When should you not turn on the front wheel drive of an agricultural tractor?
Show the correct answer
Correct answer
A. When driving on a paved road, unless it is necessary to overcome temporary resistance.
Explanation
This question is about situations in which you should not switch on the front-wheel drive of an agricultural tractor. You do not switch it on when driving on a hard road, unless you need to overcome temporary resistance - answer A.
With the drive engaged, the front wheels deliberately turn slightly faster than the speed of the tractor would require, and on bends they follow a longer arc than the rear wheels. In many tractors the front drive is rigidly connected to the rear drive, so on a hard surface with good grip these differences have no outlet: the tyres wear, the drive system is overloaded and fuel consumption increases. On boggy terrain (answer C) the tyres can slip slightly, and the front drive then provides the necessary pulling power. When the rear wheels are skidding (answer B), the front drive helps to regain traction. On the road you switch it on briefly, for example when moving off uphill with a heavy trailer, and switch it off once the obstacle has been overcome.
Legal basis: Art. 19 para. 1 of the Road Traffic Act (Prawo o ruchu drogowym) (the principle of keeping control of the vehicle); operating rules from the tractor's owner's manual