Firstly I am 72 yo and wider than average build and need 46 cm c-c bars, 110 kg, carrying lots of injuries (Rugby and bike crashes) and OA. Suffered lateral patella knee pain, no patella lateral cartilage. Added 20 mm extensions to each pedals and lateral patella pain subsided. Lateral patella pain is also helped by riding more often out of the saddle, which is more difficult due to dropped foot due to ankle surgery. Still occasionally manage 50 km in two hours .
Fatbikes saved me big time when they came out... I had always struggled with knee and foot issues no matter what bike I had. When I got my first fat bike the wide Q-factor totally solved my issues, now I run pedal extenders on all my other bikes.
Definitely a helpful video for those of us trying to diagnose knee pain; coming from a touring/MTB/flat pedal background and moving in to a new CX/road bike, I've found myself with a lot of inner knee pain on a single side. Trying to address this knee pain without breaking the bank, traveling to find a true bike fitter (vs the classic "fistfull of seat post, and fistfull of stem,") or putting in undue labor is a tricky. After moving my cleats inboard of the shoes and still finding pain, it sounds like I should look in to pedal extenders next. Thanks man!
I am fairly short at 5' 4" and walk slightly duck-footed. I recently bought a fat bike for the winter. I regularly ride road and a summer mountain bike. I can honestly say it's the first time I noticed q factor, with a 100mm bb shell it's quite significant. I initially had strange pains on my back, tops of my knees and ankles. I have ridden spd's for the past 10 years also. Oh a whim, I switched to flats and lowered the seat slightly, and the pain gradually disappeared. I feel great on the bike. I feel like I have greatly changed my pedaling style too, with much more emphasis on my calves. When I got back on my road bike, the saddle seemed way to high. Thanks for the videos, you earned a subscriber today!
I started riding a recumbent about 2.5 yrs ago which affords me the opportunity to watch my pedaling regardless of whether I want to or not :). When I wanted to go for a low chainring of 22 the only convenient option was a Shimano Mountain triple since I have a older square taper bb - this requires me to have a 180 mm Q-factor. I'm 5' 6" medium build and I said to myself "wow my legs are really wide apart" with no ability to stand out of the saddle. Also I noticed my knees were "popping out" at the top of the stroke. I lied down on my floor one evening and looked at my feet as they were spread to the stance of the pedals and set the cleats "heeled-in" and this fixed EVERYTHING! Even a teeny-tiny sensation in the back of one knee that I often wondered the cause -just completely disappeared.
I added pedal extenders because I am knocked kneed and I have wide feet. the extenders help me keep a pedal stroke that uses the inside of my foot rather than the outside. I also use flat pedals to keep my foot from rotating outwards.
My LBS fitter has done quite a few small tweaks with me the last couple of years. One that was pretty painful was I'd get inner quad pain on my right leg only on rides at higher intensities (usually while climbing). At first the shop put a couple spacers in my pedal and that helped a bit. Then when Shimano released the wider Ultegra pedals, I switched to those and put the spacers back in my right pedal (my right foot is very toe out and I walk on the inside due to what I can only assume was a very badly healed sprain as a kid). It really has helped relieve that pain. I will still sometimes feel that part of that quad heat up but it settles down after 10-20 minutes. My wife on the other hand switched to Speedplays and one of the big reason was the narrow spindles. LBS had a pair of short spindle Speedplay Zeros lying around so the owner loaned them to her to try and eventually gave them to her. She is short and petite build and would get knee and hip pain. She's had a lot of issues fitting herself to her bike and both her and I think next time we may look at using a full fitting with one of the fitter bikes to figure out what would be a good setup before buying our next bikes. She's 5'2" and on a 50cm Trek Silque SLX. She's down to a 60cm stem, narrower bars, and shorter cranks. Seems like before looking at something like an Emonda next time, she's going to want to see if the 47cm would've been a better fit and if there are other frames that may make her happier.
The step by step history was well done, thanks. It does make sense that ideal Q would be somewhat related to hip width/range of motion so unusual that there isn't much out there on it as an element of bike fit. Will be interesting to know what you find out from that study. Would it stand to reason that it may be more critical for shorter legged riders as any change in Q would result in greater change of lateral angle at the hip? I was a little worried that putting a MTB double on my do-it-all bike would cause discomfort over longer distances, but it has proved fine even over a hilly 200K. With the right insoles I got great knee tracking in my bike fit, and if anything it has made me realise that my fixed gear having much narrower Q is perhaps the reason for some of the issues I feel riding it for longer distances... especially as it requires more exaggerated out-of-the-saddle riding for steeper climbs.
Great topic - thanks for tackling it! I recently had an experience where I purchased a road disc frame with widely-spaced chainstays; I purchased Shimano pedals with +4mm axles to mitigate heel rub and immediately felt my perceived exertion skyrocket. My hips seemed to rest differently through the pedal stroke and I felt different on the same saddle with all contact points duplicated from my prior bike. I also came from a 1st-gen BB30/Hollowgram system, to BB86+ultegra 6800 road double. I have a sneaky suspicion this added an additional 5-6mm q alongside the pedal spindles but I never took a measurement. (I wish there was a dynamic spreadsheet somewhere that combined popular bottom brackets, cranks and pedals to give you an ultimate stance or q width.) I'm sure I would have adapted to this setup, especially since people jump between their mtbs and road bikes with varying q all the time. But it made me realize that (at least for me) a moderate change in q can be felt.
I prefer a narrower Q-factor coming from a road/touring background. When I built my monster cross bike some 8 yrs. ago, this was the first time with a wider frame and with the Hollowtech crank set and external bearings. As designed, that would set me up with about 177.5mm Q-factor. I narrowed the BB down to 170mm and that works much better (triple crank): ruclips.net/video/Gs2_jS0rpQI/видео.html For some time, I ran with the cranks slightly offset (left side wider by 2.5mm) and found I was getting some left knee pain after a ride. When I narrowed the crank and got the cranks symmetrical, that left knee pain vanished. So yes, it's well worth experimenting with Q-factor.
I recently got a Trek gravel bike and developed knee discomfort over time. It wasn’t until I saw this video that I realised the Q factor was 20mm narrower than the two road bikes I’ve ridden for years! I’ve ordered some pedal extenders to see if that will resolve the problem.
Appreciate the explanations! Thanks so much. So, I kinda think of Q-factor like _stance_ when I am doing squats. Too wide (with feet parallel) is hard on knees and hips...too narrow and its kinda like doing narrow grip press; strength isn't as good and harder to balance. So, I've gotta believe there *is* an optimum in there somewhere but I'd bet its a pretty flat curve pretty tolerant to tens of milimeters variation either direction.
i'm building a bike from scratch and actually discovering all those amazing parameters ! i have a BB68 BSA thread and i wonder if it is not more interesting to stay on a square axle instead of a hollowtech , meaning you can choose from 103 to 118 with the square so that it s easier to tune your chainline and q-factor ? any chance to have tuning width option with a hollowtech ?
Surely the "ideal" Q factor is an anthropometric function based on the median of the hip joint, letting. The foot move perfectly inline with the hip Pivot point, no? I know this is not necessarily how most of us walk, but it is a mechanical option on a bicycle. I just had a wee hunt, and anthropometric hip joint dimensions are not easy to find. Incidentally, Issi (via QBP, USA) has 3 spindle lengths for some of their pedals, both 2 and 3 bolt cleat.
Another excellent video, thanks. I've had anterior knee pain for the past two months brought on by riding and think it might be linked to Q factor. I'm fine off the bike including running and hiking with a pack, but riding can make it worse, and I've gone from 600 miles a month to about 100 (commuting only)! A few months ago I got a bike fit on my race bike, rode it for two weeks no problem at all, then started getting the knee pain. So I put it down to that, but the only differences made were very small adjustments to my cleats, wedges to correct valgus foot position, and putting my seat up a bit. I think the seat actually went too high so I've put it down a bit, but I don't think the bike fit is the main culprit, and instead it might be my commuting bike which I fiddled with at a very similar time (a mistake in hindsight). It changed from a 68 mm square taper bb to a Hollowtech II, and my stance width on that bike is now a bit wider, and I noticed my knees tracking inside my feet, which can't be good. This is exacerbated by me commuting in SPDs which offer little way to move the cleat across, while my road shoes on my race bike are set with the cleats (Look Keo) as far to the outside of the shoe as possible resulting in a quite narrow stance. If I measure the distance between the toe of each shoe when clipped into the pedals it's about 226 mm on the race bike, about 258 mm on the Boardman, which sounds like a huge difference. Could this be a factor in the knee pain do you think? Sorry for the essay!
I have ridden a road bike for about 48 years 250 to 300 miles a week + MTB once a month.Got V poorly with the big C had a long hospital stay lost all muscle .so have been rideing a MTB with a triple c set for about 14 months to build my muscles back up , unfortunately with q factor being larger I have a really bad problem with hips now , started to get it walking as well, So gone back to road bike after 12 weeks the hip pain is getting better . can't do 100miles yet but hopefully i will get there.
The industry doesn't care about Q-factor what matter is chainline for their product to works. Great thing we have knee savers and square tappered crankset.
The “hanging” stance test is very interesting. Hang from a chin up bar, let your feet dangle to its natural stance. Come down to the ground, and measure the distance between your feet.
I imagine, a fairly efficient way to measure one's Q-factor - would be to have him / her walk (after dipping their feet or shoes in some sort of a marking matter), draw straight lines between footprints for each foot - then measure the distance between the lines in question.
Running and walking works differently as you pretty much just have your legs to center and stabilize you. This means you're going to place your feet closer to the midline of your body in order to not be falling off to the side or feeling unsteady. Now when you can rest your buttocks on a seat then you can worry about hip alignment and the most direct path to the pedal/most efficient pattern for power transfer - and of course that matches up with your anatomy. Also arch support isn't a huge thing in running and walking(nor is it necessarily necessary)
Morning & just watched this intuitive video . I am a father of fairly new Bmx’r & recently have gotten into the debate on these young kids & Q factor . Some fathers r dead set on narrowing the track width of the bikes which is great as they’re involved . My issue is some are so hellbent on making the setup ultra narrow meaning that where a 103-105mm bb would sit they’ll have the crank arms shaved to narrow down the track width beyond the normal track width . This all due to a few people claimed coaches or trainers input . My question is what is they adverse affects of having a track width that’s to narrow do to a riders performance ?? If you can envision a setup with barely 1-2mm spacing between the inner crank arm & chainstays .
I've got both extremes and the middle covered. Track bike, vintage steel road, and mountain cum touring bike with overly wide triple setup. I cope well with all but like the small and medium Q better than extra wide triple. Much easier to add Q with spacers than to lose. Refuse to use modern bb standards. I get it but most can't afford their problems.
There's another aspect to thinking about Q-factor in regard to bicycle design. The wider the Q the more the bike will tend to rock from side to side while pedaling, and the rider will need to expend more energy (in balance and upper body control) to keep the bike traveling in a straight line. Here we have a situation where biomechanics, mechanical engineering, and physics are in conflict, and we need to think of finding the optimum compromise, not the perfect solution.
One hugely important dimension for a pedal system is what is the stroke radius or the distance between the center of the crank shaft to the center of the pedal spindle or swivel point. Why is this ignored by manufactures' specs?
Another good video as usual. Q-factor is an interesting one. I'd never heard of the term but it's something I thought about often ... In squatting people are generally told to start with feet a little wider than shoulder width apart, and toes pointing out a bit. I, personally, like to have my feet a touch wider than most, with my toes pointing out more than most because I have very poor hip flexion with my legs narrow (down to the shape of the hip sockets I suppose - I feel real impingement in the hips if I squat with my legs pointing straight forward). I had always wondered, if this is the stance I am most happy to squat 200lbs in, why isn't it the stance I should be cycling. Now I know it would be ridiculous to be swinging my legs around that wide and that pointed, and I assume the rear half of the stroke is the limiting factor. However, after thinking this I made a little change to my cleat positioning to give me a wider effective stance and point my toes out slightly more and the slightly niggling knee discomfort (rather than pain, just awkward feeling) seems to have subsided a little. I assume, for those like me, a wider Q factor can also allow more comfortable hip flexion, allowing the pelvis to rest more tilted forward (or at least neutrally) possibly alleviating a whole load of problems with lower back pain. Does that sound sensible, or have I missed something?
Chris Holmes You are spot on. You're interpretation of what happens at the hips and pelvis when we match our q-factor to our mechanics is pretty much perfect
Great video and channel. After changing from being a road rider to a mtb rider the geometry on a 29r XC bike and q-factor it´s very similar to my knees. When you think on one step beyond and getting an enduro bike with widder BB and steep seat angle, that´s when things start to change. No offset posts, angles far more steep than 73º and wider Q-factors worth an special mention. ¿How we set ourserlves on an FS enduro mtb? Sorry for my english!! and again congratulations for these excelent videos
great explanation on Q factor. thank you. my question is it better to go with frame makers specs for frame design & performance or is it more preference related to a particular riding style/terrain? does boost have anything to do with Q? thanks again.
Interesting how q factor should be something individual, which would suggest that all cranks and bottom brackets should be standardized to allow for further tweaking per individual needs, but instead it's kind of pushed on to you by industry standard per bike category (road, xc etc). Also there are different standards between different pedals. For example shimano spd have 55mm crank to middle of the pedal, while spd-sl have 52mm crank to middle of the pedal, all contributing to even larger difference in q factor between road and mountain bikes. From my experience, I need a little wider q factor on a road bike due to my flat feet. My left foot is not as flat and I can ride different q factors, while my right one needs more space because I toe out when walking (and pedaling) and if the q factor is too narrow I will feel some pressure in the knee.
How do you measure the Q factor from one bike to another. I am setting up a new bike and I’m trying to get my q factors as close as possible. My older bike has the 386 bb I think you mentioned with the internal cups. I have a Shimano 24 crank on that. My new bike has a bb30 and I’m using a crank with a 30 mm spindle. Both cranks are the SRM Origin. The 30 mm requires spacers but the 24 mm doesn’t. Thanks
Hi John, I am riding a triple crankset FC-6603 by Shimano. My right outer crankarm is 4mm more away from the frame center than the left one. Did you ever stumbled over this asymmetric q-factor with Shimano triple cranksets? Thanks.
I had a case like this when a BB cartridge collapsed during a longer tour and I had it replaced by a first available workshop with the one of different specs. (I believe it was 68/114 instead of 68/110). The shop owner warned me, that they did not have a proper one. But I went for it, it was still better than riding with a creaking crank!! I had it replaced with a proper specs pretty soon, so I can't say what would be a consequence of prolonged use of it.
I think the shimano hollowtech 2 cranks push the right out further. I have a 6703 and it has a 6.5 mm spacer on the right and I think a 4 mm on the left. I put a 5 on the right and added a 2.5 on the left.
i'v measured the distance from Downtube to Pedal on my bike, the right one always be furthr away like 2mm or moreso i move my right cleat out 2mm to make both of my feet in d same distance, i also feel that my right leg is shorther (i cant see it myself) so far it's feels just fine
Good to know that i'm not the only one who is concern about that! I have an old road bike from the 90s with a "Q-factor" about 135 mm exterior to exterior crank arm (165 mm crank arm). Cadence feels smooth, knee/foot align and no pain. I also have a recent sporty road bike with a "Q-factor" about 160 mm (triple chainring crankset, 172.5 mm crank arm). I did a "bike fit" in a good shop, but I suffer of knee pain on that bike (with long rides). I feel like I pedal with my knees inside and my feet outside. Trying to be more comfortable, I adjusted my pedal cleats to have my toes a bit more outside. Incomfort is reduce, but it's still there... Also, i feel not efficient when pedalling with my knees a bit more outside. Do you think this few millimeters of width could be the problem ? I'm 178 cm tall, 84 cm leg lenght. I'm thinking of buying a race road bike, 140s mm "Q-factor", 170 mm crank arm.
Miguel Belanger It could be part of the cause, although trying to discern injuries issues between two bikes can be really challenging because there are often so many small differences. An easy and cheap way to investigate would be to move your cleats as far outboard on your shoes as possible. This will essentially move your feet slightly closer together and decrease the q-factor at least a little. Most cleats allow this type of adjustment. When dealing with cleats, as you look at the bottom of the cycling shoe you need to think in opposites -- if you want the feet to move further apart from one another, you need to move the cleats toward the inside of the shoe - want the feet to move closer together (decreasing stance) then you have to move the cleats out to the side. Then when you can ride the bike with the 160 mm q-factor and see if any of the symptoms change -- they're unlikely to go away completely but you might be able to discern either small improvements or no improvements over the next few rides.
Thanks for your response, very apreciated! Indeed, Iast week i just moved my cleats as far as it could to get my feet closer like you said (I have SPD mtb pedals on that bike). However, it only moved from 1 or 2 mm, so i can't tell a significant change. But as you said, i will try to do this with my Look road pedals, maybe the cleats will move further and would get my feet closer.
If your position on the 90's road bike is comfortable, transfer the saddle setback and height measurements (relative to the bottom bracket) exactly to the new road bike. Next lower the saddle exactly 7.5mm to account for the 7.5mm longer crank arms of the new bike (old ones you say are 165, new ones 172.5) and then further adjust the saddle height down in 2mm increments until the pedaling motion feels like riding the older bike (probably a further 4-6mm). Lowering the saddle height in 2mm increments after the initial 7.5mm is to account for the increased stance width. Wider stance on the bike effectively means you have a higher saddle height relative to the older road bike. Messing with your cleat position and bringing your feet closer to the crank arm is just another way to effectively lower your saddle height... but then you lose the clearance between crank arm and shoe to float your feet out if that is what they want (toeing out is a different problem relating to weak feet and ankles but is a much longer process to fix if you were to go that route). So in total, your new road bike should have the same saddle setback but will be roughly 11.5 to 13.5mm lower than your older road bike position. The reach and drop should be adjusted for with stem length and angle and/or handlebar reach/drop. You do not adjust saddle position to try and solve reach. Any fitter that does this should not be doing bike fits (think whether your new bike fit included this..)
Thanks for trying to help my case! Unfortunetely, i already did this kind of adjusments... I think a 7.5 mm longer crank and a Q-factor 25 mm closer could be significant in my problem. Because as you said, with the same saddle height (same extended leg at the bottom of the pedal stroke), at the top of the pedal stroke, my knee goes at least 15 mm higher and my feet goes 12-13 mm widder. It's not that much... but it's maybe just enough to cause some problems during the longer rides.
In my experience, Q-factor (or more specifically stance width taking into account pedal spindle and cleat placement) can be accounted for with saddle height and making sure my cleat placement allows adequate toe out for my pedaling style which allows my knees to track in line. I currently have flat and weak feet, specifically big toes which is a contributor to needing toe out as I tend to push through the outside toes instead of the balls of my feet and big toe. My walking and running gait also suffer from this as will most people with flat and weak feet. I am working to fix this and am noticing a pretty big difference in my gait and toe off as well as utilizing my glutes/hamstrings to stand and walk. Increasing my ankle ROM with calf stretching and strengthening also allows my feet to remain more straight as I drop my heel to push through the pedal stroke. In the same way people turn out their feet and widen their stance to gain hip and ankle ROM when squatting, the same things happen to a lesser extent on the bike. But back to the Q-factor, I have two road bikes and the stance width differs by about 10mm between them due to me currently needing to use the Shimano +4mm pedal spindles on one bike due to the crank arms being very straight vs the other bike. My shoes will rub on the crank arms of the straight crankset without the longer spindles and I don't want to change cleat position as it will then be wrong for the other bike with standard pedal spindles and crankarms that angles out slightly. So, to account for this slightly larger stance width on the second bike due to the longer pedal spindles I simply have to lower the saddle by roughly 2-3 mm (everything else being the same with saddle fore/aft position I can feel when the saddle is at the correct height when riding) which allows for the same amount of heel drop between the positions.
I've never paid attention to q-factor until now. That is because im planning to swap out the drivetrain of my new boost bike to Sram Eagle. Therefore, offsets on chainrings matter, crankarms matter, q-factor matters, bb matters (lets not get into bbs..im so confused).... I just want to get the correct chainline for this boost frame. Anyway, i do also have a Trek Farley fatbike...i bought it as a complete bike..so i never paid attention to the q-factor..it climbs welll, decends well, therefore my takes on q-factor as far as ridings goes..i could careless... I just want it to fit within specs, and the crankarms dont hit the chainstay...that's it.
Hi there, Great video! I have a question I can't seem to find a good answer to. I'm small (165cm) but a bit bow legged and have quite a lot of knee problems when riding a roadbike. While I'm Dutch I have a lot of experience biking, I never had these knee problems when I ride my normal city bike. What I do notice is that I naturally put my feet a lot wider normally than my roadbike allows me to do. Do you think being bow legged asks for a wider q-factor?
Robert Mikkelsen Good question. And a very tough one to answer. There are a number of reasons to want a wider stance on the bike, but it gets tricky because we can benefit from this on both sides or sometimes just on one side. I wish I had a simple rule for you but unfortunately I don't. Sometimes bigger riders benefit from a wider q-factor simply because their hips are wider and they have a wider natural stance. Also if a rider isn't sitting square on the saddle they might have better mechanics with a wider q-factor on one side. Generally it's best to test them out (through a bike fit or if you find a shop that might help you demo a pair) before jumping into them.
hi, just got a fatbike, problem with the left knee after 20 min. my knee got a litle wide, and was a litle painfull to walk. the doctor give me prednison 20 mg for a week ( with no biking). I have a litle meniscus injurie 2, 5 years ago) probabli was that and i didnt ajusr the setle. becarfull .
swakk19 No at all. Cross training between different bikes can be a really effective way to improve overall riding ability and fitness. Just means that we have to be a little more careful with our mechanics and pay attention to any possible niggles that creep in when we switch from one to the next. Thanks for watching!
This piece assumes that external cups are "standard" but this is not so. Check out eddy Merckx's bike with a 68mm bottom bracket shell and an INTERNAL bottom bracket bearing. This narrow set up was the norm from c1880 to c1990. a narrow Q factor didn't slow Eddy down too much!
I'm broad across the beams/shoulders and hips and feel more comfortable on a road bike with a wide Q-factor. If I try run a narrower q-factor, I tend to suffer from excruciating iliotibial band friction syndrome.. I use speedplay zero pedals with their ridiculously expensive and overpriced 65mm or half inch longer than standard stainless steel spindles..
Q factor has to do with the anatomy of your hip and how that translates to your knee and foot/ankle and vice versa and very little with how big your bum or belly is aside from belly to thigh clearance.
Firstly I am 72 yo and wider than average build and need 46 cm c-c bars, 110 kg, carrying lots of injuries (Rugby and bike crashes) and OA. Suffered lateral patella knee pain, no patella lateral cartilage. Added 20 mm extensions to each pedals and lateral patella pain subsided. Lateral patella pain is also helped by riding more often out of the saddle, which is more difficult due to dropped foot due to ankle surgery. Still occasionally manage 50 km in two hours .
Fatbikes saved me big time when they came out... I had always struggled with knee and foot issues no matter what bike I had. When I got my first fat bike the wide Q-factor totally solved my issues, now I run pedal extenders on all my other bikes.
Definitely a helpful video for those of us trying to diagnose knee pain; coming from a touring/MTB/flat pedal background and moving in to a new CX/road bike, I've found myself with a lot of inner knee pain on a single side. Trying to address this knee pain without breaking the bank, traveling to find a true bike fitter (vs the classic "fistfull of seat post, and fistfull of stem,") or putting in undue labor is a tricky. After moving my cleats inboard of the shoes and still finding pain, it sounds like I should look in to pedal extenders next.
Thanks man!
I am fairly short at 5' 4" and walk slightly duck-footed. I recently bought a fat bike for the winter. I regularly ride road and a summer mountain bike. I can honestly say it's the first time I noticed q factor, with a 100mm bb shell it's quite significant. I initially had strange pains on my back, tops of my knees and ankles. I have ridden spd's for the past 10 years also. Oh a whim, I switched to flats and lowered the seat slightly, and the pain gradually disappeared. I feel great on the bike. I feel like I have greatly changed my pedaling style too, with much more emphasis on my calves. When I got back on my road bike, the saddle seemed way to high. Thanks for the videos, you earned a subscriber today!
Finally, I understand the variables to the "Q" and how that could affect my cycling over the long ride and performance.
I started riding a recumbent about 2.5 yrs ago which affords me the opportunity to watch my pedaling regardless of whether I want to or not :). When I wanted to go for a low chainring of 22 the only convenient option was a Shimano Mountain triple since I have a older square taper bb - this requires me to have a 180 mm Q-factor. I'm 5' 6" medium build and I said to myself "wow my legs are really wide apart" with no ability to stand out of the saddle. Also I noticed my knees were "popping out" at the top of the stroke. I lied down on my floor one evening and looked at my feet as they were spread to the stance of the pedals and set the cleats "heeled-in" and this fixed EVERYTHING! Even a teeny-tiny sensation in the back of one knee that I often wondered the cause -just completely disappeared.
I added pedal extenders because I am knocked kneed and I have wide feet. the extenders help me keep a pedal stroke that uses the inside of my foot rather than the outside. I also use flat pedals to keep my foot from rotating outwards.
My LBS fitter has done quite a few small tweaks with me the last couple of years. One that was pretty painful was I'd get inner quad pain on my right leg only on rides at higher intensities (usually while climbing). At first the shop put a couple spacers in my pedal and that helped a bit. Then when Shimano released the wider Ultegra pedals, I switched to those and put the spacers back in my right pedal (my right foot is very toe out and I walk on the inside due to what I can only assume was a very badly healed sprain as a kid). It really has helped relieve that pain. I will still sometimes feel that part of that quad heat up but it settles down after 10-20 minutes.
My wife on the other hand switched to Speedplays and one of the big reason was the narrow spindles. LBS had a pair of short spindle Speedplay Zeros lying around so the owner loaned them to her to try and eventually gave them to her. She is short and petite build and would get knee and hip pain. She's had a lot of issues fitting herself to her bike and both her and I think next time we may look at using a full fitting with one of the fitter bikes to figure out what would be a good setup before buying our next bikes. She's 5'2" and on a 50cm Trek Silque SLX. She's down to a 60cm stem, narrower bars, and shorter cranks. Seems like before looking at something like an Emonda next time, she's going to want to see if the 47cm would've been a better fit and if there are other frames that may make her happier.
I am a wide build 46 cm c-c bars. Lateral patella pain, 20 mm pedal spindle extensions no more patella pain.
The step by step history was well done, thanks. It does make sense that ideal Q would be somewhat related to hip width/range of motion so unusual that there isn't much out there on it as an element of bike fit. Will be interesting to know what you find out from that study. Would it stand to reason that it may be more critical for shorter legged riders as any change in Q would result in greater change of lateral angle at the hip?
I was a little worried that putting a MTB double on my do-it-all bike would cause discomfort over longer distances, but it has proved fine even over a hilly 200K. With the right insoles I got great knee tracking in my bike fit, and if anything it has made me realise that my fixed gear having much narrower Q is perhaps the reason for some of the issues I feel riding it for longer distances... especially as it requires more exaggerated out-of-the-saddle riding for steeper climbs.
Thanks for the video. Q-factor is extremely important for my Brompton folding bike when I upgrade my crankset.
Great topic - thanks for tackling it! I recently had an experience where I purchased a road disc frame with widely-spaced chainstays; I purchased Shimano pedals with +4mm axles to mitigate heel rub and immediately felt my perceived exertion skyrocket. My hips seemed to rest differently through the pedal stroke and I felt different on the same saddle with all contact points duplicated from my prior bike.
I also came from a 1st-gen BB30/Hollowgram system, to BB86+ultegra 6800 road double. I have a sneaky suspicion this added an additional 5-6mm q alongside the pedal spindles but I never took a measurement. (I wish there was a dynamic spreadsheet somewhere that combined popular bottom brackets, cranks and pedals to give you an ultimate stance or q width.)
I'm sure I would have adapted to this setup, especially since people jump between their mtbs and road bikes with varying q all the time. But it made me realize that (at least for me) a moderate change in q can be felt.
Erik Leung you're not alone in your sensitivity to q-factor. Thanks for watching!
I prefer a narrower Q-factor coming from a road/touring background. When I built my monster cross bike some 8 yrs. ago, this was the first time with a wider frame and with the Hollowtech crank set and external bearings. As designed, that would set me up with about 177.5mm Q-factor. I narrowed the BB down to 170mm and that works much better (triple crank):
ruclips.net/video/Gs2_jS0rpQI/видео.html
For some time, I ran with the cranks slightly offset (left side wider by 2.5mm) and found I was getting some left knee pain after a ride. When I narrowed the crank and got the cranks symmetrical, that left knee pain vanished. So yes, it's well worth experimenting with Q-factor.
I recently got a Trek gravel bike and developed knee discomfort over time. It wasn’t until I saw this video that I realised the Q factor was 20mm narrower than the two road bikes I’ve ridden for years! I’ve ordered some pedal extenders to see if that will resolve the problem.
Appreciate the explanations! Thanks so much. So, I kinda think of Q-factor like _stance_ when I am doing squats. Too wide (with feet parallel) is hard on knees and hips...too narrow and its kinda like doing narrow grip press; strength isn't as good and harder to balance. So, I've gotta believe there *is* an optimum in there somewhere but I'd bet its a pretty flat curve pretty tolerant to tens of milimeters variation either direction.
+Mark Miller I think I agree with all of that...
i'm building a bike from scratch and actually discovering all those amazing parameters ! i have a BB68 BSA thread and i wonder if it is not more interesting to stay on a square axle instead of a hollowtech , meaning you can choose from 103 to 118 with the square so that it s easier to tune your chainline and q-factor ? any chance to have tuning width option with a hollowtech ?
Surely the "ideal" Q factor is an anthropometric function based on the median of the hip joint, letting. The foot move perfectly inline with the hip Pivot point, no? I know this is not necessarily how most of us walk, but it is a mechanical option on a bicycle.
I just had a wee hunt, and anthropometric hip joint dimensions are not easy to find.
Incidentally, Issi (via QBP, USA) has 3 spindle lengths for some of their pedals, both 2 and 3 bolt cleat.
I installed pedal extenders, I feel happy with them so far.
Another excellent video, thanks.
I've had anterior knee pain for the past two months brought on by riding and think it might be linked to Q factor. I'm fine off the bike including running and hiking with a pack, but riding can make it worse, and I've gone from 600 miles a month to about 100 (commuting only)! A few months ago I got a bike fit on my race bike, rode it for two weeks no problem at all, then started getting the knee pain. So I put it down to that, but the only differences made were very small adjustments to my cleats, wedges to correct valgus foot position, and putting my seat up a bit. I think the seat actually went too high so I've put it down a bit, but I don't think the bike fit is the main culprit, and instead it might be my commuting bike which I fiddled with at a very similar time (a mistake in hindsight). It changed from a 68 mm square taper bb to a Hollowtech II, and my stance width on that bike is now a bit wider, and I noticed my knees tracking inside my feet, which can't be good. This is exacerbated by me commuting in SPDs which offer little way to move the cleat across, while my road shoes on my race bike are set with the cleats (Look Keo) as far to the outside of the shoe as possible resulting in a quite narrow stance. If I measure the distance between the toe of each shoe when clipped into the pedals it's about 226 mm on the race bike, about 258 mm on the Boardman, which sounds like a huge difference. Could this be a factor in the knee pain do you think? Sorry for the essay!
I have ridden a road bike for about 48 years 250 to 300 miles a week + MTB once a month.Got V poorly with the big C had a long hospital stay lost all muscle .so have been rideing a MTB with a triple c set for about 14 months to build my muscles back up , unfortunately with q factor being larger I have a really bad problem with hips now , started to get it walking as well, So gone back to road bike after 12 weeks the hip pain is getting better . can't do 100miles yet but hopefully i will get there.
Is there a bike fit expert with anywhere near your expertise around Houston you could recommend? Thanks a million, Scott
Nothing but a track bike below 140 is good for me. When i ride different bike it's always a compromise but i tried to get it low is possible
The industry doesn't care about Q-factor what matter is chainline for their product to works.
Great thing we have knee savers and square tappered crankset.
Excelente, me aclaró algunas dudas respecto a la incidencia del ancho de bielas en la potencia de pedaleo.
The “hanging” stance test is very interesting. Hang from a chin up bar, let your feet dangle to its natural stance. Come down to the ground, and measure the distance between your feet.
I imagine, a fairly efficient way to measure one's Q-factor - would be to have him / her walk (after dipping their feet or shoes in some sort of a marking matter), draw straight lines between footprints for each foot - then measure the distance between the lines in question.
Running and walking works differently as you pretty much just have your legs to center and stabilize you. This means you're going to place your feet closer to the midline of your body in order to not be falling off to the side or feeling unsteady. Now when you can rest your buttocks on a seat then you can worry about hip alignment and the most direct path to the pedal/most efficient pattern for power transfer - and of course that matches up with your anatomy. Also arch support isn't a huge thing in running and walking(nor is it necessarily necessary)
Morning & just watched this intuitive video . I am a father of fairly new Bmx’r & recently have gotten into the debate on these young kids & Q factor . Some fathers r dead set on narrowing the track width of the bikes which is great as they’re involved . My issue is some are so hellbent on making the setup ultra narrow meaning that where a 103-105mm bb would sit they’ll have the crank arms shaved to narrow down the track width beyond the normal track width . This all due to a few people claimed coaches or trainers input .
My question is what is they adverse affects of having a track width that’s to narrow do to a riders performance ?? If you can envision a setup with barely 1-2mm spacing between the inner crank arm & chainstays .
I've got both extremes and the middle covered. Track bike, vintage steel road, and mountain cum touring bike with overly wide triple setup. I cope well with all but like the small and medium Q better than extra wide triple. Much easier to add Q with spacers than to lose. Refuse to use modern bb standards. I get it but most can't afford their problems.
another brilliant video John.
There's another aspect to thinking about Q-factor in regard to bicycle design. The wider the Q the more the bike will tend to rock from side to side while pedaling, and the rider will need to expend more energy (in balance and upper body control) to keep the bike traveling in a straight line. Here we have a situation where biomechanics, mechanical engineering, and physics are in conflict, and we need to think of finding the optimum compromise, not the perfect solution.
Yes of course rocking motion and wear and tear on those damned press fit bb in a carbon frame!
One hugely important dimension for a pedal system is what is the stroke radius or the distance between the center of the crank shaft to the center of the pedal spindle or swivel point. Why is this ignored by manufactures' specs?
Another good video as usual.
Q-factor is an interesting one. I'd never heard of the term but it's something I thought about often ...
In squatting people are generally told to start with feet a little wider than shoulder width apart, and toes pointing out a bit. I, personally, like to have my feet a touch wider than most, with my toes pointing out more than most because I have very poor hip flexion with my legs narrow (down to the shape of the hip sockets I suppose - I feel real impingement in the hips if I squat with my legs pointing straight forward).
I had always wondered, if this is the stance I am most happy to squat 200lbs in, why isn't it the stance I should be cycling.
Now I know it would be ridiculous to be swinging my legs around that wide and that pointed, and I assume the rear half of the stroke is the limiting factor. However, after thinking this I made a little change to my cleat positioning to give me a wider effective stance and point my toes out slightly more and the slightly niggling knee discomfort (rather than pain, just awkward feeling) seems to have subsided a little.
I assume, for those like me, a wider Q factor can also allow more comfortable hip flexion, allowing the pelvis to rest more tilted forward (or at least neutrally) possibly alleviating a whole load of problems with lower back pain.
Does that sound sensible, or have I missed something?
Chris Holmes You are spot on. You're interpretation of what happens at the hips and pelvis when we match our q-factor to our mechanics is pretty much perfect
Great video and channel. After changing from being a road rider to a mtb rider the geometry on a 29r XC bike and q-factor it´s very similar to my knees. When you think on one step beyond and getting an enduro bike with widder BB and steep seat angle, that´s when things start to change. No offset posts, angles far more steep than 73º and wider Q-factors worth an special mention. ¿How we set ourserlves on an FS enduro mtb? Sorry for my english!! and again congratulations for these excelent videos
great explanation on Q factor. thank you. my question is it better to go with frame makers specs for frame design & performance or is it more preference related to a particular riding style/terrain? does boost have anything to do with Q? thanks again.
Excellent vid, great information. Thanks. Did you get to the bottom of how to measure ideal q factor?
Interesting how q factor should be something individual, which would suggest that all cranks and bottom brackets should be standardized to allow for further tweaking per individual needs, but instead it's kind of pushed on to you by industry standard per bike category (road, xc etc). Also there are different standards between different pedals. For example shimano spd have 55mm crank to middle of the pedal, while spd-sl have 52mm crank to middle of the pedal, all contributing to even larger difference in q factor between road and mountain bikes.
From my experience, I need a little wider q factor on a road bike due to my flat feet. My left foot is not as flat and I can ride different q factors, while my right one needs more space because I toe out when walking (and pedaling) and if the q factor is too narrow I will feel some pressure in the knee.
How do you measure the Q factor from one bike to another. I am setting up a new bike and I’m trying to get my q factors as close as possible. My older bike has the 386 bb I think you mentioned with the internal cups. I have a Shimano 24 crank on that. My new bike has a bb30 and I’m using a crank with a 30 mm spindle. Both cranks are the SRM Origin. The 30 mm requires spacers but the 24 mm doesn’t. Thanks
Hi John, I am riding a triple crankset FC-6603 by Shimano. My right outer crankarm is 4mm more away from the frame center than the left one. Did you ever stumbled over this asymmetric q-factor with Shimano triple cranksets? Thanks.
I had a case like this when a BB cartridge collapsed during a longer tour and I had it replaced by a first available workshop with the one of different specs. (I believe it was 68/114 instead of 68/110). The shop owner warned me, that they did not have a proper one. But I went for it, it was still better than riding with a creaking crank!! I had it replaced with a proper specs pretty soon, so I can't say what would be a consequence of prolonged use of it.
I think the shimano hollowtech 2 cranks push the right out further. I have a 6703 and it has a 6.5 mm spacer on the right and I think a 4 mm on the left. I put a 5 on the right and added a 2.5 on the left.
Do you have a link to the research article you reference?
i'v measured the distance from Downtube to Pedal on my bike, the right one always be furthr away like 2mm or moreso i move my right cleat out 2mm to make both of my feet in d same distance, i also feel that my right leg is shorther (i cant see it myself) so far it's feels just fine
Good to know that i'm not the only one who is concern about that! I have an old road bike from the 90s with a "Q-factor" about 135 mm exterior to exterior crank arm (165 mm crank arm). Cadence feels smooth, knee/foot align and no pain.
I also have a recent sporty road bike with a "Q-factor" about 160 mm (triple chainring crankset, 172.5 mm crank arm). I did a "bike fit" in a good shop, but I suffer of knee pain on that bike (with long rides). I feel like I pedal with my knees inside and my feet outside. Trying to be more comfortable, I adjusted my pedal cleats to have my toes a bit more outside. Incomfort is reduce, but it's still there... Also, i feel not efficient when pedalling with my knees a bit more outside.
Do you think this few millimeters of width could be the problem ? I'm 178 cm tall, 84 cm leg lenght. I'm thinking of buying a race road bike, 140s mm "Q-factor", 170 mm crank arm.
Miguel Belanger It could be part of the cause, although trying to discern injuries issues between two bikes can be really challenging because there are often so many small differences. An easy and cheap way to investigate would be to move your cleats as far outboard on your shoes as possible. This will essentially move your feet slightly closer together and decrease the q-factor at least a little. Most cleats allow this type of adjustment. When dealing with cleats, as you look at the bottom of the cycling shoe you need to think in opposites -- if you want the feet to move further apart from one another, you need to move the cleats toward the inside of the shoe - want the feet to move closer together (decreasing stance) then you have to move the cleats out to the side.
Then when you can ride the bike with the 160 mm q-factor and see if any of the symptoms change -- they're unlikely to go away completely but you might be able to discern either small improvements or no improvements over the next few rides.
Thanks for your response, very apreciated!
Indeed, Iast week i just moved my cleats as far as it could to get my feet closer like you said (I have SPD mtb pedals on that bike). However, it only moved from 1 or 2 mm, so i can't tell a significant change. But as you said, i will try to do this with my Look road pedals, maybe the cleats will move further and would get my feet closer.
If your position on the 90's road bike is comfortable, transfer the saddle setback and height measurements (relative to the bottom bracket) exactly to the new road bike. Next lower the saddle exactly 7.5mm to account for the 7.5mm longer crank arms of the new bike (old ones you say are 165, new ones 172.5) and then further adjust the saddle height down in 2mm increments until the pedaling motion feels like riding the older bike (probably a further 4-6mm). Lowering the saddle height in 2mm increments after the initial 7.5mm is to account for the increased stance width.
Wider stance on the bike effectively means you have a higher saddle height relative to the older road bike. Messing with your cleat position and bringing your feet closer to the crank arm is just another way to effectively lower your saddle height... but then you lose the clearance between crank arm and shoe to float your feet out if that is what they want (toeing out is a different problem relating to weak feet and ankles but is a much longer process to fix if you were to go that route).
So in total, your new road bike should have the same saddle setback but will be roughly 11.5 to 13.5mm lower than your older road bike position.
The reach and drop should be adjusted for with stem length and angle and/or handlebar reach/drop. You do not adjust saddle position to try and solve reach. Any fitter that does this should not be doing bike fits (think whether your new bike fit included this..)
Thanks for trying to help my case! Unfortunetely, i already did this kind of adjusments...
I think a 7.5 mm longer crank and a Q-factor 25 mm closer could be significant in my problem. Because as you said, with the same saddle height (same extended leg at the bottom of the pedal stroke), at the top of the pedal stroke, my knee goes at least 15 mm higher and my feet goes 12-13 mm widder. It's not that much... but it's maybe just enough to cause some problems during the longer rides.
In my experience, Q-factor (or more specifically stance width taking into account pedal spindle and cleat placement) can be accounted for with saddle height and making sure my cleat placement allows adequate toe out for my pedaling style which allows my knees to track in line.
I currently have flat and weak feet, specifically big toes which is a contributor to needing toe out as I tend to push through the outside toes instead of the balls of my feet and big toe. My walking and running gait also suffer from this as will most people with flat and weak feet. I am working to fix this and am noticing a pretty big difference in my gait and toe off as well as utilizing my glutes/hamstrings to stand and walk. Increasing my ankle ROM with calf stretching and strengthening also allows my feet to remain more straight as I drop my heel to push through the pedal stroke. In the same way people turn out their feet and widen their stance to gain hip and ankle ROM when squatting, the same things happen to a lesser extent on the bike.
But back to the Q-factor, I have two road bikes and the stance width differs by about 10mm between them due to me currently needing to use the Shimano +4mm pedal spindles on one bike due to the crank arms being very straight vs the other bike. My shoes will rub on the crank arms of the straight crankset without the longer spindles and I don't want to change cleat position as it will then be wrong for the other bike with standard pedal spindles and crankarms that angles out slightly.
So, to account for this slightly larger stance width on the second bike due to the longer pedal spindles I simply have to lower the saddle by roughly 2-3 mm (everything else being the same with saddle fore/aft position I can feel when the saddle is at the correct height when riding) which allows for the same amount of heel drop between the positions.
I've never paid attention to q-factor until now. That is because im planning to swap out the drivetrain of my new boost bike to Sram Eagle. Therefore, offsets on chainrings matter, crankarms matter, q-factor matters, bb matters (lets not get into bbs..im so confused).... I just want to get the correct chainline for this boost frame. Anyway, i do also have a Trek Farley fatbike...i bought it as a complete bike..so i never paid attention to the q-factor..it climbs welll, decends well, therefore my takes on q-factor as far as ridings goes..i could careless... I just want it to fit within specs, and the crankarms dont hit the chainstay...that's it.
I have heard many complaints from users that the pedals extenders tend to break. Especially if you are a competitive cyclist. What you think?
Hi there,
Great video!
I have a question I can't seem to find a good answer to.
I'm small (165cm) but a bit bow legged and have quite a lot of knee problems when riding a roadbike.
While I'm Dutch I have a lot of experience biking, I never had these knee problems when I ride my normal city bike. What I do notice is that I naturally put my feet a lot wider normally than my roadbike allows me to do.
Do you think being bow legged asks for a wider q-factor?
How to know if you need wider pedals? I see shimano Has a New +4 mm version of the New Ultegra model.
Robert Mikkelsen Good question. And a very tough one to answer. There are a number of reasons to want a wider stance on the bike, but it gets tricky because we can benefit from this on both sides or sometimes just on one side.
I wish I had a simple rule for you but unfortunately I don't. Sometimes bigger riders benefit from a wider q-factor simply because their hips are wider and they have a wider natural stance. Also if a rider isn't sitting square on the saddle they might have better mechanics with a wider q-factor on one side.
Generally it's best to test them out (through a bike fit or if you find a shop that might help you demo a pair) before jumping into them.
Bike Fit Adviser I don't know if my hips are wide but my thighs are. Good advice, thanks :)
hi, just got a fatbike, problem with the left knee after 20 min. my knee got a litle wide, and was a litle painfull to walk. the doctor give me prednison 20 mg for a week ( with no biking). I have a litle meniscus injurie 2, 5 years ago) probabli was that and i didnt ajusr the setle. becarfull .
Cannondale FatCAAD has the lowest Q factor in Fatbikes
does that mean its pointless to train on a road bike if (to improve stamina) in preparation for an enduro mtb race?
swakk19 No at all. Cross training between different bikes can be a really effective way to improve overall riding ability and fitness. Just means that we have to be a little more careful with our mechanics and pay attention to any possible niggles that creep in when we switch from one to the next. Thanks for watching!
super thanks. between optimal crank length and q factor which one will translate more watts? all I know
is both will be good.
Let’s chase whoever coined it ‘Q Factor’ out of town.
This piece assumes that external cups are "standard" but this is not so. Check out eddy Merckx's bike with a 68mm bottom bracket shell and an INTERNAL bottom bracket bearing. This narrow set up was the norm from c1880 to c1990. a narrow Q factor didn't slow Eddy down too much!
I'm broad across the beams/shoulders and hips and feel more comfortable on a road bike with a wide Q-factor. If I try run a narrower q-factor, I tend to suffer from excruciating iliotibial band friction syndrome.. I use speedplay zero pedals with their ridiculously expensive and overpriced 65mm or half inch longer than standard stainless steel spindles..
I see you have become inactive. But thank you for the knowledge.
I wonder if some women would benefit from widened q-factors. Wider pelvises relative to men.
I also imagine, particularly thin people would sport an overweeningly narrow Q-Factor, while obese ones would, to the contrary, have a wide Q-Factor.
Q factor has to do with the anatomy of your hip and how that translates to your knee and foot/ankle and vice versa and very little with how big your bum or belly is aside from belly to thigh clearance.