Which of the following is NOT a recommended check for the inner side wall of a tire?

The reason the number of visible leaks is not a recommended check for the inner side wall of a tire is that tire inspections generally focus on the physical condition of the tire rather than the presence of air leaks on the inner side. When inspecting the inner side wall, the main concerns are related to its structural integrity and surface condition, which include checking for cuts, bulges, and abrasions—issues that can compromise the tire's performance and safety.

In contrast, while leaks can be problematic, they are typically assessed through other means, such as checking the air pressure or visual inspection of the outer tire for signs of deflation. Thus, the focus is on ensuring there are no physical defects on the inner side wall itself that could lead to failure while driving.