Leonardo da Vinci designed an early ball bearing to reduce friction between moving parts.
His notebooks from around 1498 show balls arranged so that they could roll between components instead of allowing surfaces to slide directly against one another. This arrangement addressed a basic engineering problem: sliding contact creates substantial friction, while rolling contact can make movement easier.
Leonardo’s drawing is an important early example of the ball-bearing principle, but it was not a complete modern bearing with standardized races, seals, and precision manufacturing. Renaissance workshops lacked the industrial production methods needed to make large quantities of accurate, durable bearings.
Modern ball bearings became practical much later as metalworking and manufacturing improved. Leonardo therefore did not invent every feature of the contemporary bearing, but his design clearly anticipated the central rolling-element idea.