An acceptable out of round cylinder is a cylindrical shaped object that has become slightly distorted from its original shape due to use or wear over time. This distortion can often be seen in cylinders used as part of engines, machines and other mechanical equipment. Out of round cylinders typically have walls that are thicker on one side than the other and may appear slightly flattened or misshapen when viewed in cross-section. While some out of round cylinders may not present any significant performance issues, others may lead to decreased efficiency or even damage if left unchecked. To ensure proper functioning, it is important to regularly inspect all components for signs of uneven wear and replace them with new parts where necessary.