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Narrow tyres to circulate easily between rows

Narrow versus standard tractor tyres for spraying

Authored by: Tractor tyre expert | 22 May 2023

What is the best choice of tyre for your tractor if you work with a sprayer in tow? Should you keep your usual wide tyre because it’s easier and quicker not to change tyres? Or must you absolutely change to narrow tyres to avoid squashing the crops? You might think that there is only a slight difference: it’s just a question of tyre width. But depending on the size of your farm, the difference in terms of yield will be significant. Given that spraying requires the most trips back and forth across your fields behind the tractor, it’s clear that the impact is not going to be neutral.

In this article we will look at the cases in which you can keep your original tyre and the instances when it would be better to swap them for narrow tyres:

1. Wide tyres are best in certain conditions only

Everything is relative, and when we talk about wide wheels, the result will depend essentially on the tyre technology used.

Wide tyres, if you have low-pressure VF tyres which work regularly at a pressure of 0.8 bar when loaded, can be used during the first spraying operations at the end of the winter season, for the first liquid fertiliser inputs.

In this case, narrow tyres which require a higher inflation pressure and don’t have a large contact area with the ground will be less suitable.

A wide VF tyre effectively spreads the weight to the ground better and avoids soil compaction in wet conditions.

For all fertilizer operations carried out before sowing, the use of a wide wheel equipped with a low-pressure tyre has numerous advantages:

  • A high load capacity: low-pressure tyres have a supple yet robust casing, capable of bearing heavy loads (longer booms, bigger sprayer tanks…).
  • Working at a pressure of 0.8 bar avoids soil compaction and the formation of ruts during soil preparation or fertilizer operations prior to sowing.
  • VF tyres do not require pressure adjustments during cyclic operations and can work at the same inflation pressure with a full or empty sprayer tank.

Using standard tyres on wide wheels is not advisable

The impact of a very low-pressure tyre which can work at 0.8 bar will be very different from that of a standard technology tyre which requires an inflation pressure of at least 1.6 bar to compensate for the thousands of litres transported in the sprayer tank, or more if you are equipped with long boom arms which will cause a significant load transfer to the rear axle.

With a standard tyre you will have to adapt pressure based on load, which is not easy with the variable load caused by the tank being regularly emptied, which makes the weight on your tyres vary by several thousand kilos.

Standard tyres with a high inflation pressure are incompatible with wet soil
Standard tyres with a high inflation pressure
are incompatible with wet soil

 

Wide standard technology tyres will effectively have to work at a high inflation pressure to compensate for the weight of the full tank at the start of operations, then bear the load transfer when the boom arms are deployed.

The damage to the soil and to seedlings will be considerable, with a loss of yield linked to the areas impacted by the tyres.

Ruts linked to the passage of heavy spraying equipment, with standard highly inflated tyres
Ruts linked to the passage of heavy spraying equipment,
with standard highly inflated tyres

 

Standard tyres are not suitable for spraying during the wet season, as damage to the ground will be significant in terms of compaction of the lower layers of soil.

You will then have to use a subsoiler to restore the land at the end of the season, if you wish to avoid non-productive ruts in the middle of your fields. This leads to additional fuel costs and a loss of time which could have been avoided with tyres that are adapted to the work to be carried out.

 

2. Narrow tyres have less impact on the soil surface during spraying

During the spring if it is not too wet or in the summer, narrow tyres will be more suitable, because they preserve the young seedlings.

Unlike wide tyres which crush the crops, narrow tyres have less impact on the soil surface and allow young seedlings to develop correctly throughout the field.

Low impact of Performer 95 tyres on crops despite the inflation pressure
Low impact of Performer 95 tyres on crops despite the inflation pressure

 

There is less impact on the crop root system with narrow tyres

Beyond it being easier to pass between the rows with narrow tyres compared to wide tyres, the impact on soil compaction cannot be seen directly.

However, for both types of tyre the inflation pressure will be high to bear the weight of the boom arms when deployed and the full sprayer tank, so in both cases there will be compaction.

The limited width of the soil footprint with narrow tyres limits the number of plants damaged as well as the in-depth impact on your crop roots.

Reduction of the compaction zone with a narrow tyre
Reduction of the compaction zone with a narrow tyre

 

If you use a tractor-drawn sprayer you will have to fit the combination vehicle with narrow tyres so that the wheels can follow in the same tracks between the rows and have less impact on the soil surface.

To reduce the impact on the soil even further when using a towed sprayer, you should make the tractor as light as possible by removing any weights or ballast because it’s not tractive force that is needed but speed of travel to complete the spraying operation correctly.

By making the tractor lighter, you reduce rolling resistance and therefore the impact on the ground.

 

3. The size of the spray width is decisive for soil preservation

The larger the spray width, the less trips the tractor has to make, so the less the soil will be compacted. When opting for a tractor drawn sprayer, you can choose to work with a sprayer tank with a bigger volume which can contain up to 8,000 litres and with longer aluminium boom arms that can reach a spray width of 50 meters.

This large spray width allows you to save time in covering the entire area to be treated while reducing the number of passages across the field.

The spray width is crucial
The spray width is crucial

 

4. Which narrow tyre can resist load to work with a large spray width?

A narrow tyre requires a sophisticated technical design because it has to cope with many different types of strain, and opposing forces, in order to carry a heavy load with a small contact patch with the ground, but while maintaining a high level of sturdiness and stability.

Firestone’s Performer 95 has been designed for cyclic loads with sprayers, and contains steel chords between the casing plies and the tread which allow it to carry heavier loads.

There are many advantages to be gained by opting for this type of premium tyre:

A higher load capacity

  • A resistant, robust casing which includes two steel belts positioned in a criss-cross patten to resist load, even at high speed. It can reach a maximum load with a drawn implement of more than 5,800 kg per tyre for the biggest tyre sizes:
    • 340/85 R48 = 5,865 kg at 4.5 bar at 10 km/h in cyclic operations or 3,625 kg at 3.6 bar at 50 km/h on the road
    • 300/95 R52 = 5,865 kg at 5 bar at 10 km/h in cyclic operations or 3,625 kg at 4 bar at 50 km/h on the road
Rogator Challenger self-propelled sprayer (4,800 litre tank, 30 metre boom width) equipped with Performer 95 –380/105R50 tyres
Rogator Challenger self-propelled sprayer (4,800 litre tank, 30 metre boom width)
equipped with Performer 95 –380/105 R50 tyres

 

  • Being able to carry more load for spraying operations means that you can increase the size of the tank, thus reducing the number of trips back and forth to fill it up which is costly in fuel and in time spent.
  • Its more resistant tread allows the Performer 95 to work with a greater range of pressure settings which vary from 0.8 bar to 5 bar with cyclic loads.

Very good traction capacity

As the contact patch with the ground is reduced, the narrow tyre needs very specific lugs to ensure a good grip on the earth while avoiding slip.

  • The Performer 95’s Dual Angle lug has a unique design, offering a bigger contact patch with the ground than a standard lug as well as excellent self-cleaning capacities.

 

Firestone Performer 95 tyres
Firestone Performer 95 tyres

Better driving comfort and safety

The Performer 95 tyre offers excellent road handling capacities and driving comfort:

  • Excellent stability: Its steel belt acts as a shock absorber to provide better stability. It optimises the stability of the boom and thus precision in applying the phytosanitary products. If the tyres don’t absorb the imperfections in the ground sufficiently, the movement of liquid contained in the tank is transferred to the booms, especially if you work with long boom arms.
  • The Performer 95 tyre allows you to carry more load at high speeds (speed index D / 65 km/h). Even at these high speeds, it continues to offer very good road handling capacities, excellent steering precision and a much better driving comfort with less vibrations and noise.

 

CONCLUSION

The narrow tyre is clearly the best solution for spraying simply to be able to pass between the rows without damaging the plants. The impacted surface area in your field will be smaller and there will be almost no negative effect on your productivity.

The investment will be largely profitable compared to the work that a standard tyre can do. If you take it one step further and choose a high-tech narrow tyre which allows you to work with cyclic loads, with a very high inflation pressure, to use a high capacity tank and long boom arms, you will see a significant improvement in productivity.

 


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Topic: Soil compaction

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