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Newbie question- Can someone explain the "Q-factor" to me?(4 posts)

Newbie question- Can someone explain the "Q-factor" to me?DL Lawrence
Jan 3, 2004 6:52 AM
I've seen this in some crank info and discussion, and I'm afraid I'm not getting exactly what this is. Thanks in advance for your help!
crankarm width..C-40
Jan 3, 2004 7:32 AM
Q-factor is the width between the ouside of the crankarms (where the pedals attach). It varies from just under 150mm on double cranks to around 170mm on MTB cranks.

Some folks experience knee problems if the Q-factor is too large.
one way to measure isjiggs
Jan 3, 2004 12:01 PM
holding bike upright looking at the front, put a ruler on the seat tube and rotate the crank backwards and set the end of the ruler just outside the right crank arm. Than rotate the crank backwards 1/2 turn and read the distance to outside the left crankarm. 6" is 152 cm. (multiply inches x 25.4 to get cm)
Cool! Got it, thanks guys. (nm)DL Lawrence
Jan 3, 2004 3:42 PM