I'm revising for the UK LGV theory test. One of the questions goes something like this:
Which axle configuration is most effective at preventing petrol tankers from rolling over?
- A. Tandem axles with double wheels
- B. Tandem axles with air suspension
- C. Tri-axles with single wheels
- D. Tri-axles with double wheels
The correct answer is apparently C, with the following explanation:
The type of suspension fitted to a vehicle will influence its resistance to ‘roll-over’. Modern tri-axle semi-trailers fitted with single wheels on each side extend the tracking width available, making this the most stable configuration.
I have the following questions:
- Why are single wheels better than double wheels?
- Is this specific to a tri-axle setup, or does it also apply to twin-axles or single-axles?
- Is this specific to trailers, or does this apply to rigid vehicles as well?
- If single wheels are better, why do so many vehicles have double-wheels?