Tyre markings on a tractor

Tyre markings on a tractor

How to read the markings on a tyre?

The sidewall of a tyre shows its size, but not only that. There are also additional tyre markings in the form of acronyms and numbers that correspond to specific information. How do you decipher them? Our experts explain it all in detail in this article.


Tractor tyre size explained in less than 5 minutes

To get straight to the point, here's a video giving you the main points about tyre markings. We'll go into more detail in the rest of the article.

A concrete example of tractor tyre size

What do the markings on my agricultural tyres mean?

Let's take a concrete example with a MICHELIN Xeobib tyre and look closely at what the tyre markings on the sidewall mean:

MICHELIN: The manufacturer's brand always appears on the sidewall of the tyre.

XeoBib: The name of the range (here "Xeobib") is indicated near the brand. A range is designed to suit a particular type of vehicle and to meet a specific need.

VF = stands for "Very High Flexion": This prefix designates a standardised category of tyres - Tyres designed to bear 40% more load at the same pressure(2). At Michelin, the VF or IF standard corresponds to our UltraFlex Technology tyres | MICHELIN UK , which allows longer footprints to limit soil compaction and rutting. 

The tyre size is part of the tractor s tyre markings

the tyre size is part of the tractor s tyre markings

Then we find the tyre markings that corresponds to the size:

650: Nominal section width in mm. This tyre marking corresponds to the distance between the left and right sidewalls of the tyre.

60: Aspect ratio in % (sidewall height/nominal section width). In this example the height of the sidewall is 60% of the nominal section width of 650mm.

R: Defines the structure: “R” is for radial. If it wasn't a radial tyre, a simple dash "-" would designate it as a cross-ply tyre.

38: Nominal diameter of the rim in inches.

155: Standardised load index. This is an index corresponding to the nominal load the tyre can support. You can consult our load index chart to find out the maximum load in kilos corresponding to your load index.

D: Standardised speed index. This is an index corresponding to the maximum speed This is an index corresponding to a maximum speed at which the tyre can be driven. See our speed index chart.

Radial: Construction type.

RC = "Rolling circumference" in mm

E = Tyre section width in mm.

Tubeless: Tyre without an inner tube

Michelin® X®: Trademark

Other tyre markings that may appear on the sidewall

Let's go through the list of tyre markings that may be found on the sidewall of a tyre and their corresponding information.

IF = "Improved Flexion": This prefix designates a standardised category of tyres designed to bear 20% more load at the same pressure.(1)

VF = "Very High Flexion": As seen in our example above, this prefix designates a standardised category of tyres designed to bear 40% more load at the same pressure(2).

PFO = "Pressure Field Operation": This tyre marking is an ETRTO* standard that enables tractor IF/VF tyres to bear a higher load at a lower speed (1)(2). *ETRTO = European Tyre and Rim Technical Organisation

Other AG tyre markings

Other AG tyre markings


CFO = "Cyclic Field Operation": implies an improved cyclic field operation. CFO indicates that tyres are designed to provide additional load capacity in the field over 1.5 km maximum.(3)

TL = "Tubeless": which means that the tyre has no inner tube. At Michelin, we only manufacture tubeless tyres for agricultural machinery.

IMP = "Implement": This tyre marking means that the tyre is mainly designed for implements or trailers. It can also equip the front steering wheels and drive wheels of farming tractors and forestry tractors but is not suited for sustained work at high torque.

IND = "Industrial": Marking on tyres for construction applications with load and pressure capacities that are different from tyres with the same designation and the same size for agricultural applications.

NRO = "Narrow Rim Option": Experimental ETRTO standard that must be approved. It allows a much narrower rim to be used than the one normally authorised by ETRTO for IF and VF tyres.

CAI = "International article code": Identifies a product with a specific, unique 6-digit code

SRI = "Speed Radius Index": Parameter used to calculate the theoretical speed of vehicles during standardisation procedures in the European Union and for the interchangeability of different tyre sizes.


Pictograms are additional tyre markings that can be found on MICHELIN tyres. Here's what they mean.

MICHELIN Ultraflex Technology pictogram on AG tyre sidewall

MICHELIN Ultraflex technology pictogram

MICHELIN Ultraflex

MICHELIN Ultraflex Technology, invented by Michelin in 2004, is a game-changing innovation that enables agricultural vehicles to use much lower pressure and thus protect the soil, increasing crop yieldsThis symbol means that the tyre is equipped with this technology.

High traction pictogram

high traction pictogram

High Traction

This pictogram means that your tyre has been designed to provide high level of grip for a better traction in the field.

To find out more, read our article on "How to improve traction"

Air systems ready pictogram

air systems ready pictogram

Air system ready

If the tyre is "Air Systems Ready", it is compatible with the CTIS (Central Tyre Inflation System), which allows you to control tyre pressure from your cab.

Stubble shield pictogram

stubble shield pictogram

Stubble shield

This pictogram means that the tyre is designed with special protection against stubble damage.
See our article on tyre damage.

Maximum fitting pressure pictogram

Maximum fitting pressure pictogram

Maximum fitting pressure

This symbol does not indicate the maximum pressure for driving with the tyre, but the maximum pressure when fitting the tyre to the rim.
Don't forget to adjust to the correct pressure once the tyre is fitted.
To find out more, read our dedicated article.

Casing and rim dimensions

"It can also be useful to know what the dimension of the casing and the rim are. The diagram below offers an explanation:

Casing and rim dimensions

Casing and rim dimensions



S: Section width of the tyre
R': The Static Laden Radius in mm. 
R: Radius without load
D: External diameter, equal to 2 x R


Ø: Rim diameter in inches
F: Internal width
H: Section height

To know more about rims, discover our article on "Understanding Rims, Inner tubes and Valves".


(1) Compared to non IF (High Flexion) tyre
(2) Compared to non VF (Very High Flexion) tyre
(3) Compared to non CFO tyre

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