**Q-Factor**  

This is the distance (in millimetres) between the outside faces of your crank arms.  Effectively, a larger Q factor means your pedals are further away from the bike's center line, and therefore your feet are further apart.

A narrow Q-Factor is considered more aerodynamic, but increases the risk of chaffing the inner thigh on the nose of your saddle.  Likewise a wide Q factor means your knees and thighs are opened up, which may help joint comfort.  Going too wide will make joints painful.

Q-factor can be increased by adding extenders, or using pedals that have longer shafts.

[![enter image description here][1]][1]

A pedal with an extender added.  Imagine that screwed into your crank - the pedal will end up further "outboard" from the bike's centerline.

Q-factor can only be reduced by changing the cranks for narrower ones, which increases the possibility of heel/shoe strike on the crankset or chain or front derailleur.

Note - q factor is NOT measured from the centerline because it could be different on each side.

[![https://electricbikereview.com/forum/attachments/bicycle-q-factor-jpg.21791/][2]][2]


  [1]: https://i.sstatic.net/Kv4Dq.png
  [2]: https://i.sstatic.net/Glvp9.jpg