The answer options
- 2mm
- 1mm
- 2.2mm
- 1.6mmCorrect
Why that is the answer
The legal minimum tyre tread depth for a trailer towing up to 3,500 kg is 1.6 mm. This standard applies to car tyres as well, and the tread must cover the central three-quarters of the tyre's breadth around the entire outer circumference. Towing with worn tyres drastically reduces grip and increases stopping distances in the wet. While 1 mm is the legal limit for motorcycles, it is unsafe and illegal for trailers.
How this comes up in the real test
Questions from vehicle loading appear throughout the 50-question multiple-choice section, and the wording changes between versions. Learn the rule rather than the sentence: the DVSA can ask the same point from the opposite direction, and a memorised answer falls over the moment the phrasing moves.
The pass mark is 43 out of 50, so seven wrong answers is your entire margin. If a whole category is shaky, run the topic practice below until you are getting every question right for the right reason, then go back to full mocks under the clock.
More vehicle loading questions
- A trailer braking system must have a safety device fitted. What is this device?
- A vehicle should never be overloaded. Who is responsible for ensuring this?
- Are passenger allowed to travel in a caravan when been towed?
- How will the handling of your car change if you have a large load on your roof rack?
- Sometimes you may need to increase your tyre pressure to above the normal value. When would this be necessary?
- What is the maximum authorised mass (MAM) you can tow in any trailer, having just passed your driving test?