Which statement best describes when slippage marks are required?

Which statement best describes when slippage marks are required?

• A. Only for tubed tires
• B. Only for low-pressure tires
• C. Tires with tubes or tires 150 psi or less require marks
• D. Slippage marks are optional for all tires

Answer: (C)

Slippage marks are used to detect movement between the tire and wheel during mounting, service, or inflation. The requirement applies to tires that have an inner tube or tires that are 150 psi or less, because those types are more prone to slipping on the wheel bead or rotating relative to the wheel. By placing matching marks on both the tire and the wheel, you have a clear reference to see if the tire has moved after installation or during operation. If the marks no longer align, it indicates slippage, which can lead to bead seating problems or tire failure, and prompts corrective action such as re-seating or re-marking. This describes why the rule is stated that way: it covers the situations where slippage is more likely and needs monitoring, whereas high-pressure tubeless tires aren’t included by this particular requirement, and a general statement that marks are optional is not true.

Slippage marks are used to detect movement between the tire and wheel during mounting, service, or inflation. The requirement applies to tires that have an inner tube or tires that are 150 psi or less, because those types are more prone to slipping on the wheel bead or rotating relative to the wheel. By placing matching marks on both the tire and the wheel, you have a clear reference to see if the tire has moved after installation or during operation. If the marks no longer align, it indicates slippage, which can lead to bead seating problems or tire failure, and prompts corrective action such as re-seating or re-marking.

This describes why the rule is stated that way: it covers the situations where slippage is more likely and needs monitoring, whereas high-pressure tubeless tires aren’t included by this particular requirement, and a general statement that marks are optional is not true.