9 vital technical points in relation to agricultural tyres

While agricultural tyres may seem simple, their technicality and complexity go well beyond their physical appearance. They play an essential role in the performance of your tractor and can have a major impact in the event of problems. To ensure that you use your tyres efficiently, it is essential to manage the technical settings right, such as parallelism and lead. In addition, understanding the different technical points linked to agricultural tyres is vital if you wish to preserve your equipment, protect your soil and extend their lifespan. Whether it’s when choosing new tyres, mounting or demounting them, selecting rims or settings, many technical aspects must be properly understood to guarantee optimal working conditions.

In this article we look at the vital technical points to know to allow you to manage your agricultural tyres better:

1. Important technical points for mounting and demounting tyres

If you are involved in mounting and demounting your agricultural tyres, there are many factors to take into consideration, because a minor error could render your new tyres totally unfit for use, which would end up causing you a double economic sanction. Here are a few essential technical points to ensure that mounting and demounting operations will go ahead smoothly.

A few technical points to bear in mind:

• Suitable rims:
  When you replace your agricultural tyres, ensure that the rim corresponds to the characteristics of your new tyre to avoid any incident of rotation of the tyre on the rim and damage to the bead.
  

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• Compatible dimensions:
  Opt for a tyre size that corresponds to your tractor and its engine power to avoid damaging the transmission as a result of incorrect lead.
  

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• Do not neglect safety precautions:
  During mounting, create a secure work space around your tractor and avoid propping it up with a jack which could give way during the operation, using chocks and stands instead to be sure that your tractor is securely stabilised.
  

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• Clean the rim seats:
  Before mounting the tyre, clean the bead seats on the rims to eliminate excess rust or dirt and avoid premature wear.
  

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• Check the valve:
  Check that the valve is airtight and replace it systematically if you have any doubt, to make sure that you don’t end up with a flat tyre.
  

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• Adequate lubrication:
  Use a suitable lubricant to position the tyres correctly and avoid rotation on the rim after mounting.
  

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• Check the beads:
  Ensure the beads are correctly positioned to avoid unwanted vibration.
  

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• Inflation pressure:
  Be careful during inflation not to go beyond the maximum recommended pressure to prevent any risk of explosion.
  

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2. Why are there different types of rim?

Perhaps your original rim does not let you make full use of your engine power, is not solid enough to carry a heavier load, or perhaps it is unsuitable for work with a high volume of air to protect your soil. There are different types of rim, which we present in detail below:

The rim is much more than a simple metal ring,  because it bears the weight of the tractor and transmits engine torque to the tyre then to the ground, which makes its resistance capacity essential.

There are three principal types of rim: W, DW and TW, each with specific advantages.

• The W rim is the oldest model, which is suitable for small tyres.
• The DW rim is used for its good rigidity and ease of mounting.
• The TW rim is extra resistant and even easier to mount.

3. Do you need to check parallelism often?

Ideally, tyres must be parallel to the tractor to ensure the correct use of your machine. However, toe-out of around 1.5 in the front wheels is recommended. This makes it possible to offset the strain on the front axle, when the tractor is working in four-wheel drive.

Unfortunately, when working on rugged terrain, vibrations and ruts cause a progressive misalignment of the wheels. Very regular inspection of your tractor tyre alignment makes it possible to avoid premature wear to your tyres.

Lack of parallelism

This takes two forms, either toe-in (the wheels point inwards towards each other) which causes wear to the outer side of the tyres, or toe-out (the wheels point outwards away from each other) which causes wear to the inner side of the tyres. In general, problems with the front axle tend to lead to toe-in, due to mechanical strain, when working in four-wheel drive. In both cases, the lifespan of the tyres is reduced.

It is important to check regularly because a few millimetres are enough to accelerate wear:

• For a setting error of 5mm, your tyres’ lifespan will be reduced by around 12%
• If the error reaches 15mm of toe-in or toe-out, this reduction in lifespan may reach up to 36%.

Adjusting parallelism

When you notice an irregularity with steering, vibrations or visible wear to one side of the tyres, this is likely to come from a lack of parallelism, which should be corrected rapidly.

4. Why is it useful to change the size of your tractor tyres?

Changing the size of your tractor tyres can bring some significant advantages to improve the efficiency of your tractor.

• Extra load:
  By opting for wider tyres, you increase the volume of air, and therefore your load capacity, without having to increase inflation pressure.
  

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• Soil preservation:
  Wider tyres have a larger contact patch with the ground, which reduces soil compaction.
  

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• Optimisation of traction power:
  Large tyres grip the ground better. They improve traction, allowing you to work more rapidly and save on fuel.
  

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Changing the size of your tractor tyres can significantly improve the efficiency of your agricultural machine and preserve the quality of your soil while improving your productivity.

5. What is the impact of lead?

Adopting the right lead settings when you change your tyres is crucial if you want to work more efficiently. This corresponds to the correct synchronisation of front and rear axles on four-wheel drive tractors with front and rear tyres that are not the same size. A correct lead ratio allows the front axle of the tractor to pull slightly more than the rear axle. This guarantees perfect drive axis synchronisation, improving the machine’s overall traction.

Incorrect lead can have negative consequences on the handling and the stability of your tractor, as well as on tyre wear and your fuel consumption:

• If the lead ratio is too high (above 5%), the front axle turns too fast and pulls the rear axle. This leads to premature wear to the front tyres as well as excess fuel consumption.
  

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• If the lead ratio is too low (lag/below 0%), the rear axle pushes the front axle, or the front axle slows down the rear axle, which has the same effect.
  

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• In both cases, mechanical damages may ensue (overheating of the hub reducer, abnormal wear to the transmission pinion).
  

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• Excess slip: with incorrect lead, slip occurs, the wheels cannot maintain optimal adherence to the ground. This reduces the traction capacity and may render the tractor less efficient, especially in wet conditions.

6. How to increase load while avoiding overloading your tyres?

Increasing your load may seem to be a great way of boosting your productivity by using wider, thus heavier implements. However, you must bear in mind your tyres’ load capacity to avoid the risk of overloading them, which could harm the overall efficiency of your tractor.

Here is how to optimise the load while avoiding problems linked to overloading:

• Check the load regularly in order to compensate with pressure: each tyre model has a specific load index (marked on the sidewall) which you must not go beyond if you wish to avoid premature wear. It is essential to adjust pressure based on load to preserve your tyres. Suitable inflation pressure reduces the risks of wear and excessive deformation of the sidewalls.
  

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• Spread the load correctly between the front and rear axle: for a four-wheel drive tractor, it is recommended to place 35 to 40% of the load on the front axle and 60 to 65% on the rear axle. Ballasting by adding additional weight to the front lifting system makes it possible to balance out the vehicle weight and improve traction.
  

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• Use high-tech tyres such as IF or VF tyres which are designed to carry more weight than standard tyres. The flexion capacity in their sidewalls allows them to adapt better to variations in load.
  

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7. What do you gain by storing agricultural tyres correctly

Storing your agricultural tyres properly will extend their lifespan, giving you the possibility of saving money in the long run.

Here is some advice on the best storage conditions for your tyres:

• Once the tyres have been demounted, store them inside in a dry place at a moderate temperature and away from sources of light.
• Keep sources of ozone and chemical substances at a distance.
• Avoid hanging them up, transporting them with chains or lifting them with a forklift at the level of the bead.
• Rotate the tyres a quarter of a turn regularly to avoid damage to the part in contact with the ground.

8. What do you need to know about breakdowns?

To avoid emergency breakdowns which may be costly and time consuming, bear in mind that a large number of these incidents can be avoided. A regular inspection of your tyres allows you to detect any sign of excessive wear or irregularities such as deep cuts or small hernias. Repairs are always simpler and cheaper to carry out in your barn than in the middle of the fields.

How long does it take breakdown services to come out?

The breakdown response time for a tyre technician can vary depending on the distance to cover. A competent professional can deal with a puncture in under four hours if the breakdown occurs not too far from his garage.

In the event of a problem, contact your agricultural tyre dealer or technician rapidly. Give very precise details about the problem (tyre size, accessibility of the machine…) so that they can prepare their intervention. If they don’t have your tyre model in stock, they can offer you a spare tyre in the same size while you wait for your new tyre to be delivered.

9. In what case should you call in a tyre expert?

Calling in a tyre expert is essential if you are looking to improve your productivity. If you swap a standard tyre for a tyre that is optimally suited to your farm, you will improve efficiency and your work rate.

A tyre expert can help you:

• Carry out a tyre audit on your machine fleet to optimise the use of the tyres and machines based on the implements used and the work to be done.
  

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• Choose the most suitable tyre model for your activity, to improve your productivity, reduce the frequency at which you have to replace your tyres and reduce your fuel consumption.
  

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Turning to an agricultural tyre expert can improve the profitability of your farm while ensuring that your equipment lasts over time.

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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