Tires: the only contact between tractor and ground
A 6-ton tractor is only useful if its power reaches the ground. Tires are the critical interface — over-inflated, you compact the soil and spin. Under-inflated, you wear the sidewalls and burn more fuel.
Recommended pressures: key references
Pressures depend on load, speed, and work type. Here are typical ranges for a 100-150 HP tractor:
Front tires (steering):
- Road: 1.6-2.0 bar
- Field: 1.2-1.6 bar
- With loaded front loader: 1.8-2.4 bar
Rear tires (drive):
- Road: 1.2-1.6 bar
- Field (plowing): 0.8-1.2 bar
- Heavy transport: 1.4-1.8 bar
These values are indicative. Exact pressure depends on the tire (size, load index, technology) and actual load. Check the manufacturer's inflation table.
The golden rule: the lowest pressure compatible with the load. Every extra 0.2 bar means more compaction and less grip.
Water ballasting: why and how
Filling rear tires with water (water + antifreeze mix in winter) adds weight to the drive axle. It improves traction without adding mass to the tractor frame (unlike metal weights).
Recommended fill rate: 75% of tire volume. Beyond that, the tire loses flexibility and no longer acts as a cushion.
Weight calculation (example 520/85R38 tire):
- Internal volume approximately 500 liters
- 75% = 375 liters of water = 375 kg per tire
- On 2 rear tires = 750 kg additional
Advantages:
- Low center of gravity (more stable than a hitch weight)
- No investment (just water + antifreeze)
- Increases traction by 15-25% in slippery conditions
Disadvantage: permanent weight, even when you don't need it (road). Modern solutions (central tire inflation, IF/VF) may be preferable.
Lug wear: when to change?
New tractor tire lugs are typically 45-65 mm tall. The legal wear limit for agricultural use is 20% of original height.
Signs it's time to change:
- Lugs < 15 mm tall → greatly reduced grip
- Asymmetric lugs (one side more worn) → alignment issue or improper pressure
- Sidewall cracks → rubber aging (UV exposure, age > 10 years)
- Bulge → structural damage, immediate replacement
An agricultural tire costs 500-2,500 euros depending on size. A worn tire that spins makes you burn 15-30% more fuel in the field. The math is quick.
IF and VF technologies: the low-pressure revolution
IF (Improved Flexion) and VF (Very High Flexion) technologies allow running at significantly lower pressures than standard tires at the same load.
- IF: supports the same load as standard with 20% less pressure
- VF: supports the same load with 40% less pressure
Real example:
- Standard 650/65R42 at 1.2 bar for 4,500 kg
- IF 650/65R42 at 0.96 bar for 4,500 kg (footprint +20%)
- VF 650/65R42 at 0.72 bar for 4,500 kg (footprint +40%)
Benefits:
- Reduced soil compaction (better crop yields long-term)
- Larger contact area → better traction → less slippage
- Less fuel consumption in the field (5-15% according to studies)
Disadvantage: 20-40% higher price than standard. But ROI comes within 2-3 seasons through fuel savings and yield improvement.
Central tire inflation: the ultimate solution
Central tire inflation systems allow adjusting pressure from the cab, while driving. High pressure for road, low for field, without stopping.
It's the most profitable investment in tractor tires, but also the most expensive (3,000-8,000 euros for the system).
Try L'Atelier free for 10 days — no credit card required. Find recommended pressures and tire sizes for your model.
