Increase the volume of your tyres to boost your tractor

When the time comes to replace your tyres, it is often simpler to choose exactly the same tyre as for the tractor’s original mount; same brand, same model and same dimensions.
This may seem logical and more economical to you, yet this is probably not the wisest choice…. You can improve your tractor’s capacities considerably simply by changing the tyres for a model that is perfectly suited to your actual use of the tractor. There is an opportunity here to increase your tractor’s load capacity, for better soil preservation, to improve traction, to optimise your harvests and to save on fuel.

You must be aware that your tractor’s original mount is perhaps not the best suit to your actual tractor use or that more tyre options in dimension & technologies became available since your tractor purchase.

Increasing your tyre size offers you a major advantage

The more you increase the volume of air in your tyre, the more you will be able to increase the load and therefore use heavier and bigger tooling to improve your productivity and cultivate a wider area in the same time, while preserving your soil even better.

OPTION 1: pressure

You can, of course, increase pressure while keeping your current tyre size. However, there is major disadvantage to this: the pressure within the tyre is related to the pressure exerted on the ground, so with this option, you will cause excessive compaction of the deep soil layers and a major loss of productivity after a few seasons of operating in these conditions. This option must therefore be ruled out.

OPTION 2 : volume

When replacing your tyres, the possibility of opting for a larger series will allow you to have a greater volume of air without increasing pressure and to carry more load, and as such bigger and more efficient tooling, without causing additional soil compaction. You will still be within the recommended lead ratio defined by the tractor manufacturer.

Can you mount bigger tyres without changing the rim?

The tyre to be replaced has precise dimensions indicated on the sidewall.
To optimise your budget and improve your profitability, it is wiser to increase your investment slightly in tyres that are perfectly adapted to your use in order to better utilise your tractor capacities without spending more time.

What you need to know is that each rim model can accommodate slightly larger tyres. The lateral marking on the sidewall will give you all the indications. If the tyre marking is according to ETRTO standards, there are three parts:

EXAMPLE: 380/85 R28

380 represents the width of the tyre in mm

85 represents the height of the tyre’s sidewall (as a percentage of the width)
in this case: 380 x 85% = 320 mm

28 represents the rim diameter in inches, i.e.
in this case: 28 x 25.4 = 710 mm (1 inch = 25.4 mm)

You can mount on the same rim (in this case a 28-inch W13 rim) a slightly bigger tyre series, i.e. series 75 or 70.
This means that the volume of air will increase as well as the width of the tread, making it possible to have considerably more air to bear a greater load and obtain better traction because the contact patch is larger.

So to replace a tyre size: 380/85 R28

You can use a slightly bigger tyres from the ranges above:

420/75 R28 i.e. a tyre width of 420 mm with the same 28-inch W13 rim

420/70 R28 i.e. a tyre width of 420 mm with the same 28-inch W13 rim

However, by keeping exactly the same rim, the benefit will be limited, in the range of 4 to 5% overall improvement, which remains very difficult to measure if you take into account all other parameters.

Is there a better option, to really improve your tractor’s capacities?

Without changing the rim, you will gain a few centimetres in width, which means that you will cause a little less soil compaction with the same load.
However, for you to see and feel the difference by your own eyes and in your purse at the end of every coming year, don’t hesitate to use all the power of your tractor by widening your rims or replacing them to allow for a much bigger tyre:

Let’s go back to the example of changing a 380/85 R28 dimension tyre. By opting for wider W16L rims, you can move to:

VF 480/65 R28

Which is a tyre width of 480 mm with a 28-inch W16L rim. You will be able to work:

• at 0.8 bar carrying 2060 kg par pneu
• at 1.0 bar carrying 2360 kg par pneu
• at 1.2 bar carrying 2640 kg par pneu

ANOTHER EXAMPLE:

Here are the tyre upgrade possibilities for a 165 hp or 190 hp tractor taking into account the front and rear dimensions with a change or rims.

FRONT TYRES: possible changes in tyre size

420/85 R28 139D

Which is a tyre width of 420 mm with a 28-inch W15 rim.
You will be able to work at a speed of 30 km/h:

• at 0.8 bar carrying 1760 kg per tyre
• at 1.0 bar carrying 2015 kg per tyre
• at 1.2 bar carrying 2290 kg per tyre

480/70 R28 140D

Which is a tyre width of 480 mm with a 28-inch W15 rim.
You will be able to work at a speed of 30 km/h:

• at 0.8 bar carrying 1810 kg per tyre
• at 1.0 bar carrying 2040 kg per tyre
• at 1.2 bar carrying 2350 kg per tyre

VF 540/65 R28 145D

Which is a tyre width of 540 mm with a 28-inch W18L rim.
You will be able to work at a speed of 50 km/h:

• at 0.8 bar carrying 2450 kg per tyre
• at 1.0 bar carrying 2800 kg per tyre
• at 1.2 bar carrying 3135 kg per tyre

VF 600/60 R28 146D

Which is a tyre width of 600 mm with a 28-inch DW20B rim.
You will be able to work at a speed of 50 km/h:

• at 0.8 bar carrying 2650 kg per tyre
• at 1.0 bar carrying 3000 kg per tyre
• at 1.2 bar carrying 3120 kg per tyre

REAR TYRES: possible changes in tyre size

520/85 R38 155D

Which is a tyre width of 520 mm with a 38-inch W18L rim.
You will be able to work at a speed of 30 km/h:

• at 0.8 bar carrying 2805 kg per tyre
• at 1.0 bar carrying 3210 kg per tyre
• at 1.2 bar carrying 3645 kg per tyre

580/70 R38 155D

Which is a tyre width of 580 mm with a 38-inch W18L rim.
You will be able to work at a speed of 30 km/h:

• at 0.8 bar carrying 2805 kg per tyre
• at 1.0 bar carrying 3210 kg per tyre
• at 1.2 bar carrying 3645 kg per tyre

710/75 R34 178 A8

Which is a tyre width of 710 mm with a 34-inch DW23B rim.
You will be able to work at a speed of 30 km/h:

• at 0.8 bar carrying 3855 kg per tyre
• at 1.0 bar carrying 4360 kg per tyre
• at 1.2 bar carrying 4820 kg per tyre

VF 650/65 R38 169D

Which is a tyre width of 650 mm with a 38-inch DW23B rim.
You will be able to work at a speed of 50 km/h:

• at 0.8 bar carrying 3750 kg per tyre
• at 1.0 bar carrying 4250 kg per tyre
• at 1.2 bar carrying 4795 kg per tyre

VF 620/70 R42 172D

Which is a tyre width of 620 mm with a 42-inch DW23B rim.
You will be able to work at a speed of 50 km/h:

• at 0.8 bar carrying 4080 kg per tyre
• at 1.0 bar carrying 4625 kg per tyre
• at 1.0 bar carrying 5180 kg per tyre

VF 710/70 R38 178D

Which is a tyre width of 710 mm with a 38-inch DW25B rim.
You will be able to work at a speed of 50 km/h:

• at 0.8 bar carrying 4815 kg per tyre
• at 1.0 bar carrying 5450 kg per tyre
• at 1.2 bar carrying 6165 kg per tyre

VF 900/50 R42 180D

Which is a tyre width of 900 mm with a 42-inch DW30B rim.
You will be able to work at a maximum speed of 50 km/h:

• at 0.8 bar carrying 5140 kg per tyre
• at 1.0 bar carrying 5795 kg per tyre
• at 1.2 bar carrying 6565 kg per tyre

ATTENTION ith 4-wheel drive tractors, the change in size or tyre series for the front or rear tyres requires systematic verification of all the dimensions to respect the lead ratio specified by the manufacturer. The tyre mounting must be homogeneous on the tractor so that the front axle leads the rear axle by a small percentage.

You can carry 40% more load just by changing the type of tyre

Your current tractor was equipped with standard radial tyres. When it is time to replace your current tyres, you have the opportunity to opt for a VF technology wide rim.

Example for harvesting machines: combine harvester, forager, beet/chicory harvester, etc.

With its more innovative design and sturdy materials, the VF tyre has an built-in massive flexion capacity, its sidewalls are less rigid and more resistant at the same time. Its reinforced casing structure easily bears 40% more load than a normal tyre construction.

Substantial advantage, no more problems linked to unsuitable tyre pressure: it is no longer necessary to adjust the tyre pressure when going from one field to the other or doing other farming activities.
This VF technology offers real time saving and comfort for farmers who are always in a hurry, and who are not always aware what pressure to adopt on the road or for their field operations.
You must be careful nonetheless to adjust pressure on the basis of the weight of the tractor + tooling before starting the activities.

More load while preserving your soil better by increasing the contact patch

More load means more soil compaction and a progressive deterioration, passage after passage, of the plants’ root system. However, the technology developed for VF tyres means that pressure is reduced thus protecting the soil better than with standard agricultural tyres.
According to manufacturer tests, with an equivalent load, a low pressure VF tyre makes it possible to decrease pressure by 30 to 40% at 50 km/h and by 40% at 30 km/h.

VF technology makes it possible to reduce pressure sufficiently to increase the contact area on the ground. Inflation pressure may be lower than 0.8 bar whereas a standard agricultural tyre cannot go below 1.2 bar. This larger contact patch allows you to make use of the entire width of the tyre while reducing the depth of the tyre footprint. The contact patch on the ground is therefore larger and the load better distributed.

Much-improved tractive force

Your tractor tyre is your only contact with the ground; if you slide a little or slip too heavily, you will increase your fuel consumption, slow down your work rate and you may easily lose 30 minutes to an hour every day.

With a VF technology agricultural tyre, you will be able to increase the contact patch between the ground and the tyre, the entire length and depth of the lugs will grip the ground evenly, thus spreading the tractive effort over a larger area of the ground.
The slipratio will be reduced considerably and the transmission of the tractive effort will be more evenly transmitted to the ground, making it possible to reduce your fuel consumption or increase your speed and save more than an hour per day or cover a larger surface area in the same time.

The Bridgestone-agriculture.eu blog is written and administered by tractor tyre experts who are available to provide you with the advice you need on the subject of your agricultural tyres. They allow you to maximise your productivity with information on all subjects linked to tyres: Cheap tractor tyres — Technical data for agricultural tyres — Air pressure advice — Solutions to avoid soil compaction — Sprayer tyre pressure — Why and how to ballast your tractor tyres — When to use dual wheels — The mechanical causes of abnormal wear — Cheap agricultural tyres – etc…

To learn more and boost your farm's profits, Bridgestone-Agriculture is offering you a free, detailed white paper that explains the essential role your agricultural tyres play in your productivity.

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