Efficiency (%)
Ordinary bearings	95 - 98
Roller bearings	98
Ball bearings	99
Shaft and rigid couplings	Nearly 100
Spur gears with cut teeth including bearings	99
Bevel gears with cut teeth including bearings	98
Cross helical gears	84
Worm gearing	50 -97
Belts	96 - 98
V-belts	95 - 98
Cogged wedge or cogged V-belt	97
Poly V or ribbed belt	96
Synchronous or timing belts	98
High-class silent power transmission chain	97 - 99
Roller chains	95 - 97
Bicycle derailer	87 - 97
Bicycle gear hub	86 - 95
Ball bearing screws	90 - 93
Roller bearing screws	80
Power screws	38 - 84
Screw fasteners	38
External gear pump	85
Internal gear pump	90
Vane pump	85
Radial piston pump	90
Bent axis piston pump	92
Axial piston pump	91
Axial piston hydraulic motors	95
Radial piston hydraulic motors	90
Vane hydraulic motors	85
Gear and orbital hydraulic motors	80
Electrical motors	80 - 92
I.C. Engine	35
Slider crank chain	85 - 90
Four bar linkage	90 - 95