A-C Tyres (UK) Limited Mount Pleasant Ind Estate, Cross Street, Oldham, OL4 1HD 0161 624 4138
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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 A-C Tyres (UK) Limited on 0161 624 4138.