What aspect does not contribute to the optimal meshing of a V-belt?

The length of the belt does not directly contribute to the optimal meshing of a V-belt. While the length of the belt is important for overall fit and functionality in a drive system, it does not influence how well the belt engages with the pulleys. Optimal meshing is more significantly influenced by factors such as proper tension, which ensures that the belt maintains appropriate contact with the pulley surfaces without slippage, and correct alignment, which ensures that the pulleys are properly positioned relative to each other so that the belt can run smoothly.

Additionally, the quality of materials is crucial as it defines wear resistance and the ability to handle the stresses during operation. Hence, the length itself is not a factor that directly affects the rate or quality of engagement with the pulleys, making it the least relevant choice regarding optimal meshing.