4x4 tyres

We tend to take 4x4 tyres for granted but their condition is essential to our safety. When off road, our 4x4 tyres can be the deciding factor as to whether we succeed or fail in our immediate objective.
There are a few important basic points we should be aware of about our tyres regardless of tread pattern or useage.

Tyres should be inflated to the correct pressure for the vehicle and load and checked weekly and before long journeys.

Objects stuck in the tyre tread should be removed as they can cut into a tyre under stress and cause deflation.

Uneven wear on a 4x4 off road tyre can cause steering and vibraton problems. The pattern of wear is indicative of the cause:

- excessive wear on one side.......................wheel alignment needs adjusting
- excessive wear in the tyre centre...............over inflation
- excessive wear on both outer edges...........under inflation
- excessive wear in patches around the tyre...unbalanced wheel
The legal limit for tyre tread depth is 1.6mm over 3/4 of the tyre tread.
Don't have different tyre sizes on the same axle (illegal) and don't mix cross-plies with radials (illegal on the same axle).




Traditional (e.g. 7.50x16)
7.50..........the width of the tyre in inches
16.............the diameter of the wheel rim in inches

Note the ratio of the sidewall to the tread width is typically about 80% for older style tyres.

Modern (e.g.235/85 R16)
235..........the width of the tyre in mm
85............the % ratio of sidewall/height
R.............means the tyre is radial construction
16 ..........the diameter of the wheel rim in inches







Tyre Index Tables
SPEED CATEGORY TABLE
INDEX MAX KPH LI KG LI KG
G 90 N 140 T 190
J 100 P 150 U 200
K 110 Q 160 H 210
L 120 R 170 V 240
M 130 S 180 W 270

LOAD INDEX TABLE
LI KG LI KG LI KG
97 710 107 975 118 1320
97 730 108 1000 119 1360
98 750 109 1030 120 1400
99 775 110 1060 121 1450
100 800 111 1090 122 1500
101 825 112 1120 123 1550
102 850 113 1150 124 1600
103 875 114 1180 125 1650
104 900 115 1215 126 1700
105 925 116 1250 127 1750
106 950 117 1285 128 1800

Edited for your pleasure