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Q factor?(10 posts)

Q factor?Wagnerite
Apr 22, 2002 9:53 PM
been pretty busy with school lately, having not much time to ride.

here's the problem. I think when I'm on the bike, my feet are too close together. Everything on my bike is great, fitment wise. Bar reach is fine, derailers are function correctly, seat is ok, but my feet are too close together.

is there anythingi can do to bring the pedals further away from each other?

thanks in advance.
re: Q factor?xxl
Apr 23, 2002 2:07 AM
Wow, most people complain their Q-factor is too high. But, if it doesn't feel right to you, try moving your cleats on your shoes all the way to the inside (towards your insteps). If you've done this already, or happen to like your cleat setup, then there's the bottom bracket; you could get a longer spindle. Of course, you'll need to consider the effect of this on chainline. Another fix would be to get pedals with longer spindles (don't know what they are, sorry). After that, you've got only the crankset left, and most modern options strive to be low-profile, with minimal variations in effective "Q." One "solution" might be to use an older crankset, but that's not for everybody.

Out of curiosity, what exactly is it that you feel about your feet being too close together? What I mean is, are you getting knee pain, ankle pain, or what?
Unique complaint in the history of bicycling?retro
Apr 23, 2002 6:41 AM
xxl's right--that's a really unusual complaint. Nearly every framebuilder who really knows his stuff has worked on getting the Q factor DOWN, for a number of physiological reasons. A longer BB spindle would be a pretty easy fix. Like xxl, though, I'm curious about what makes you think that's the problem (I'm not saying it isn't--I just can't even imagine what it would feel like).
Unique complaint in the history of bicycling?gtx
Apr 23, 2002 7:39 AM
longer bb spindle would mess up his chainline. Different cranks (with the appropriate bb) or pedals might increase the q factor. But I think his problem is "not much time to ride." When you don't ride much, you're bike can feel odd or wrong.
Not unique at all.djg
Apr 23, 2002 9:04 AM
Pruitt's medical guide for cyclists addresses just this point, as does--in a mechanical sense--Look's CX7 pedal (adjustable Q factor and adjustable cant precisely because not everybody profits from the stock solution, let alone the narrowest possible set-up--in fact, many people have different needs from one leg to the other). I mean, if you're smooth and comfortable as is--cool. But not everybody is. (Incidentally, I've seen the "physiological" explanation for minimizing Q factor--or at least one of them--and it seemed ridiculous on its face).
re: Q factor?Justride
Apr 23, 2002 8:08 AM
I discovered a product called Kneesavers while looking for ways to help lower the stress on my arthritic knee. They are devises that extend Q-factor by 20mm. You screw them into the crank arm and the pedal into them. They were developed by a physical therapist that claims that they can help people with wide hips or people that walk with a toe out posture find relief from cycling related knee pain that may be associated with these conditions. I posted a thread on this site to see if anyone had experience with them and recieved only one response that stated they were helpful without much detail. I have not tried them yet.

I know the conventional wisdom is to lower Q-factor but I wonder about people that do not fit the "average" cyclist body profile. If someone has wide hips will they be as comfortable and produce the same power as a narrow hipped person riding with the same Q-factor? Why has Look introduced a pedal with adjustable Q-factor if it should be as low as possible for all riders? It does make a certain ammount of sense to me that just as people need different width bars they may need a wider or narrower Q-factor to accomodate their physical structure.

I would love to hear about this from a bike fit expert or frame builder if any of them that read this group would like to comment. I think it would be very enlightening.
Photo and urlJustride
Apr 23, 2002 8:13 AM
http://www.bikescor.com/product/knee.htm
Knee saversChaz_cycles
Apr 23, 2002 8:39 AM
I have a friend who uses these when he rides anything less then a triple. He had terrible knee trouble until he found this product and they have seemed to fix his problem.
I have a question...PsyDad
Apr 23, 2002 9:38 AM
Did Shimano decrease their spindle length to address the Q-factor? A number of years ago, I was using Ultegra (square taper) with a 113mm BB cartridge. Now, Shimano has the new splined BB's with a 109.5mm for a double and then I think the next one up is 116mm? Also, some have stated that if they put on a 42 on the inner chainring with the 109.5 that they have 1-2mm of clearance. One guy in Florida said that the grains of sand actually wore that area when he was using a 42.
Maybe some answersKerry
Apr 23, 2002 5:37 PM
First, when they shortened the spindle by 3.5 mm, they probably didn't narrow the Q by that much. More likely they shortened the spindle to save weight and increase stiffness, and then changed the crank arms to put the pedals back in the same place. This could be done by changing the depth of insertion on the BB axle, or by changing the angle of the crank arm. I've not heard that the Q on S cranks has changed, though it may have. You'd think if it had, somebody would have been talking about it. The rubbing on the chain stays could just as easily be because the bikes have fatter chain stays - thin walls/light tubing = larger diameter to maintain stiffness.