Idler-wheel
（重定向自Idler pulley）
![Gears in a machine. The middle, medium-sized gear is an idler gear.](/Images/godic/202501/19/Gears_large5111.jpg")
An idler-wheel drive is a system used to transmit the rotation of the main shaft of a motor to another rotating device, for example the platter of a record-reproducing turntable or the crankshaft-to-camshaft gear train of an automobile.