What is the main disadvantage of sleeve bearings?

Sleeve bearings primarily utilize a lubricating film of oil between the shaft and bearing surface, which is essential for reducing friction and wear. One of the main disadvantages is that they require regular maintenance, specifically the constant application of oil to ensure proper operation. If the lubrication is insufficient, the bearings can wear out rapidly due to increased friction, leading to operational failures. This necessity for continual lubrication can be a significant drawback, especially in environments where maintenance may be challenging or infrequent.

While other options highlight potential concerns with sleeve bearings, such as noise, overheating, or costs associated with replacement, the critical issue of ongoing lubrication directly affects the reliability and longevity of sleeve bearings, making it a more significant disadvantage compared to the others. In summary, their dependence on regular oiling is vital for optimal function and longevity, thus presenting a key drawback in their use.