The use of proper inflation pressure is the most important factor contributing to the satisfactory performance and maintenance of tractor and implement tyres. Correct inflation pressure can be determined by weighing the loaded axle (i.e. rear tractor axle with implement in raised position) and then referring to the load/inflation tables shown for the tyre size. All tables give load per tyre.
- Underinflation - Can cause damage to the cord body of the tyre. The continued abnormal flexing of the tyre causes premature failure of the tyre carcass.
- Overinflation - Should be avoided except for hillside ploughing and when the tractor is required to operate on hard surfaces for any length of time.
- Check Inflation Pressures Frequently - Inflation pressures should be checked regularly (at least every two weeks). For accurate inflation use a special low pressure gauge which should be checked for accuracy at least once a year. A special gauge is required for testing tyres filled with water or antifreeze solutions. To determine the true operating pressure for water inflated tyres; the valve should be at the bottom of the tyre. Tyres should be tested when they are cold and before the tractor is put into operation. A tyre that appears to have sufficient pressure when it is hot will be underinflated when it cools.
- Road Versus Field Applications - Road and field work require different inflation pressures. Make sure that all times, the inflation pressures are adjusted according to the work conditions.
Use of Recommended Rims
The use of rims narrower than the recommended brings potential mounting problems because the rim shield or flange cover molded into most tyre designs tends to interfere with the seating of the tyre beads on a narrow rim. Once mounted on a narrow rim, the tyre rim shield applies undue pressure on the rim flange, with possible tyre sidewall separation or premature rim failure at heel radius.
On a narrow rim the tread is rounded. As with overinflation tyre treadwear will be concentrated in the centre area of the tread and traction in the field will be reduced. Always use the recommend rim.
Tractor tyres with insufficient wheel weights or excessive inflation pressure will wear the tread bars smooth or will snag and cut the bars when subjected to tyre spinning on abrasive surfaces. Addition of weights, adjustment of inflation pressure to recommendations, decreasing of draft load and proper operation will remedy this condition.
Tyres should be inspected for possible damage, particularly cuts or breaks that enter into or expose cords in the carcass. Damaged tyres should be removed promptly from the wheel and sent to a reputable tractor tyre services station for full internal inspection and if possible permanent repairs.
When valves are torn off the tubes, it indicates a slippage of the tyre bead on the rim or an improper centring of the valve rim. Slippage of the tyre bead on the rim may be caused by:
- Low inflation pressure.
- Improper seating of the bead on the rim.
- Excessive use of a lubricant on the bead or rim when mounting the tyre.
- Run below tolerance.
Grease and Oil
To avoid damage of the rubber, do not allow tyres to come into contact with grease or oil. After using the tractor in spraying operations, wash any chemicals from the tyres.
Tyre Construction Mixing
Mixing radial and bias tyres on the same axle should be avoided at all times.