Gear wear detection in intermeshing running gears

A pair of intermeshing preferably oil-free running gears in particular for dual- or multi-shaft vacuum pumps, comprising a first running gear and a second running gear,

• characterized in that
• at least the first running gear comprises a first gearwheel and a second gearwheel,
• wherein the first gearwheel and the second gearwheel are axially arranged, and
• wherein the first gearwheel comprises a predetermined number of first cogs of same dimension and the second gearwheel comprises a predetermined number of second cogs, wherein the predetermined number of second cogs is at least one, and
• the predetermined number of second cogs have a dimension smaller than the dimension of the predetermined number of first cogs to a predetermined amount,
• wherein the first gearwheel is made of a material with a first elastic modulus and the second gearwheel is made of a material with a second elastic modulus, and the first elastic modulus and the second elastic modulus are different.