IF and VF tyres – more load or lower pressure

More and more tractor tyres carry IF or VF before the size, for example VF 710/70R42. These tyres are built to work with more deflection than ordinary radials. In practice they carry more load at the same pressure, or the same load at lower pressure. This guide explains the difference and uses the manufacturers' own tables to show how big the benefit really is.

What do IF and VF mean?

• IF – Improved Flexion: under the industry standard, up to about 20 % more load than a standard tyre of the same size at the same pressure.
• VF – Very High Flexion: up to about 40 % more load at the same pressure.

These are upper limits. What a particular tyre carries depends on speed, pressure and construction, so the table for that tyre always applies.

Comparison with real data

Load per tyre in kg at 40 km/h from each manufacturer's databook:

In these examples at 40 km/h the VF tyres carried 26–35 % more and the IF tyre 9–10 % more. That is less than the standard's 40 and 20 % maximums, which is why you should use the table rather than a rule of thumb. See Trelleborg, Vredestein and Firestone.

Lower pressure for the same load

For many farmers the main benefit is running lower pressure. Example with 5,000 kg per tyre, Trelleborg 710/70R42:

The VF tyre carries the same load at 0.4 bar less in both cases. With the app's contact model (mean contact pressure ≈ 1.1 × inflation) that means clearly lower stress on the topsoil, see soil compaction and tyre pressure. Another example: Vredestein's VF 650/65R42 carries 4,500 kg at 1.0 bar at 40 km/h, where the standard tyre needs 1.6 bar.

When do IF/VF tyres pay off?

• With high loads, such as heavy implements, big trailers or a front loader, when you want to keep pressure down.
• With a lot of field work on vulnerable soil where you want less compaction.
• When you need more capacity without going up a size, for example because of clearance.
• When you can change pressure between field and road, so the field benefit is actually used.

If you keep running the same high pressure as before, you get no compaction benefit. Weigh the gain against the higher price, see tyre cost per hour.

Things to watch

• Lead: IF/VF tyres often have a slightly different rolling circumference than standard tyres of the same size. Trelleborg's two 710/70R42 above are both 6,190 mm, but Vredestein's VF 650/65R42 is 5,690 mm against 5,740 mm for the standard tyre. Calculate lead, see tractor lead.
• Rims: some IF/VF tyres require or recommend rims suited to low pressure and high torque. Check the manufacturer's requirements.
• Mixing: avoid mixing IF/VF and standard tyres on the same axle.
• Pressure checks: low pressures need an accurate gauge and regular checks.
• Special rows: some IF/VF tables have rows for cyclic loads (CFO/PFO) or front loaders, with their own footnote conditions.

Step by step: choosing pressure for an IF/VF tyre

1. Work out the load per tyre, see axle load and implements.
2. Open the tyre's own table in the app. Do not use the standard tyre's table.
3. Choose the row by speed, and the HT row for heavy draft if there is one.
4. Read off the lowest pressure that carries the load.
5. Repeat for road transport and note both pressures.

Common mistakes

• Buying VF tyres but keeping the old pressure.
• Assuming 20 or 40 % more capacity instead of reading the table.
• Assuming the IF/VF tyre has the same rolling circumference as the old tyre.

Related questions

Are VF tyres better than IF tyres?

VF tolerates more deflection and has more margin under the standard, but usually costs more. The right choice depends on load, use and price.

Can I run VF on the rear and standard tyres on the front?

It happens, but lead must be right and each tyre must use the pressure from its own table.

What does CFO mean on IF and VF tyres?

CFO (Cyclic Field Operation) means the tyre may carry extra load under cyclic loading, for example on combines, under the manufacturer's conditions.

More examples: 600/70R30 front tyres

600/70R30 front tyres are common on larger tractors. Lowest pressure for 3,500 kg per tyre at 40 km/h per each maker's table:

Values are the lowest pressure in each table that carries the load. Some tables start at a minimum pressure at 40 km/h, which also affects the result.

The VF tyres manage with 0.2–0.4 bar less than the standard tyres here, but the spread between standard tyres from different brands is also worth noting. Compare individual tyres, not just types.

Checklist before buying IF/VF tyres

• What loads do you run, and how much time is field versus road?
• Can you change pressure between field and road, by hand or with a central inflation system?
• Does the new tyre pair give acceptable lead?
• Are the rims approved by the tyre maker?
• What is the price difference per hour against a standard tyre?

IF and VF tyres in our catalogue

Of the 4,990 tyres shown in the catalogue, 632 are marked VF and 155 IF, from several makers including Michelin, Continental, BKT, Mitas and Nokian. Search the size in the Catalog with IF or VF to see them.

Central tyre inflation systems

Low field pressures pay off most if pressure can be raised again before road work. Some tractors have systems that change tyre pressure on the move, which makes it easier to always use the table pressure in both field and road. Without one, the same table applies; you just adjust by hand.

How to do it in the app

Search the size in the Catalog and compare IF/VF and standard tyres. The Pressure guide shows the table and the lowest pressure that carries your load, and Marktryck compares two pressures side by side.

Frequently asked questions

What does VF mean on tractor tyres?

Very High Flexion: the tyre tolerates more deflection and, under the standard, can carry up to about 40 % more load at the same pressure, or the same load at lower pressure.

What does IF mean on tractor tyres?

Improved Flexion: up to about 20 % more load at the same pressure under the standard.

How much lower pressure can I run with VF tyres?

It depends on the tyre. In Trelleborg's 710/70R42 table with 5,000 kg per tyre, the VF tyre needs 0.4 bar less than the standard tyre.

Do VF tyres always carry 40 % more?

No. 40 % is an upper limit. In our examples at 40 km/h VF tyres carried 26–35 % more.

Do IF/VF tyres have the same rolling circumference as standard tyres?

Not always. Check the rolling circumference and calculate lead before changing.

Last updated 2026-10-15. General information. See disclaimer.