Proof of performance

Surface and depth of the imprint area Surface

How is it done?

A sand track is a means of comparing tires in a highly analytical, reproducible manner, which is difficult to do in the middle of a field due to the  difficulty of controlling the initial condition of the soil, the levels of pre-compaction and humidity. A significant difference between two agricultural tires identified on sand will be reflected in the same way on farm soil.  During the test, several imprints were repeated to ensure high-quality measurement.

What are the results?

The test enables the surface area of imprints and the depth of ruts to be measured.

According to the example opposite, the test showed that the Michelin® XeoBib tire has an imprint 24% larger in area than that of a classic technology tire, as well as a 55% shallower rut depth.

Measurement of ruts and effect on depth

How is it done?

A ditch is dug and then filled with layers of soil of alternate colors. The machine, equipped with the agricultural tires to be tested rolls over this ditch.

After the pass, a trench is dug perpendicular to the tire tracks.  The deformation of the layers of soil can then be measured and analyzed (from a quality and quantity aspect).

What are the results?

This test has enabled us to observe that use of a Michelin^® tire with Ultraflex technology reduced compaction by close to 20% compared with a competitor* tire.

The consequences of ruts and compaction on the quality of the soil are measured by the penetrometry test.

Measurement of soil compaction

How is it done?

The penetrometry test is conducted out in the field.  The machine, fitted with the agricultural tires to be tested, rolls over the   test zone.

After the pass, measurements are taken at various points at regular intervals along the track left by the tire. Soil compaction is measured at different depths with a penetrometer.

What are the results?

These measurements enable compaction of the soil to be measured after the pass of the machine equipped with the tires to be tested.

In the example opposite, after the pass of an agricultural machine equipped with Michelin® CerexBib tires, its quality remains at a level considered as good for the development of roots (see graph – source Wright Resolutions) whereas after the same machine equipped with competitor tires has run over the soil, the limit threshold for good growth of crops is exceeded.

How is it done?

The test is conducted in an actual soil preparation situation and calls for maximum use of the tractor output. On a plot of land with uniform soil the tractor has a tooth plow attached and covers a predetermined distance. The exercise is repeated with the various tires to be compared mounted.

Since the traction effort is identical on each pass, the spin and therefore the fuel consumption, will enable several tire solutions to be differentiated (to refine the test further, an effort sensor installed between the tractor and attached plow permanently measures the traction force).

Consumption mesurement

 Consumption is measured by means of a system set up on the fuel supply circuit.

What are the results?

The comparison of consumption reflects a saving on fuel of up to 25% when MICHELIN Ultraflex technology agricultural tires are mounted. 
         
MICHELIN Ultraflex technology tires are able to function at lower pressures (but still in compliance with our recommendations). This reduction in pressure permits a larger footprint and results in better traction.

Result: a high reduction in the rate of slip and better fuel economy.

How is it done?

The accelerated wear test is based on actual rolling conditions and is carried out without a driver 24 hours a day. The implementation protocol integrates speed variation and the simulation of various kinds of use.

What are the results?

An analysis is made of the condition of the tire tread after the test.

This test enables a very accurate comparison to be made of tires of a different type, range or composition by analyzing the condition of the tread and wear at each point on the  tread.

These results are then consolidated by means of tire usage on farms.