The Q factor or quack factor of a bicycle is the distance between the pedal attachment points on the crank arms, when measured parallel to the bottom bracket axle. It may also be referred to as the "tread" of the crankset.
The Q factor is an important factor affecting how close the pedals are laterally, and therefore the affects the spread of the riders legs
The quack factor is a reference to the wide-stance gait of ducks - the larger the stance, the larger the quack factor
The bottom bracket on a bicycle connects the crankset (chainset) to the bicycle and allows the crankset to rotate freely. It contains a spindle to which the crankset attaches, and the bearings that allow the spindle and crankset to rotate. The chainrings and pedals attach to the cranks. Bottom bracket bearings fit inside the bottom bracket shell, which connects the seat tube, down tube and chain stays as part of the bicycle frame.
Aerozine ceramic external bottom bracket bearing cups for BSC/ISO standard, that is M34.798×1.058 mm (1.37″-24 TPI) threads and a 68 mm wide bottom bracket shell
Plain bottom bracket shell of Royal Enfield Revelation houses Bayliss Wiley unit bottom bracket
Bayliss Wiley unit bottom bracket
Thompson bottom bracket
