Improving traction: which tractor tires should you use?
What is traction capacity?
Traction capacity comes into play when the tractor needs to shift power, particularly because of a high rear load exerted by a towed farm implement. Difficult conditions such as soft, wet ground can worsen this need, resulting in a high rate of slippage.
Tractor Slippage
As you know, it is common and normal for tractor tires to slip a little when working in the field. If the slip rate were zero, you might think that the tractor's effort was not being fully maximized and that productivity needed to be improved.
But above a certain threshold, slippage indicates insufficient power in the drive axles, and a need to optimize traction.
What is an acceptable tractor slippage threshold?
Generally, acceptable slippage is between 8% and 15%.
Take action to reduce slippage if it exceeds 15%.
Above 20%, slippage becomes an alarming sign, implying a loss of productivity, and requires urgent attention and solutions.
What causes excessive slippage?
Some towed tractor implements require more effort from the tractor than others. Large tractor attachments like plows or wide cultivators can be hard to pull. Stubble cultivation tools can also require more pulling power because they have tines that work at greater depth than those with discs.
How to optimize traction for your needs?
1 - Tractor Ballast
Insufficient traction, highlighted by slippage, can mean that the tractor is too light for the attachment it is towing. This is why, unless the towed implement is replaced by a more compatible one, it may be necessary to ballast the tractor by adding weights to the wheels or to the tires, for example.
2 - Optimize tire pressure
Tire pressure is a crucial parameter in optimizing traction. The lower the tractor tire pressure, the greater the footprint along the length of the tire. And the larger the footprint, the more grip the lugs have in the ground, which in turn reduces the slippage rate.
Adjust a tractor tire's air pressure frequently based on the tractor's load and speed. If in doubt, you can use our "Michelin Agropressure" tool, which will help you find the right pressure in just a few clicks.
Here's an example using a load of approximately 17,400 lbs (7,900 kg) or about 8,700 lbs per rear wheel:
At 40 mph, the tire must be inflated to 1.4 bars for a Michelin Multibib 650/65R42 158D TL. Thanks to Michelin UltraFlex technology, a Michelin Axiobib 2 VF 650/65R42 174D/171E TL going the same speed should be inflated to 0.9 bars.
With Very High Flexion certification, the pressure can decrease by 40% for the same size. This results in a larger footprint for improved traction.*
Several studies** (in the United States, Brazil and England) have established that the use of Michelin UltraFlex technology tires throughout the agricultural cycle improves crop yield from 2% to 6% per year.
Another advantage of low tractor tire pressure is a reduction in soil compaction, which means greater respect for the soil and for earthworms, which are invaluable for their natural role in aerating the soil. The more pores the soil has, the more it can “breathe” and the easier water can infiltrate deep into the soil, resulting in better crop yield.
3- Opt for the Central Tire Inflation System (CTIS)
Navigating tire pressure when dealing with varying terrain is one of the biggest difficulties you’ll face with your tractor. Your load and speed vary depending on whether your tractor is on the road, in the fields, and with or without implements behind it. Your tractor tires need to account for all of these variables. But how do you adjust the pressure each time you use your tractor for a different purpose?
Thanks to the CTIS , you don't need to move from your seat to make tire pressure adjustments.
Your tire pressure will adapt to each variable, which will help reduce your fuel consumption and extend the life of your tractor tires.
How does remote inflation work? Check out this video to learn more
4 - Opt for twinning
Twinning (coupling two tractor tires on the same axle) is another option for optimizing your traction as it naturally increases your tractor's footprint, giving you two main advantages:
- Use more tractor power,
- Lower the tire pressure, which in turn respects the soil more and improves your overall productivity (even with the same load)
To successfully pair tires on the same axle, it’s important that the tires used are identical, have similar wear and us the same tire pressure.
5 - Fit the correct tractor tires
For optimum traction, we recommend the use of Michelin UltraFlex technology tractor tires. They all have the VF (Very High Flexion) or IF (Improved Flexion) standard, which means "low pressure." This low pressure should allow them to reduce pressure by 40%* (or by 20% with the IF standard***) compared with a standard technology tire.
Michelin UltraFlex technology has an advantage over brands by allowing you to make pressure changes over time.
If you also use a CTIS , you can optimize your tractor tires’ pressure both in the field and on the road, which optimizes your fuel consumption and helps you reduce costs.
It's also important to note that we have a Michelin UltraFlex solution for the entire ag cultivation cycle. In other words, we have low-pressure tractor tires for high- and medium-horsepower tractors, combine harvesters, self-propelled or trailed sprayers and trailers.
Need help choosing the right tractor tires? Follow this link:
Need more advice? Discover our tire buying guide.
* Normative gap compared to non VF (Very High Flexion) tire.
** A study carried out by Harper Adams University in the UK from 2013 to 2017, demonstrates that Michelin UltraFlex technology increases agronomic yields from 2 to 6%. These results are confirmed by similar studies carried out in the United States (Illinois) in 2015 and Brazil (Mato Grosso) from 2018 to 2021.
*** Normative gap between standard tire vs VF (Very high Flexion) tire
