Wear is generally the main reason for having to change your agricultural tyres, which represents a considerable cost for your farm.
Just like all parts that wear, the speed at which your tyres deteriorate depends on their level of quality, but also and above all on your use of them: rare or frequent, on hard ground, in the fields, on the road, etc.
By following a certain number of basic rules, you can slow down wear and put off replacing your tractor tyres for longer.
There are 5 essential points to know to gain more than a year’s extra use of your tractor tyres. This article presents the 5 points which will help you make savings:
1. Adapt agricultural tyre pressure more often
There is no average pressure at which you can do everything, carry excessive loads, drive fast, not take account of the type of ground, etc.
Many farmers tend to increase the inflation pressure in their tyres as a precaution, to avoid having to check tyre pressure based on load in order to save time.
Even though overinflation may help reduce the crushing of the tyres, it can lead to premature wear in certain conditions.
Wear linked to overinflation and use on the road
Practically speaking, an overinflated tyre is more rigid, which is more suitable for the road. In the fields, it will have a reduced contact patch with the ground, which will reduce its traction capacity and is likely to increase rolling resistance, the risk of slippage and compression leading to soil compaction: In the long term, this will considerably reduce the production capacity.
There is a major risk of rapid wear with high inflation pressure:
- The high pressure within the tyre globally corresponds to the pressure exerted on the ground; the higher the pressure, the more the tyre sinks into the loose soil in your fields, especially in wet conditions. Deep tilling will lead to excessive slippage and result in rapid wear to the tread.
- On the road, an overinflated tyre will bulge in the middle, reducing contact with the ground to the centre of the tread, which is likely to lead to faster, more marked wear on the central part of the tyre.
There are different drawbacks to driving with under inflated tyres, but this may also lead to excessive wear.
Opting for a pressure of up to 0.4 bar less than the manufacturer recommendations to avoid soil compaction can also cause wear to the tyre. If you choose to do this, you must imperatively establish the overall payload and adapt travelling speed accordingly.
What types of wear are linked to an underinflated tyre:
- When driving, an under inflated tyre tends to flatten out into a characteristic form. The casing deflects excessively at the level of the sidewalls and the tyre cannot regain its original shape. This leads to a rise in internal temperature, the structure of the tyre deteriorates progressively and irreversibly, which may lead to a sudden puncture or break in the casing. Although the wear does not appear immediately, it may become visible later, even after the inflation pressure has been adjusted.
- The tyre’s lifespan will be reduced by 25% if you drive frequently on the road with under inflated tyres, especially because this type of surface is highly abrasive. The tyre effectively overheats, making the rubber more supple and therefore more vulnerable to wear.
Ideally, you should adjust inflation pressure based on the load, the working area and the type of ground.
2. Reduce the load so as not to overexert the tyres
During harvesting and silage periods, agricultural tyres are placed under a great deal of strain and will wear rapidly. They effectively have to bear heavy loads, in particular the weight of the tractor, the different implements or trailers and the fruit of the harvest.
This type of load increases the strain placed on the tread and the casing of the tyres, which, in the long term, may lead to permanent deformation.
To limit tyre wear linked to load, there are a few good practices that you can adopt:
Spread the load more evenly whenever possible
If you use a trailer with several axles, make sure that the harvest is well distributed in the tipper so that the load is evenly spread over the different axles.
This will make the tyre wear even and increase the lifespan.
Choose the right tyre size
It is crucial, when buying, to choose the right tyres. To avoid premature wear and guarantee your tyres’ resistance, make sure that your tyre size and load index correspond to your maximum loads including implements and trailers.
In any case, try not to overload your tyres by reducing the quantities transported whenever possible.
Swap your tyres over
When your right tyres wear faster than your left tyres, or the other way around, you can swap them over, on condition that this is not caused by a mechanical problem (misalignment or mounting error).
Swapping your tyres around may be an interesting way to optimise wear over a longer period of time. This is particularly useful for the front wheels of a tractor.
3. Reduce speed on the road
Although quality agricultural tyres are made to cope with extreme conditions on the road and in the fields, they do have a limited lifespan.
In addition to pressure and load, their lifespan also depends on the speed at which they travel.
Speed has a major influence on wear, which is directly linked to the resistance of your tyre’s rubber.
If you want to use your tyres for longer, the best advice we can give you is to:
- Reduce speed on the road in general.
- Always respect the speed and load index indicated on the tyre’s sidewall.
To have a good understanding of this speed index, you simply need to refer to the manufacturer’s speed rating chart supplied with your equipment upon purchase.
By driving too frequently at a higher speed than recommended by the manufacturer, you could rapidly damage the layer of rubber which makes up your tyre’s tread.
This wear will be even more rapid if you drive too fast on the road with a heavy load.
Speed associated with compression caused by the load effectively leads to overheating of the internal structure of the tyre, with temperatures potentially reaching 60 degrees or more. It is therefore highly advisable to reduce speed to limit heating and the deterioration of your casing.
4. Check the mechanical condition of the tractor
LGeometry problems are among the most frequent causes of agricultural tyre wear. This type of problem is linked to the different types of strain imposed on your tyres during use.
The angle settings to be checked are:
- between the four tyres and the road,
- between the tyres and the tractor,
- incorrect adjustment between the tyres themselves.
Check the parallelism
Parallelism corresponds to the angle between the axis of the wheel and the direction of travel. Ideally, your tyres should be perfectly parallel to the tractor, otherwise you could wear the exterior of the tyre rapidly (toe-in) or the interior (toe-out).
A maximum toe-out angle of 1 to 1.5 mm is recommended, in order to offset the mechanical strain linked to the tractive force sustained by the front axle when in four-wheel drive.
- In the case of toe-in: the wear is more marked on the exterior right side of the tyre.
- In the case of toe-out: predominant wear can be seen on the inside right of the tyre, generally because of the crowned road shape.
Camber is the tilt of the wheels compared to a vertical position. When you adjust camber, your wheels should be as flat as possible on the ground to avoid damaging them rapidly.
- Positive camber: when the top of the wheel tilts outwards. In this case, the wear appears on the exterior side of the tyre.
- Negative camber: when the top of the wheel tilts inwards. In this case, the wear appears on the interior edge of the tyre.
Adjust the lead ratio
The lead ratio is the number of rotations the smaller front tyres make in relation to the larger rear tyres on four-wheel drive tractors.
It enables the synchronisation of the front and rear axles of the tractor.
It has to be correct to avoid your tyres wearing rapidly, given that an incorrect lead ratio results in premature wear to the two front tyres compared to the rear tyres or the other way around.
The wrong lead ratio also results in wear to the mechanical parts.
To keep your tyres longer, you must choose a tyre size that ensures the right amount of lead so that the tractive force is slightly higher at the front than at the rear, with the front axle pulling slightly more.
- If the lead ratio is above 4 or 5%, the rear axle slows down the front axle, meaning that the front axle undergoes a high level of mechanical strain, thus causing wear to the front tyres.
- If the lead ratio is 0% or below (lag), the rear axle pushes the front axle too much, causing excess slippage at the rear and making the front axle less efficient. If you keep driving in these conditions, in addition to tyre wear, you are likely to damage your tractor’s gear box.
5. Be careful of how you use your tyres
Among the different factors which could lead to the premature wear of your agricultural tyres, your daily use is decisive.
If you have chosen low-pressure tyres designed for work in the fields and you use them in a quarry or forest area, this will considerably accelerate the rate of wear in addition to the risk of even bigger problems. You must not consider the tyres’ robustness as a guarantee that they will withstand all possible uses.
Too frequent use on the road
Unlike car or motorbike tyres, agricultural tyres are not designed for the road, but principally for use in the fields. Unfortunately, farms have plots of land that are increasingly far away, which means that tractors are obliged to make long trips by road to reach the fields or transport harvests.
Several factors may lead to rapid wear to your tyres when you drive on the road:
- Tiny irregularities in the ground: a dry asphalt road is an extremely hard and abrasive surface. The rubber deflects to take on the shape of the road surfacing which, with the speed, acts like sandpaper and wears down the tips of the lugs. Reducing speed will limit this problem.
- The state of the road surface: when you drive on a damaged or poorly maintained road surface, with potholes full of water which hide their depth, your tyres incur numerous impacts which can tear off microparticles of rubber and result in more rapid wear to the lugs and lateral wear to the sidewalls which are less resistant. In certain extreme cases, this can lead to a frontal impact and generate an internal break in certain components of the casing, or a break in the tread. If you can change route to take a road that is less damaged even if it is longer, this would be a better, more economic choice because replacing a set of tyres is much more costly than an extra tank of petrol.
This is also one of the frequent causes of wear to your agricultural tyres. Agricultural tyres are effectively not designed to withstand difficult working conditions in the forest.
Wear linked to hard surface forest clearing operations
If you need to collect wood or carry out forest clearing operations, you should use forestry tyres that are suitable for this purpose and which were designed to withstand sharp stones, pointed branches and tree stumps, etc.
When you work in the farm courtyard
Try to avoid excessive on-the-spot manoeuvres, because this will rapidly damage the rubber of your tyres.
Repeated turning circles on concrete with a front loader to load the trailers or store fodder could lead to breaks at the lug base, making the tyre rapidly unfit for use.
Certain tyre models are designed for this type of work and will be more suitable if this is a daily activity.
To help you clearly define the causes of premature wear on your current tyres, we have developed a complete guide for you to download free of charge "How to detect abnormal wear in my tractor tyres"
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This information is intended only to make you aware of the technical and functional aspects of agricultural tires and their use. It does not allow you to make a judgment or a definitive conclusion on a given problem. Only your agricultural tire expert is able to make a technical assessment and take a final decision, case by case.