How can I find the correct tyre size that fits my tractor / agricultural vehicle?

Finding out which tyre sizes fits your tractor can be a difficult task. On this page we will explain where you can find the tyre size on you tyre and how you can understand this number.

Where do I find the tyre size on my  tractor?

The tyre size of a tractor or agricultural vehicle is printed on the side of the tyre. This is better known as the sidewall of the tyre. The image on the left shows an example of a letter/number combination that can be find on a tractor.

The number IF710/70R38 is shown on the image. We will use this number to elaborate the system on how to interpretend the tyre codes for tractors.

Large tractor tyre with the code IF710/70R38Large tractor tyre with the code IF710/70R38

How to read a tractor tyre?

A tractor tyre consists of different aspects. We will use tyre code IF710/70R38 to explain on how the tyre works.

Tyre technology (IF or VF)

The first to 2 letters in this example IF shows that this is a tractor tyre with special tyre technology. If a tyre has the identification VF or IF at the beginning of the sidewall, this indicates that the tyre is equiped with soil protection or soil friendly tyres.

These 2 types of tyres can be driving with 20% lower tyre pressure but also cary more than 20% extra load. If tyres are deinflated with 20% the tyres have more contact area than standard tyres. With more contact area, the load will be better spread and this will avoid excessive stress on the soil.

If a tyre is not equipped with this type of technology the first 3 digits will show the tyre width of the tyre

How to read tyre height of a tractor?

Tyre height is indicated after the slash ( / ) in the tyre size. The height of the tyre is given in percent, a height of 70 means that the tyre is 70% of the width of the tyre.
In this case the height is 70 % of 710 mm.

Radial tyres

The letter R indicates that this is a radial tyre.

How to read rim size of a tractor?

After the letter R (that indicates radial tyre) there is a number. In this instance it is number 38. This number indicates the size of the rim in inches

How to read load index of a tractor?

After the rim size there is a number and one letter left. The last number indicates the Load index of a tyre. The load index indicates on how much you load you can carry. This is very important with tractor tyres.

The common load index numbers of work van tyres have been collected in one overview. You can find this overview a couple of paragraphs down

How to read speed index?

After the load index number, there is still one letter left. This letter shows the speed index of the tractor tyre.

The common speed index numbers of work van tyres have been collected in one overview. You can find this overview a couple of paragraphs down

A tractor tyre with soil protecting technology (IF or VF)A tractor tyre with soil protecting technology (IF or VF)

Load speed index overview

Work vans and light commercial vehicles have specific load capacity rules. It is therefore very important to choose the right tyre that corresponds to the load capacity indicated by the manufacturer of the truck or trailer.

Periodic inspections check whether the tyres correspond to the load capacity specified by the manufacturer. If this number is not correct, the entire truck or trailer will be rejected.

Load index Weight (kg) Load index Weight (kg) Load index Weight (kg)
228 31.500 242 47.500 256 71.000
229 32.500 243 48.750 257 73.000
230 33.500 244 50.000 258 75.000
231 34.500 245 51.500 259 77.500
232 35.500 246 53.000 260 80.000
233 36.500 247 54.500 261 82.500
 234 37.500 248 56.000 262 85.000
235 38.750 249 58.000 263 87.500
236 40.000 250 60.000 264 90.000
237 41.250 251 61.500 265 92.500
238 42.500 252 63.000 266 95.000
239 43.750 253 65.000 267 97.500
240 45.000 254 67.000 268 100.000
241 46.250 255 69.000 269 103.000

Speed index overview

In the overview on the right you can see the speed rating that can be found on the side of the tyre with the corrosponding maximum speed rating.

Speed rating tyre Maximum speed Speed rating Maximum speed
A1 5 km/h B 50 km/h
A2 10 km/h C 60 km/h
A3 15 km/h D 65 km/h
A4 20 km/h E 70 km/h
A5 25 km/h F 80 km/h
A6 30 km/h G 90 km/h
A7 35 km/h J 100 km/h
A8 40 km/h    
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