31 | 109 |
33 | 115 |
35 | 121 |
37 | 128 |
40 | 136 |
41 | 145 |
42 | 150 |
44 | 160 |
46 | 170 |
47 | 175 |
48 | 180 |
50 | 190 |
51 | 195 |
52 | 200 |
53 | 206 |
54 | 212 |
Load index | Weight |
---|---|
55 | 218 |
58 | 236 |
59 | 243 |
60 | 250 |
61 | 257 |
62 | 265 |
63 | 272 |
64 | 280 |
65 | 290 |
66 | 300 |
67 | 307 |
68 | 315 |
69 | 325 |
70 | 335 |
71 | 345 |
72 | 355 |
73 | 365 |
74 | 375 |
75 | 387 |
76 | 400 |
77 | 412 |
78 | 425 |
Load index | Weight |
---|---|
79 | 437 |
80 | 450 |
81 | 462 |
82 | 475 |
83 | 487 |
84 | 500 |
85 | 515 |
86 | 530 |
87 | 545 |
88 | 560 |
89 | 580 |
90 | 600 |
91 | 615 |
92 | 630 |
93 | 650 |
94 | 670 |
95 | 690 |
96 | 710 |
97 | 730 |
98 | 750 |
99 | 775 |
100 | 800 |
Load index | Weight |
---|---|
101 | 825 |
102 | 850 |
103 | 875 |
104 | 900 |
105 | 925 |
106 | 950 |
107 | 975 |
108 | 1000 |
109 | 1030 |
110 | 1060 |
111 | 1090 |
112 | 1120 |
113 | 1150 |
114 | 1180 |
115 | 1215 |
116 | 1250 |
117 | 1285 |
118 | 1320 |
119 | 1360 |
120 | 1400 |
5) Motocross Motorcycle Tyre Speed Index
This table shows the letter code which denotes the maximum speed that a tyre can sustain. You’ll find the code on the sidewall of your tyre and you can use the table to determine your tyre’s maximum speed capability.
Speed index | Speed km/h |
---|---|
A1 | 5 |
A2 | 10 |
A3 | 15 |
A4 | 20 |
A5 | 25 |
A6 | 30 |
A7 | 35 |
A8 | 40 |
B | 50 |
C | 60 |
Speed index | Speed km/h |
---|---|
D | 65 |
E | 70 |
F | 80 |
G | 90 |
J | 100 |
K | 110 |
L | 120 |
M | 130 |
N | 140 |
P | 150 |
Speed index | Speed km/h |
---|---|
Q | 160 |
R | 170 |
S | 180 |
T | 190 |
U | 200 |
H | 210 |
V | 240 |
ZR | >240 |
W | 270 |
Y | 300 |
6) Next Steps
We supply a comprehensive range of motocross motorcycle tyres with the perfect options for all conditions. We prioritise safety but not at the expense of performance. The tyres we stock have been carefully selected for their high-specification, durability and reliability. Picking the right tyre for the terrain is crucial and if there is any doubt we are able to advise on the best solution.
The information we have covered here should cover all the basics along with details of optimum tyre load and speeds. The owner’s manuals for individual motorcycles will disclose more information and the motorcycle’s VRN will also help to identify specific requirements. If further questions arise please contact Autotyres (Shrewsbury) Limited on 01743 232130.