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Fertilization: should you use bias tires or radial tires?

The fertilization period can be very complicated because of the weather. It's often during wet conditions that you're having to treat or apply fertilizer, which can have a major impact on soil compaction. If the soil is wet, the tires of your machine will compact the soil by crushing the pores and eliminating all the air that's in the micro-porosities. This is where you risk doing the most damage.

The best way to limit this is to work at low tire pressure. In fact, it's recommended that you do this every time you work in the field, whether it’s wet or dry conditions and even outside the fertilization period. When harvesting, for example, the risk of compaction is also high because the machinery used is heavier and compacts the soil.

But it's when you're working in wet conditions that the risk of compaction is increased. Fortunately, the right choice of tire technology can reduce this phenomenon.

Michelin invented radial technology in 1946. Why was this a major innovation? Because the principle of the radial tire is that the sidewalls are separated from the crown. So, when you deflate a radial tire, the sidewalls flatten out. And because the center of the tire is separated from the sidewalls, the area of contact with the ground is extended, taking on a rectangular shape.

On a bias tire, the crown and sidewalls are linked, which creates a domed shape. When the tire is deflated, this impacts the tread as much as the sidewalls, which means that the shape of the contact patch with the ground is elliptical, making it smaller than on a radial tire.

The advantage of radial ag tires is that by lowering the pressure, the tire's footprint on the ground is longer, and as the load is spread over a larger surface area, it is less per square inch.

There are two aspects to tire life: impact resistance and endurance.

A bias tire is more resistant to impacts because it contains several carcasses. On the other hand, it heats up a lot when it is under heavy stress, particularly during the fertilization phase when the tanks are heavy and the tires narrow.

A radial farm tire, which has only one carcass, deforms less and dissipates more heat, which makes it better in terms of thermal resistance. They are designed to be more durable than bias tires, because they have a greater surface area in contact with the ground.

The radial’s larger footprint means that the load is distributed more evenly, and consequently, the wear is more uniform and results in longer tire life. A bias tire, which has an elliptical ground surface, is subject to local overpressure, which tends to make it wear more quickly.

The three ranges of Michelin UltraFlex radial tires mentioned above are also compatible with the CTIS (Central Tire Inflation System)(**). With CTIS equipped, you can use this system to adjust tire pressure without leaving the cab of your vehicle, so that it's always at the optimum level no matter the terrain or your use.

Optimized tire pressure means you get all the benefits your tires can deliver (very low pressure with Michelin UltraFlex technology, less soil compaction, better traction) and avoid unnecessary fuel costs.