What is the proper tire pressure for a tractor?

Most people only pay attention to their tractor’s tire pressure when the tire is visibly flat, low on air, or a problem arises. But tire pressure matters much more than that. Among other things, it affects the engine’s power transfer to the ground, wheel slip, and fuel consumption. What’s more, not every task requires the same tire pressure.

What tire pressure should we set?

With tractors, it’s not possible to say definitively whether 1 or 2 bar is ideal. The correct pressure must always be adjusted to the specific tire, load, speed, and task. It also makes a big difference whether the machine is being used in a field or towed. For example, if a loaded trailer is attached, the optimal pressure will also be different.

In general, however, it can be said that the optimal tire pressure for a tractor is determined by the tire size, the work area, the nature of the work, the traction force, the travel speed, and soil conditions. On public roads, speed and load are the decisive factors, while in the field, traction requirements are the determining factor.

What tire pressure is needed in a field?

Let’s take a look, one by one, at where and why it’s needed. In a field, the goal isn’t simply for the tractor to drive safely. It’s more important to work with as much engine power as possible and as small a tire footprint as possible. In this case, low tire pressure can offer many advantages. First, the tire spreads out more, as it comes into contact with the ground over a larger area, so the machine’s weight is distributed over a larger surface. In addition, traction can improve, wheel slip can be reduced, and the soil does not become as compacted. For today’s agricultural machinery, this value is generally around 0.6 bar.

What Can We Expect on Public Roads?

When a tractor is traveling on public roads rather than working in the fields, the conditions are different. Higher speeds, longer operating times, and the tractor’s greater weight all require higher tire pressure.

Why is this important? Because higher pressure can reduce rolling resistance, which can optimize fuel consumption when driving on concrete. It is therefore best to set the pressure between 1.6 and 2 bar, which allows us to drive safely on the roads.

The Role of Tire Pressure in Soil Compaction

However, tire pressure does not only affect the tractor. The values we use also matter for the topsoil. High pressure can result in a smaller contact patch, which can be detrimental in wet conditions. Reducing pressure has been shown to increase the tire’s contact patch. In practice, this means the soil becomes less compacted. If the machine compacts the soil excessively, that area will have poorer water retention and reduced aeration, which in turn will affect root development.

What happens if the pressure is too low?

It’s true that there are situations where low pressure is useful, but that doesn’t mean that the lower the pressure, the better. This is because the tire must be able to support the tractor’s weight as well as the load resulting from the specific task.

When we try to work with too low a tire pressure, not only will the tractor’s performance suffer, but the tires may also be damaged. For example, the risk of deformation may increase, and even the rims could be damaged. This is even more important on hilly and sloped terrain, where the tires are subjected to even greater mechanical stress.

Checking Tire Pressure

A tractor isn’t just a regular car, where we tend to check the tire pressure relatively infrequently. It’s best to measure them regularly—preferably when the tires are cold—and pay special attention to periods when the type of work changes. Different pressures are needed during planting season, for soil preparation, during harvest month, and, of course, for transport. In fact, changing machinery, variations in load weight, and road speed can all affect the recommended tire pressure.

It is therefore always best to adjust the pressure to the specific conditions, the type of work, and the terrain. Lower pressure may be ideal on farmland, while higher pressure is recommended on public roads.