What can be a consequence of over-tightening a belt?

Over-tightening a belt can lead to premature bearing failure because excessive tension places additional stress on the bearings of the motor or equipment connected by the belt. The bearings are designed to handle a specific load within certain tolerances; when the load exceeds those tolerances due to the tightened belt, it can cause increased friction and wear. This friction not only generates heat but can also lead to the misalignment of parts, further exacerbating wear and ultimately leading to the bearings failing sooner than expected.

The other options do not align with the effects of over-tightening. For instance, over-tightening does not correlate with reduced energy consumption or improved efficiency, as it can actually increase the load on motors and lead to inefficiencies. Similarly, rather than lowering operational costs, the need for repairs or replacements caused by bearing failure will likely increase them.