The paper presents results of the research on traction properties of two tractor tyres used on two agricultural grounds. The first ground was a stubble and the second one cropland. The investigated tyres had the same structure (diagonal, with a traditional tyre tread but different external dimensions. The research was carried out in field conditions with the use of a stand aggregated with a farm tractor. Analysis covered traction efficiency, slide, towing power and power lost on the rolling resistance and wheel slide. Based on the obtained results it was concluded that on a ground with lower compaction, the values of power losses were higher and traction efficiency was lower. Moreover, it was proved that the value of the power lost for rolling resistance had a decisive impact on the values of traction efficiency

This paper presents an innovative digital method to analyse agricultural tire profiles based on pictures. From this method, we can conclude that the tire deformation is caused by the changes in vertical load and inflation pressure. The first stage in this method is 3D-scanning; the vertical cross-section is created from the obtained picture of the tested tire. From this cross-section, the deflection of the tire can be determined. Then, the horizontal cross-section is created - this operation allows determining the tire’s contact area at the highest vertical deformation. Obtained results can be useful to create the tire deformation characteristic. In turn, the contact pressure values can be determined (even through laboratory testing, without research in field conditions). The knowledge about contact pressure allows taking some actions to reduce soil compaction. In the description of the method, the radial tire was used, but the structure and equipment of the test bench allow the use of cross-ply tires with different dimensions.

This study presents the results of research related to agriculture tire deformation under variable vertical load and inflation pressure. The research objects were two tires of the same size and different internal structures. Three levels of inflation pressure and five levels of vertical load were used. The loaded tire with each inflation pressure was scanned using the 3D scanner—the effect of this operation was a three-dimensional image of a tire part (near the place of contact with the surface). The next step was the creation of vertical and horizontal cross-sections of the tire profile, which allowed the analysis of tested parameters: profile height, location of the point of maximum tire deflection, the width of the tire profile, and the area of horizontal cross-sections. Finally, the mathematical model was formulated, describing contact areas of horizontal cross-sections as a function of the factors. Based on the conducted research, it was stated that an increase in vertical load caused reductions in both types of heights. Moreover, the width of tire profiles and the area of horizontal cross-sections increased due to the increase in vertical load (for bias-ply, increases were smaller than for radial tires). Similar changes were observed after the reduction of inflation pressure.

This paper presents the results of the measurement of tire footprints in soil. The research was conducted under laboratory conditions using soil-filled cases. The research objects were two tires: a radial tire and a bias-ply tire of the same size. The variable parameters were vertical load (7.8 kN, 15.7 kN, 23.5 kN) and inflation pressure (0.8 bar, 1.6 bar, 2.4 bar). Test benches with a mounted tire, a soil case, and a 3D scanner were used in the research. Using the test bench, a tire was loaded with each inflation pressure, and a tire footprint was generated in the soil. Then, a 3D scanner was used to scan the tire footprint, and the parameters of length, width, depth, and tire–soil contact area (as a spatial image) were evaluated using special software. Then, mathematical models were formulated (separately for each type of tire) to describe the tire–soil contact area of the tire footprint as a function of the vertical load and inflation pressure. It was found that the depth of the tire footprint is an important parameter that influences the tire–soil contact area value. However, it was also found that with the right combination of inflation pressure and vertical load, a longer and wider, but shallower, tire footprint can be generated, the contact area value of which is similar to that of a deeper footprint.

This paper presents an innovative method to determine the impact of agricultural wheels on soil. The experiment was conducted under controlled conditions, and the parameters of the tire footprints on the soil were analyzed. The tested parameters were the width, length, and depth of the footprint, the cross-section area of the tire, and the area of the footprint. All parameters were determined using the 3D scanning method. Two types of tires, two levels of vertical load, and three levels of inflation pressure were used. The aim of the research was to demonstrate differences in changes in the footprint parameters as a result of changes in the operational parameters of the tires. It was found the bias-ply tire was less responsive to changes in the width and length of the footprint than the radial tire. Moreover, it was shown that radial and bias-ply tires achieved similar values for the footprint area but in the case of bias-ply tires, there was a much greater footprint depth. This means that the side parts of the footprint of bias-ply tires have a more vertical profile, so they carry the vertical loads to a lesser extent.