Authored by: Tractor tyre expert | 03 November 2023
The efficiency of an agricultural tractor depends essentially on its tyres. How they perform is crucial in getting the job done optimally. However, tyres wear over time and with use. They have to cope with many demands and are placed under strain during your different campaigns or trips on the road.
It is therefore important to check them regularly and make sure they are correctly maintained, to optimise their lifespan and their efficiency. A good understanding of the process of wear is essential if you wish to improve the tyre’s useful life.
Wear to your agricultural tyres may be considered normal if the reduction in the height of the lugs is even over the entire width of the tread over time. This wear is inevitable and depends on the type of ground, the type of crops, the type of work, the load, the speed, the slip ratio, etc.
On the other hand, there are cases of abnormal wear which are often the sign of an incorrect setting or the wrong use of the tyre. This wear may affect tyre performance, safety and your return on investment. It is therefore essential to spot the wear and correct the problem as quick as possible.
Here are a few examples of abnormal wear and the possible causes:
This takes the form of more marked wear on the inner side of the right tyre and the outer side of the left tyre (or the other way round) It may be due to driving very frequently on sloping land, to an inflation pressure that is too low, to mechanical wear (steering pivot pins or bearings) or incorrect steering settings.
To rectify this, you will need to adapt pressure, check the parallelism and geometry of the axles and swap the tyres around if the wear is too marked.
This results in wear that is more pronounced at the centre of the tyre. It may be caused by inflation pressure that is too high, meaning that the centre of the tread has to bear the load alone.
To rectify this, inflation pressure must be adapted based on the load, the type of work and the type of ground.
this comes in the form of more accentuated wear on the inside or outside of the tyre. It can be caused by incorrect camber, which is a vertical angle of the wheels that is not perpendicular to the ground, or mechanical wear (steering pivot pins or bearings).
To correct this, the camber must be checked and corrected if necessary, or the faulty mechanical parts replaced.
This type of wear will rapidly reduce the lifespan of your tyres and takes the form of many fissures and chipping of the rubber particles on the tyre lugs. It can be caused by highly abrasive soils or stoney ground which attacks the tyre’s rubber. To remedy this, the slip ratio must be limited to between 8% and 12%. If you know the exact load per axle, you can adapt inflation pressure accordingly, which will allow you to reduce slip.
When you replace your tyres, you could opt for a tyre model made of more resistant rubber.
There is no universal rule to determine the ideal moment to change your agricultural tyres. It will depend on your use, your needs and your priorities. However, there are a few indicators which can help you make your decision.
Most tyre manufacturers recommend changing your tyres when you reach a level of 75% wear to the lugs, i.e. when the tyre lugs are one quarter of what they were on your new tyre. This level of wear corresponds to a significant loss of efficiency, especially in terms of traction and above all on wet soil.
The loss of grip will increase your fuel consumption as well as your working time, the quality of your work will decline (soil compaction due to excessive slip).
If you use your tractor essentially in the fields, it may be wise to change your tyres at this level of wear, to avoid losing out in terms of efficiency and safety. If you use your tractor essentially on the road, you can wait a little longer, up to 90% wear, to really get the most from your tyres. But beware, beyond this level you may compromise your tractor’s road handling and braking capacity.
To measure the level of wear to your tyres, you can use a measuring device or gauge to measure the depth of the lug, which you can obtain from your tyre dealer or manufacturer.
There are many factors that have an influence on agricultural tyre wear. Among the most important are:
Hard, abrasive or stoney soil is more aggressive for tyres than softer clay or sandy soils. It causes cuts, flaking and more rapid wear to the lugs. Sloping land requires more traction, which also increases the level of wear.
Each tyre model was designed by the manufacturer with a precise work objective. If you don’t use the tyre for this objective, by driving on unsuitable land, at too high a speed, with sudden accelerations or sharp braking, then the wear life of your tyres will be limited. This excessively harsh use of your tyres will lead to more pronounced wear due to the deformation and overheating of the rubber.
Crops which require frequent comings and goings, work involving heavy loads or repeated manœuvres are more demanding on tyres than activities which necessitate less intervention. They result in more pronounced wear due to the rubbing and twisting of the lugs.
Inflation pressure is an essential aspect in terms of tyre wear. Too little or too much pressure for the type of work and soil can lead to rapid wear, loss of traction and extra fuel consumption, a deterioration of the casing and an increased risk of punctures.
Certain agricultural activities are particularly testing for tyres. These include:
This involves heavy loads which vary depending on the work and therefore an inflation pressure that is often unsuitable for the actual weight on the tyres (harvesting, spraying). These variations in load place great strain on the casing and tyre tread.
This requires a high level of traction and torque, which is very demanding on the tyre lugs. An inflation pressure adapted to the type of soil is also required to avoid compaction and erosion.
Unlike car tyres, agricultural tyres are more suitable for work in the fields on soft ground. The road surface is made of very hard, abrasive micro particles. With speed, which is high on the road, the effect of the wear accelerates, reducing the lifespan of the tyres. Frequent transport necessitates high pressure settings which are more suitable for the road, to reduce wear and optimise comfort and braking.
The use of the tractor for construction or landscaping work will have an impact on wear at the level of the tread and the casing due to the presence of lots of stones, rubble or debris on this type of work site.
To manage and anticipate agricultural tyre wear better, there are a few simple practices to adopt:
The lifespan of your agricultural tyres is not only linked to their strength and quality. Your ability to spot signs of wear, to understand the origin and adopt a suitable use and conduct is crucial in increasing their wear life.
By controlling these aspects, not only do you optimise your operating costs by delaying the replacement of the tyres, you also contribute to better tractor efficiency, lower fuel consumption and the protection of your soil.
Let’s not forget that the tyre is the direct interface between tractor and ground: protecting it leads to savings, but also makes sure the work carried out is more efficient and respectful of the environment.
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