Remind me. Why is low Q factor good?

[vqdriver]

Maybe I just don't get biomechanics or whatever. I would have thought that it's another "every person fits differently" thing. But not so much.

[donevwil]

I tend to agree with you, it's an individual issue with no standard for all. Some think Q-factor should mimic walking or running stride width for greatest efficiency, but every body is different and we're typically talking 3, 5, 10mm differences with Q's, not that much.

I am, or my hips more specifically, are very sensitive to Q-factor. Not narrow necessarily, but I have to exist within a tight range or my hips will howl after only a few miles. New MTB triples are a no-go for me. That said on very low Q cranksets, like old Ritchey Logics, I actually need to use a 3-5mm wider BB for best results.

[witcombusa]

Agree. The important number is one that works for you. Saying narrow(er) is best is just plain false. Some people seem to be more sensitive to this than others. I have bikes with a huge range of Q's and honestly don't have any that are not comfortable for me.

[aaronf]

A potential benefit for narrower would be that you can more easily adjust your stance to wider via spacers or longer pedal spindles. Can't really make a crank narrower once it's too wide.
But for sure, narrower is not necessarily always better from the biomechanic standpoint.

[Climb01742]

Agree, it's very personal. If I go wider, my hips scream. Very sensitive to even small variations.

[Bradford]

I prefer a wider Q. For a while, I had a narrow Q double on my Legend and triples on my touring bike and tandem. The narrow Q drove me nuts every time I got on that bike. Now all three bikes are set up the same and feels much better.

I'm a big guy for a cyclist, have a naturally wide stance, and assume that has something to do with my preferences.

[93legendti]

Agree, it's very personal. If I go wider, my hips scream. Very sensitive to even small variations.

Same here. Triple cranks irritate my right leg's IT.

[Climb01742]

Same here. Triple cranks irritate my right leg's IT.

Precisely. Even going from a Shimano double to the wider SRAM double tweaks my hips and IT bands. Triples are torture.

I don't know whether it's biomechanical or just what my body has grown accustomed to, but man, even a few silly mm's can really make my hips scream.

[93legendti]

Precisely. Even going from a Shimano double to the wider SRAM double tweaks my hips and IT bands. Triples are torture.

I don't know whether it's biomechanical or just what my body has grown accustomed to, but man, even a few silly mm's can really make my hips scream.
I have never tried a SRAM Crank. I think I will avoid them-thanks for the heads up.
I can blame my lousy flexibility. My right leg has decreased flexibility due to a broken femur and subsequent operation. I also think my hips are narrower so a low Q lets me drive the pedal down, where as a wider Q seems to be driving out and down. Ouch.

Luckily, there are choices.

[Bstone]

Q-Factor has to fit within the overall bike fit equation. Like any other factor, it has to be considered as a part of the whole.

I'm short. Classic ectomorph with narrow shoulders. 155 pounds. Therefore my stance is also narrower, thus a more narrow Q-factor. I have good hip and knee alignment. My fit on the bike reflects this.

At a greater Q-factor, the articular surfaces (joint) of my femor and tib/fib would have to be out of alignment and further from the ideal angle to each other. Compare this to the angle that they would be aligned to each other when walking.

Compare that to a big guy (mesomorph) with long legs. As Q-factor increases, his knee joint angle is affected less.

By the way, Grant Peterson, marketing genius that he was, used this idea to sell Bridgestones. Probably not the be all /end all that people make it out to be. But when you are selling a commodity item, anything that you can do to make yours appear to stand out is worthwhile.

[Coluber42]

I have had knee issues in short order from a wide q-factor. Narrow is what I need, although as long as it's within a certain amount (MTB triples are out of the question, and so are some modern doubles depending on BB spindle length) it doesn't seem to matter how narrow. In some cases I can compensate by moving my cleats all the way to the outside, but that's not always possible or good enough.

My better half is about half an inch shorter than me, but with much shorter legs, and he prefers a wide q-factor.

I've known other people who don't notice it at all, and have huge variations in q-factor between their various bikes and they don't care. So I think it falls under "YMMV".

[bluesea]

Oh wow. The knee area injuries that took me out for 15 years, was after 3 years on mtb's almost exclusively. Even now I've been off road bikes since July, and have had issues with a super tight left ITB and also some irritation in that knee.

[Ralph]

I ride two bikes, with a Campy Centaur square taper double and a Record square taper triple. The triple Q is about 10 MM more than the double, so with the long bolts of Keo 11 pedals, I run 2 (.5) mm pedal washers on each side on the double. I get along OK with these different Q cranks, no problems.

But....some things I have learned that's true for me. On the triple, I have to run slightly more saddle height than the double, or the outside of my knees hurt. It's the kind of pain one gets when the saddle is too low. How much does Q (I'm 5' 10") affect leg length from saddle?

Another thing.....my very hi quality Record triple is exactly the same amount from bike center on both sides. My double is not that perfect, so I run a slight .5 MM spacer on the drive side. I measure all this stuff. Most triple cranks I've used in the past, IE wide Q cranks, are not equal on both sides. On most that I have measured, the drive side sticks out a couple MM more than the non drive side. On me, this would cause a problem in a knee. From one side being too high or too low.....or "out" too much. So I no longer assume cranksets are equal both sides, or the BB shell sits correct in frame. I think it's important that "Q" be the same both sides and leg length be the same both sides. Also account for pronation with a shim, if that affects leg length. Also 135 MM rear frames would have more Q, and hopefully drive side not kicked out to get proper chainline on that side. It never hurts to measure....or maybe us old guys have too much time on our hands. So yes....Q matters.....but I think there is more to it than just "what is the Q"? Does your crankset with narrow 145 MM Q, have 72.5 of that on each side? Or the triple road crank with 155 Q have equal amount each side?