Authored by: Tractor tyre expert | 18 July 2023
During the past 15 years, there has been a major evolution in the size of harvest tyres. While the 650mm tyre size was the norm in the years 2000 to 2010, there is now a much higher demand for the 900 tyre size which offers real advantages and reflects a change in mentality and the size of modern farms.
When a trend is so pronounced, this clearly shows what works best for most farms. In this article we look at the reasons for such a rapid evolution in the use of harvest tyres.
Over the last sixty years, the demand for grain products has continued to rise, leading to a transformation of many small family farms into agricultural enterprises with a concentration of field crops on the arable land available.
During the same period, productivity has shot up together with the size of the machinery used and more specifically the harvesting machines.
If you work on an average sized farm or if it is made up of lots of small fields with roads in between them, you will certainly have a compact harvester that is easy to handle.
In this case a 650mm tyre is right for your working environment and the weight of your machine.
This is why it was the standard tyre size for a long period of time.
If the soil conditions are not ideal on your farm, if the terrain is rugged or if you live in a wet region, 650mm tyres will soon reach their limits.
If your soil tends to be soft, it will be necessary to increase the size of the tyre footprint to obtain a larger contact patch with the ground in order to improve traction, which will not be the case with 650mm tyres.
With tyres that are undersized compared to the weight carried by your harvester, you will be obliged to increase inflation pressure in order to cope with this load.
Rolling resistance will increase.
Your tyres will have a tendency to sink into the ground causing more slip and greater soil compaction.
Depending on your tyre technology, it may not be possible to work at a low inflation pressure with major consequences on future productivity in your fields.
This will be even more prejudicial during autumn harvesting, such as sunflower or grain maize.
This is the most common tyre dimension today, because it offers a good compromise between the load capacity and soil preservation.
The harvester is a major investment on a farm or at the least it plays a crucial role even if you only rent it.
This is the heaviest agricultural machine that will work in your fields and it would be a shame to damage your soil because the harvester is not properly equipped with the right tyres.
There are many benefits to be gained from increasing tyre dimensions compared to the 650mm tyre:
On large farms spanning one hundred hectares or more, the harvesters are generally bigger in order to boost productivity.
You need to be able to make the most of every harvest day to generate a high productivity level.
High air volume tyres which have a greater load capacity than standard tyres with average dimensions will therefore be much more suitable.
High air volume tyres which have a greater load capacity than standard tyres with average dimensions will therefore be much more suitable.
For powerful machines with a higher harvest throughput, the hopper has a higher load capacity and the tyres must be able to cope with this rapidly increasing load.
The variable quantity of grain in the harvester’s hopper has a direct impact on the tyres whose inflation pressure is not modified between each loading and unloading cycle.
This trend towards very large dimensions and high air volume tyres is also linked to the desire to preserve the soil in our fields.
The machines are more powerful and as such they are also heavier, which has major repercussions on deep soil compaction.
To compensate for this evolution towards heavier machines, 900mm tyres allow you to spread the load over a larger contact patch with the ground.
This is a high capacity tyre designed specifically for cyclic operations such as harvesting.
Its construction around a very robust casing makes it more resistant than standard tyres.
As it is perfectly adapted to powerful harvesters, this 900mm tyre is designed to carry 70% more load during cyclic operations.
The structure of the Maxi Traction Harvest tyre is reinforced with extra layers of fabric and stabilising ply to obtain an extremely robust casing.
The sidewalls are reinforced, which allows an optimal variation in pressure between 0.8 and 3.2 bar with a cyclic load bonus which allows you to increase pressure to up to 4 bar at a reduced speed.
It is also highly efficient in managing load transfer difficulties when working on sloping land or steep inclines.
| Tyre dimensions | Load capacity at 40 km/h - max. 3.2 bar | Cyclic load capacity at 10 km/h - max. 4 bar |
LOAD BONUS |
|---|---|---|---|
| 650/75 R32 | 6,300 kg | 10,710 kg | +70% |
| 800/65 R32 | 7,500 kg | 12,750 kg | +70% |
| 900/60 R32 | 8,250 kg | 14,025 kg | +70% |
The table above highlights the huge difference in load capacity between the three tyre dimensions, with a 30% capacity gain between a size 650 and a size 900 tyre, for a pressure of 3.2 bar and a speed of 40 km/h.
The difference is even greater with cyclic loads and can reach 14,025 kg with a 900mm tyre, i.e. a possible load of 28,000 kg on the front axle of a harvester.
The Maxi Traction Harvest tread has a specific design with asymmetric Dual Angle lugs which increase the contact patch with the ground.
Each lug has a better grip on the ground which multiplies the machine’s traction capacity.
The pulling capacity is boosted further with 900mm tyres which have a bigger contact patch with the ground. On large farms, optimal traction leads to less fuel and considerable time saving.
The evolution towards 900mm tyres with a high volume of air has occurred naturally over the last 20 years because of the resulting improvement in your harvesters’ capacities.
You can obtain a significant reduction in operating costs thanks to the time saved as a result of improved traction, the cyclic load bonus (which avoids having to interrupt production) and a very solid casing that is designed to last.
With Firestone, you have the guarantee of tractor tyres that deliver a real advantage, and that in choosing our brand, you can work worry-free.
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