Different-sized tires can
- always be used on the same axle.
- never be used on the same vehicle.
- be dangerous if used on different axles.
- be dangerous if used on the same axle. ✓
Answer: D. be dangerous if used on the same axle.
Different-sized tires can be dangerous if used on the same axle.
Why this is the answer
The handbook lists a mixture of different sizes, or a mix of radial and bias-ply tires, on the same axle as a common tire problem. It notes that mixing is possible on the same vehicle but not on the same axle, and adds that this is not a recommended practice. Because the handbook puts this in its list of tire problems to check for, the safe answer is that mismatched sizes on one axle can be dangerous.
Why the other answers are wrong
- A. always be used on the same axle. — The handbook says different sizes should not be used on the same axle, so saying they can always be used there is the opposite of its advice.
- B. never be used on the same vehicle. — The handbook says different sizes can be mixed on the same vehicle, just not on the same axle, so a blanket ban on one vehicle is too broad.
- C. be dangerous if used on different axles. — The handbook's warning is about mixing sizes on the same axle, and it allows mixing on the same vehicle, so it does not say different axles are the danger.
Remember it
Picture the axle, not the whole truck: the handbook's tire-size warning points at one axle at a time.