Inflation pressures should be checked at least on a weekly basis. Recommended inflation pressures based on total load on tyres should be used. For accurate inflation, use a special low-pressure gauge with 10 kPa graduations. Gauges should be checked occasionally for accuracy. Always use sealing valve caps to prevent loss of air.
Tyre overload or under-inflation have the same effect of over-deflecting the tyre. Under such conditions the tread on the tyre will wear rapidly and unevenly, particularly in the shoulder area. Radial cracking in the upper sidewall area will be a problem.
With under-inflated drive tyres in high torque applications, sidewall buckles will develop, leading to carcass breaks in the sidewall.
While an under-inflated drive tyre may pull better in some soil conditions, this is not generally true and not worth the high risk of tyre damage that such an operation invites.
Over-inflation results in an under-deflected tyre carcass. The tread is more rounded, concentrating tread wear in the centreline area. Traction is reduced in high torque service because ground contact of the tread shoulder area is reduced and the harder carcass - with reduced flexing characteristics - does not work as efficiently. In addition, the tightly stretched over-inflated carcass is more subject to weather checking and impact break damage.
More tyres go out of service prematurely from under-inflation than for any other reason.
Correct inflation - On the road:
Over inflation - On the road:
Wear is produced at the centre end of the bars. The front edges of the bars become round.
Under inflation - On the road:
Excessive deflection gives heel and toe type wear, increasing towards the centreline.