I wonder how much of that is learned/adapted or can be adjusted by fit (perhaps more (or less) cant/tilt of the foot.

just thinking out loud really but you're probably roughly similar age to me. I grew up riding/racing road bikes 7spd downtube shifters and my quick googles shows that the rear dropouts were 126mm. no clue on the Q factor. Does years and years (or hours) of riding a narrow q factor affect how I ride now? Will my son (riding 156mm on his current bike) be able to adapt better to newer standards like the boost spacing (168 or whatever)?

fwiw, I don't seem to have a problem with the new spacing (yet) but only recently have switched all my mtbs to boost spacing.

lots to ponder.

 

I wonder how much of that is learned/adapted or can be adjusted by fit (perhaps more (or less) cant/tilt of the foot.

That's an interesting idea. I don't recall that adjustment being made or investigated in the referenced work. I certainly haven't changed canting or anything consciously. I regularly ride 3 bikes with 3 different Q-factors (142, 149, 168) with the same shoes and make of pedals with out making any adjustment -- maybe I should...

I grew up riding/racing road bikes 7spd downtube shifters and my quick googles shows that the rear dropouts were 126mm. no clue on the Q factor.

My Raleigh Professional, circa 1978, has the rear dropout spacing of 126 mm for it's 6 speed cluster and the Q-factor on the Campagnolo Nuovo Record crank is 135 mm. My current CX/gravel/road bike has an octalink bottom bracket with Ritchey WCS cranks and has a Q of 142 mm. My daugther's Ultegra compact crank with an integrated spindle has a Q-factor of 145 mm.

Does years and years (or hours) of riding a narrow q factor affect how I ride now? Will my son (riding 156mm on his current bike) be able to adapt better to newer standards like the boost spacing (168 or whatever)?

Several of the studies that are described in the linked document allowed trained cyclists (presumably years/hours of riding) self select their own Q-factor on a specially designed lab setup and they picked different (narrower) than their road setup. So, I'd guess that it's less about what you're use to and more about what your (and most people's) physiology would prefer.

fwiw, I don't seem to have a problem with the new spacing (yet) but only recently have switched all my mtbs to boost spacing.

So as we increase our tread width, would we notice a reduction in power? Or do we only think in terms of "no joint problems, so it's all good"?

 

The studies regarding low Q have been primarily concerned with aerodynamics where lower Q is more aero.

I started with road racing in 1981 and believed for the longest time that lower Q was better, although at that time for singlespeed/fixed gear no clips on flat pedals (i.e. unicycle riding) that for max cadence my feet would migrate wider.

During the 1990s I became an NCCP Level 2 MTB Coach, and began doing bike fits and using myself as a guinea pig to test foot beds and wedges (in addition to taking part in a university research program on mtn bike shoes). I discovered that somehow I couldn't get my knees narrow and maintain good knee tracking.
Further experimentation occurred after I tore an ACL in 1995, and I just gave up on the ultra narrow Q and narrow knee spacing.

In 2016, I spent 3 weeks in Arizona training long days in the saddle for the AZTR bikepack race, while breaking in new shoes and cleat placement, and discovered that by paying attention to knee tracking and signs of discomfort that my Q widened so that my limbs and feet where stacked inline under my hip sockets. With that even wider (natural width spacing) I had no knee discomfort racing the AZTR 750.

Maybe for high torque mtn biking, or the feeling that wider stance is better for lateral balance and/or shock absorption off-road, natural Q is better than narrow Q for many riders?

 

and discovered that by paying attention to knee tracking and signs of discomfort that my Q widened so that my limbs and feet where stacked inline under my hip sockets.

+1 on that.

 

Maybe 10 years ago did a lot of playing with Q factor. Lots of time in machine shops modifying (destroying) cranks.

In the end when we put everything on and tested it there was zero difference in performance.

 

Just a personal observation. I rode a reasonably narrow Q for decades. Now I ride flats with a wide Q and I no longer have knee pain. I addition I find my foot migrating out further on the pedal. I often look down to find my left foot an inch from the spindle nut wrench flats. I wouldn't "self select" a wide Q with no experience with wide ones, but I would now knowing the comfort it brings.

 

^Ptor
I was referencing Q studies in my above post that were conducted prior to the ones you linked
I read quickly through most of your link
I didn't catch if the linked studies were double blind
Anyway power and efficiency differences were "not significant" (pages 76, 90 and 103)

Out in the real world there is lots of anecdotal evidence of riders self selecting wider Q.
I think on my unicycle at high cadence I need to move my feet wider to provide better yaw axis and roll axis stability

One thought is that the linked studies were conducted on stationary bikes, where the riders would not have to stabilize their bodies or the bikes. I wonder if the studies were conducted with rollers, if riders would self select wider than a stationary bike?
Also, as with many other studies, athletes tend to be more efficient at close to what they are trained and adapted to. Maybe compare mtn bikers with track riders, to see if there is a difference?

Don't give up on your Element. If you really want less Q, there is lots of space between the cranks and the chain stays. The frame is stiff enough that only a few mm clearance is good enough (you might have to off-set chainrings with different spiders if you choose a narrower spindle to maintain a good chainline. However, I think chainline biased towards your climbing cogs might be better for drive train life)

 

Don't give up on your Element. If you really want less Q, there is lots of space between the cranks and the chain stays. The frame is stiff enough that only a few mm clearance is good enough (you might have to off-set chainrings with different spiders if you choose a narrower spindle to maintain a good chainline. However, I think chainline biased towards your climbing cogs might be better for drive train life)

This statement stuck with me and prodded me into action. I had a Scott Scale with a 156 mm Q factor XX1 crank so I swapped the cranks between the Element and the Scott. I also had to swap the rings and spacers as the Element is Boost and the Scale is not. It turns out that the 168 and 156 XX1 cranks have the same spindle lengths but different arms -- more flared on the 168mm crank. I was even able to put the crankarm boots on and have plenty of chainstay clearance with the narrower Q-crank on the Element (lots more pedal/crankarm strikes as I pedal through the rough stuff on a full suspension). I'd been getting hip pain from spin and exercise bikes at the gym (crappy spring weather) and I surmised it was from the fat-bike-like large Q-factor cranks. I won't claim I get more power to the pedals dropping the Q by 12 mm, but I am more comfortable.

I also clipped a picture from an article linked by LMN in the thread "A good read" of Annika hitting 999 watts in a sprint. This sort of position on a bike (also the position you get when climbing out of the saddle) has been in my mind for years as an example of how people naturally end up putting power down using a reduced Q-factor power-stroke.

 

I'd say that what the OP is feeling is his age (1.5 years out of 50 myself) and not so much the Q-Factor, unless his body is just so accustomed to the narrower Q-Factor for so long. What needs to be taken into account also is knee "orientation"?, i.e. when standing with your knees together, are your ankles also or are your feet apart (knock kneed)?

I think most people are slightly knock kneed and as such the wider Q-Factor helps with this, I know I am slightly and with XT M760 cranks, my knees actually overlap the TT at top of stroke when really cranking, has me thinking that going to an 83mm BB shell for a future PLUS build wouldn't be detrimental to being able to put power down.

OP, one thought, have you ever tried to do a squat with your feet close together vs shoulder width apart? Not as much control or ability to output nearly the same power because of lack of stability, hence why riders rock their bikes back and forth when sprinting and trying to put down as much power as possible.

 

I'd say that what the OP is feeling is his age (1.5 years out of 50 myself)

That might well be true -- increasing age trumps just about everything. But it also has me examining lots of things to keep my speed up as much as possible.

OP, one thought, have you ever tried to do a squat with your feet close together vs shoulder width apart? Not as much control or ability to output nearly the same power because of lack of stability, hence why riders rock their bikes back and forth when sprinting and trying to put down as much power as possible.

I have a 180° reverse interpretation/experience with both of these thoughts. One legged press (use a machine for this) -- absolutely my leg goes directly below my pelvis, even more body center than my hip joint. The two footed squat isn't really a good comparator to cranking a bike -- we do that one leg at a time. And when it comes to sprinting and rocking the bike, that's done to put the pedal in the best position under the leg and my read of it is that the rock decreases the effective Q-factor -- the power stroke (down from 3 to 6 o'clock) has the top tube pushed away from the engaged leg and that has the foot and leg driving down to the bottom bracket and the center of the body. Go to YouTube and dial up some road sprints and play some of the head on shots of Sagan and company at 0.25x speed.

 

This might be an issue of "accuracy" versus "precision". The speedometer on my road bike reads 1% short reproducibly -- so it will read 9.9 miles when I've ridden 10. It's not super "accurate", but it is "precise". Despite its "inaccuracy" it's a good tool to tell if one ride is 1% longer than another. I don't know the literature for power meters and don't have one so I don't know if it's an issue of precision, accuracy or both. So your point may be valid.

 

On a leg press you have full back support and are pushing from that anchor. Leg presses really don't mimick natural biometrics/kinesiology at all and I personally wouldn't recommend anybody do them, especially if you have lower back issues.

I kinda skimmed and don't know if this has been mentioned but efficiency is but one factor of pedal width/stance. Stability is a big factor as well as is bike control. The further you move the q-factor out the more leverage you have at the pedal, within reason of coarse. Some dh specific pedals have a longer axle for this reason.

 

My take is that if your not in your natural gate you are pushing side to side on the frame and flexing the frame. All frames flex, even AL frames. So, if you push down at an angle with 200 pounds of force 20 pounds of that force may be pushing on the frame each pedal stroke. You may be able to generate more force to flex your crank and peak your power meter arm but you may not necessarily be generating more power to the wheels. I would be more interested in studying the impact of Q factor against watt meters on the crank and watt meters at the wheel. If my legs are generating 500 watts I want 500 watts at the wheel and not 450 watts at the wheel and 50 watts flexing the cranks and frame. Watt meters in the crank calculate watts based on how much the crank is flexing and moving. They literally flex, stretch, and move every pedal stroke no matter how nice they are.

 

When SRAM first released the XX double crankset I accidentally bought the 156mm Q factor model. I was really surprised how much I disliked the feel compared to my previous 168 cranks.I really struggled to get used to it. I think I’ve got fairly wide hips at 6ft with a 34” waist. Eventually I switched back to 168 cranks and immediately felt more stable and powerful. I wouldn’t go back for any minimal power gains.

 

I'm the opposite - larger Q-factor is more comfortable, causes less pain in my right side. Better feeling of control.