# 5.1 Nature and condition of the ground

The nature and condition of the ground and the presence of any obstacles will havean influence on choosing the right wheel. They are also important factors affecting the performance of the moving equipment as well as the efficiency and the duration of the wheels and castors.

Special attention is required for cases involving uneven floors or where obstacles are present. In this case, the impact of the wheel against an obstacle generates advancement resistance whose magnitude depends on the elasticity of the rolling strip material. In fact, the energy absorbed during an impact is greater in a wheel with an elastic rolling strip than in a rigid wheel, thus partially cancelling the braking effects caused by the obstacle.

For floors that are uneven or on which obstacles are present, with load capacity being equal, a wheel with a greater diameter should be chosen in order to overcome the obstacle.
The wheel must be chosen very carefully in all cases in which there are obstacles, chemical and/or organic substances and machining residues. The main types of flooring are:

• tiles;
• asphalt;
• cement-resin;
• not paved floor;
• expanded metal floor;
• floor with chips, obstacles etc.

The main floor-wheel covering combinations are listed in the following table.