The greater the load, movement or impact, the higher the rate of wear that occurs for the top cover. Increasing or decreasing the top cover thickness is a trade-off between cost vs life. The aim is to provide a suitable wear life of the belt, without excessive cost, before it needs to be replaced.
The thickness of the covers adds or subtracts from the belt mass. The belt mass has an impact on a range of factors which need to be considered in the structural design of the conveyor. For example, frame, idlers and pulleys will need to be adjusted to accommodate the differences in forces a heavier belt will inflict.