What to check when buying tractor tyres

Tractor tyres are expensive and the wrong choice costs money and strains the tractor. Knowing the points below before visiting the dealer makes the right choice easier.

1. Know the factory size

Find the size the tractor left the factory with: read the current sidewall or look your model up on Tractor-Size. A previous owner may have fitted a different size, so compare both. See how to read a tyre size.

2. Radial or bias?

Radials win on traction, soil protection and life; bias tyres are cheaper. Never mix constructions on one axle. See radial vs bias.

3. The right tread

R-1W suits most field work; consider R-4 for road-heavy or loader tractors and R-3 for turf. See tread codes.

4. Load index and speed

The new tyre's load index (or PR) should not be lower than the factory tyre's, and its speed symbol must suit the tractor's road speed. See load index and speed symbol.

5. Keep the 4WD ratio

If replacing only fronts or rears, the new outside diameter must be close to the old one or the front–rear ratio changes. See 4WD ratio.

6. Check the date

Look at the DOT date and avoid tyres that sat in storage for a very long time. See tyre age (DOT).

7. Don't forget the rim

Have the rim checked for cracks, dents and rust, and confirm rim width if going wider. See rim width.

8. Replace in pairs

Replacing both tyres on an axle gives equal diameter and traction on both sides. If only one is replaced and wear differs a lot from the other, replace both.