The Most Overlooked Bike Fit Measurment - Q Factor Explained 

Loving the regular James clips update

I'm so glad this video has been done, I adjusted my Q factor 18 months ago after looking into why I had pain and numbness, and its helped me for the better, no more knee pain, numb feet, shin splints and seat numbness. Whether it's correct or not, I measured my natural stance, then measured my pedals middle to middle, and then extended my pedals by 16mm. Thanks to watching your bike fitters videos I have got my bike set up correctly, also I've gone from 175mm crank arms to 165mm.

Perhaps obvious to some but still worth noting: MTB cranksets are also way wider than their road (and gravel) counterparts, so if you're experiencing pain on your road bike but an MTB feels fine, that might be worth looking into. I got the SQlab +15mm MTB pedals on my gravel bike last summer and that seemed to mitigate a lot of the knee pain I was having, but my issue was long term so I had to work with a physio to get the leg moving the way it's supposed to before I could really tell.

Saw this tip in another video with James in it and since then i've massively changed my stance and made it wider. No more foot and knee pain!

May 2023 took the plunge and purchased the Asioma shi upgrade for my Ultegra pedals fully aware of the increase in Q factor. Absolutely transformed the comfort on my bike unexpectedly. amazing really !!😊

I added some cheap spacers to widen my Q factor about a year ago, I have had had a lot of problems with my feet especially on the knuckle of the small toe and very hard skin in that area where the pressure is on that spot all of the time. The increase in Q factor with these spacers has improved this no end and combined with moving the (SPD) cleats as far back as possible I no longer have knee issues either. (I hope I have not just jinxed myself)

I allways enjoy these Bike Fit Jamesdays.

About time! As a 1980/90's MTB rider I have always hated the narrow stance on road bikes it's why I run 16mm Axle spacers on my pedals! Historically a few Bike snobs have taken the piss out of my wider stance!

Was on the verge of giving up cycling about fifteen years ago, was plagued with debilitating knee pain and saddle issues.. Then I managed to find some 59 and 65 mm speedplay zero spindles... Honestly they have been a total game changer in terms of comfort on the bike..

Thank you so much for this! I've already tried pushing my cleats in but I'll definitely try the rest! I've been wanting to know more for ages!! 🥰

Top advice from James as always,love the 2mm pedal washer hack,great to experiment without breaking the bank,excellent.

Excellent information, thanks James! Will definitely give it a try, since I do have on occasion inner knee pain.

Listening to James on these videos got me thinking about stance a while ago and I fitted 16mm spacers because I was having problem with knee/leg pain......As an older rider I found I had almost no knee pain and actually felt stronger on the bike ...being able to accelerate better. Thanks James!

Great info James, excellent to hear a bikefitter talk sense on this subject!

During a pro bike fit I was prescribed a pedal extension on the left and a couple of washer on the right. Game changing for my riding, together with shoe inserts!

These videos on stance are really valuable. MTBs have always given me ITB problems, that go away after returning to road bikes. I suspected it was excessive stance, but now I know. I am a fair bit slimmer than "average size", of course :) Thank you!

I have done all 3 to make the rides comfortable: 172.5 to 160mm crank arms, wide shoes, wider q-factor with both DA +4mm & Assioma-Shi.

You're right, they forget about that, and I do too. Thanks for the video, James, you're the best

I am using Risk's titanium 16mm pedal extender and it worked well for many years till today with no issues. Great cost saving alternative. Could give that a try.

Why do you recommend to comment your questions below? You don’t answer any viewers questions.

Thank you for this video. I have learned a lot and all is done in entertaining manner. I found q-factor super important for little riders, as crank width combined with short leg gives quite noticable angles. You may notice that some childrens looks like duck, body is moving laterally. Usually kids do not need sport performance, but noticable efficiency drop may take out all joy from activity. Cheers.

Thanks to James quick tip last bike fit tuesdays. I stanced out my Shimano SPD SL cleats and now I have eliminated the rubbing of my thick thighs on my saddle anymore. It also eliminated the pressure on the outside of my feet.

I grabbed a pair of the wider Shimano SPD pedals from James previous video on crank rubbing. It’s fixed a couple of issues I had.

Sweet. Please add to Bike Fit Tuesdays playlist!

Super useful tips. Thanks guys 🙂

A huge issue for those of us who go from a road/gravel bike to a mountain bike and back. Measured the difference between my 2 bikes a couple of years ago and found it to be around 20mm. At the time QBP, a US bike parts distributor had a house brand of pedals called ISSI for which you get axle kits of different lengths. With the 10mm axle and their pedal, my stance between gravel and mountain bike is within 1mm. Sadly, the ISSI brand is no longer but the SQLab stuff looks great. Thank you, James, for shining a light on this as I suspect there are lots of folks who have knee/hip and other issues, try all sorts of things but never change this aspect of their fit and wonder why they still have pain. Great stuff as always!

This is a such a good point. I have cycled for years and have a 155 saddle fit, and I also have arthritis in the inside of my hips from too much rugby. The Qfactor on a mtb is far better for me that a road setup. I am actually really surprised that bike com9and marketing teams haven’t picked up on this topic more.

Recently had a bike fit and one of the main takeaways was I needed a wider Q factor. Ordered the Shimano Ultegra extra wide pedals and noticed an immediate improvement. I find it easier getting over the top of the pedal stroke now and less knee pain.

Yep, as a fitter I agree with pretty much everything here. More often than not I am widening rather than narrowing someone's stance. Always worth going to see someone to check this is right for you.

I have splayed feet, common among men, and use 20mm extenders with my cleats twisted as far as possible. This eliminated knee pain. But I still can't turn my heels out far enough to release road pedals so I use Shimano mtb pedals with multi-release cleats. They are a game-changer for riders with anxiety about clipless pedals.

At 6’5”, cheap 20mm pedal extenders solved my knee problems. Took a little getting used to when climbing out of the saddle, but back to back big rides no longer an issue for me.

I got some Shimano pedals with the longer q-factor a couple years ago and haven't had any of the knee or foot problems since. Granted, I also started working out and stretching the related muscles, but they seem to have helped solve the problem.

Loving Harry Max’s Nationals cameo!

I discovered this some time ago through experimentation I now run a 2mm shim on my pedals and in so doing my knee pains are all gone☝🏾and I feel more balanced on the bike as well

Should the stance spacing be equal ? Is there a natural offset? For instance my right (mechanical side) leg naturally tracks closer to the frame. I adjusted my left cleat to make it more equal.

I have Favero Assioma duo shi on my bike and could not be happier. Got them as oart of a bike fit where every single contact point on the bike was altered so hard to say what impact just the pedals had but I’m way more comfortable and it’s an excellent power meter too

I really love my SQlab SPD +15!!!! Just keep in mind heelrubbing on chainstay ;)

trying out clipless pedals (shimano SPD M530's, gotta start somewhere) for the first time after years of using flats on my gravel bike. i immediately felt uncomfortable with how close my feet were once i was clipped in. my shoes were so close to the crank. my knees and hips felt weird. i felt like i was pushing down with the outside of my foot rather than on the balls of my toes. my mechanic says they're made that way for aero purposes, but i don't need to be aero. i just go out every morning for a cup of coffee and a bucket of sweat. i couldn't care less about going fast. immediately sought out options to widen my stance. this is definitely (yet) an important part of bike fitting.

Very useful video.

Stance is one of the 3 aspects of saddle position; height/fore-aft, q-factor-stance, cleat position

I purchased some carbon ultegra pedals with the extra 4mm axle width from sports direct £108 ,definitely helped with knee pain I was having.

Speedplay pedals have different axle length. Also, on a 1x cranckset, looking towards MTB cranckset could be an idea because qfactor are by far wider than road, useful for a gravel for example. I’m a tall person and it’s very important for me to be wider than stock configuration !

I had to increase my q factor by like 12mm on both sides. Helped a lot with comfort.

some different aftermarket cranks can also dramatically alter your stance. Super nice, somewhat pricey, but worth it for some. (see White Industries, Ingrid Components, Appleman Components)

got lake shoes in wide cut so that increases stance too l guess. pushed the cleats out. experimented with the ultegra pedals with longer axle. depends a bit on bike but improved my riding a lot.

4:45 and great bartape!

Common guys, we need James in a podcast

Odd that Speedplay wan't mentioned, although I know James is not a fan. They used to be the only brand where you coul make more than a 4mm adjustment (at least as far as I know). You could get aftermarket axles in a variety of lengths. I think this has stopped since the Wahoo takeover, but you can still get aftermarket axles in a variety of lengths. I run them for this reason, although I didn't know about SQlab which may be a better option

Hi, I recently got Garmin Rally powermeter padles and one of the metric it measures is the "shift of the base" or in other words how far from center of the pedal the power is applyed. I have got average + 23mm from center on left and about + 13 mm on the right foot ("+" meaning out further from the bike). I am wondering whether this would be good indication that I would benefit from spacing my feet out to get more comfort and possibly better power? I do not particulary suffer from huge knee pains or anything like this but still could be worth to have better fit. Honestly it sound kind of logical but what would be your take on this? I have S-works cykling shoes and as pointed out in some of your videos these tend to have angled soles towards the outside. This could also be a factor there. Right? Any Ideas or recomendations? Thanks. BTW. Thank you for grat content. These videos are great!

I was warned about the Q factor on Fatbikes when i was considering buying one. Knee and hip destruction was all but guaranteed. Instead I figured out that my road bike was narrower than my body likes. The Fatbike (in 29er mode) gets ridden more often than any of my bikes.

Sqlab need to improve their mtb spd pedal. The cleat to pedal interface has so much play/slop that mine are collecting dust. Too bad as this 8mm option is bang on. Otherwise I have the RISK 16mm titanium pedal extenders, been using them for years with zero problem so far. Paired with shorter pedals (xt are 52mm vs more common 55mm mtb pedals) and cleats all the way out to mitigate 16mm being too long.

I run 20mm pedal spacers. The are available from kneesavers in the usa and steve hogg in Australia

Tip - ride with some cheap flat pedals and training shoes (sneakers). Observe the position your feet move to

Looking into the wider stance Look Keo type pedals as I've slammed my cleats as far as they can go with taking a Dremel to them to notch out the cleat and retainers.

Increased stance has also helped me to produce more power output. Not sure how but I can see the difference. Leverage maybe?

Wow, imagine catching a video that is less than 1 day old! That doesn't happen often. This is an element of bike fitting that has intrigued me for years but is very difficult to get good information about. Your video focuses on widening stance incrementally with techniques between the crank arm and foot. I am interested in what the total width should be between feet. This is largely affected by the width between crank arms and that seems to be missing here. There is a great deal of diversity amongst cranksets. Most of the cheap and cheerful ones that come standard with commuter bikes tend to be quite wide (it has been a while since I last measured on a friend's bike but I think it was in the order of 185mm+ for a triple. One of my knees was injured once and the outside is tender (gets excited at the least excuse) so I have always tried to keep the crank arms as close together as possible - I am not tall so my legs are also on the shorter side and I don't want them to splay too much. In the old days a double crank would be about 154mm, but on my last bike I had to hunt around to find a triple (touring) under 170mm. Can you provide more information on fitting crank arm widths relative to leg inseam lengths. Of course we are all different but I wonder if there might be some general guidelines out there that you may know of? Cheers.

Francis invited questions, so here goes. My husband had a bike fit prior to buying his first carbon bike some years ago. The advice included seriously increasing Q factor - speedplay pedals with the long axle option and moving cleats as far in as possible. Shoe needed to be carbon to support this. (He's ~100kg, 65YO and bandy legged). That set up has been good. Now he's interested in power meter pedals (indulgence, not necessity). Wahoo don't appear to offer a long axle version of the Powrlink pedal. We assume that using short (~1cm) axle extenders would interfere with power accuracy. It's pretty much time to get new shoes so changing pedal systems is not out of the question if it would not compromise stance. Any advice? Love James' videos. Keep them coming.

Flat pedals allow various stance widths without hassle and you can change at will while pedaling. Those who need clipless can benefit from trying out flat pedals to feel which stance width feels least straining. So they have a clue for how wide pedals and possibly washers they need.

I'm 1,93m and got the SQLab 15mm pedals a year ago: No more knee pain and numb feet also reduced massively - still need a proper bike fit for that I guess. Highly recommend these pedals if you're a taller fella.

I've adjusted my cleats for Q-Factor always. But with the new bike build, I decided to get the +4mm pedals, I hope worth it since they are $60 more street cost ATM than the regular pedals.

Thanks Francis and James...will leg length discrepancy affect this as well??

It really bugs me that they keep asking to post questions in the comments, but never answer any.

Question - any chance of some do's and dont's for XC bike fit. It is ridden seated a lot of the time and any information of using a road bike fit to create a XC one would be good.

As someone who is bow legged I had knee pain until I switched to long axle speedplay and then poof!

Not to do with this topic, but the reason I am commenting, is that James gave reference to a company called SQ Labs. Please could James do a video about their saddles. They are not as readily available in this country as other makes, but I am very pleased with mine. I'm just over 70 years old now and got back into doing sportives a few years ago. I tried quite a few saddles and couldn't get on with cut out ones, though I know from James's previous videos, that he mainly sells cut outs. The whole point about the SQ Labs saddles (look at their website), is that your rear is lifted slightly higher, which to me negates the need for a cut out. To my mind a great design.

I would love to see a bike kitters view / considerations for larger riders / I'm clearly overweight and would be really interested if there any other items to consider for a bike fit for a larger / either bulk or overweight person. Along with Q factor, would seat sizing need to change.......

I see James i press like

Would it have been helpful to give some representative numbers for Q (and advice on how best to measure it)?

I bought pedal extenders.. short pieces of metal with an inner and an outer thread you screw in between your pedal and your crank extending the stance width 16 mm per side. Since I don't do 2000+ watts I feel I'll be fine and happy. With my legs being kinda big I need the extra stance width otherwise my thighs rub against any saddle. Also it feels... better. Like I can push better.

James - is there ever a case for increasing the stance on one side, only? I have a slight hip impingement and tib post tendonitis, so my right heel dips in and scuffs my crank. I get inner calf irritation and saddle sores on just that side, but my left side feels strong and smooth. I have experimented with adopting a more medial cleat position but I can't say it did much to change things yet. What do you think?

Go back to a square taper BB and stance becomes trivial to adjust. (Later BB standards were mostly adopted to increase stiffness, which is meaningless for most riders because we aren't 19 year old 70kg professional athletes)

Question about bike fit: I ride flats, and I’ve noticed my feet naturally track on the outside edge of the pedals. Should I try a wider Q factor?

Interesting. Tags with my experience as a chubbier / wider rider. I've combined the cleat position, washers, and also mixed a Record Triple chainset onto a Centaur 115.5mm BB. (The std Record triple is 11mm). I'm still riding on the outside of my feet (Which are also very wide and terminally flat.) Would come in for a fit, but I'm based near Glasgow... And yeah, 2 bike fits in last 5 years, neither of which addressed Q

SQ labs appear to be out of stock for extened sizes for SPD and raod pedals for the US

Had my stance adjusted by your team a few months ago and all the pressure in my hands went away.

What do you think about these parts that increase the q factor you but in between the crank and pedals? Not the washers but solid parts that simply increase the stance width?

Just changed from Crankbrothers to Time on my CX/Gravel/general outdoor use and singlespeed cx bikes when a few years old CB went out one pedal adding to bunch ok to bad condition spare CB pedals from worn sets. So q factor is now different what is best to adjust for it till i get bike done as a new fork is needed on cx/gravel/general outdoor use bike of the bike. Singlespeed cx is set up already but now different q factor.

Totally get the importance of stance width, and I've gone as far as to buy some pedal extenders, although I think this is kind of suboptimal, just shooting in the dark..What I'm REALLY looking for is a way to measure what my stance SHOULD be. If you have any thoughts or references, that would be very helpful. Thanks!

Wait, how bout pedal extenders? I have them on my bike, ordered the titanium ones for durability. They're 16mm. Can't use clipless pedals without them because I'm bow legged.

Sorry but I disagree with "more narrow Q-factors" that's simply not true, bikes Bottombrackets are getting WIDER NOT MORE NARROW! I hate the "wider Q-factors are better" I almost feel it directly if it's to wide but never had a problem with narrower q-factors, my hire bike on Mallorca was a Cannondale with a wider Q-factor and I felt it immediately (in a bad way) and a lot of bikes have a wider Q-factor because of a bigger bottombracket. Even my SRAM bike is a bit wider and it took me a while to adjust to it!

Since a longer axle will put my foot further outward, is there any danger I will bend the crank?

I bought a wide spacer because of coming from mountain bike and when i rode my road bike and felt better. Few rides later and about 40km distance, my left knee starting to hurt like hell and realized Q factor is wrong and went back to normal Q factor on road bike and no more knee pain unfortunately the right knee starting to hurt more on my mountain bike and had to go back to flat pedals and no more pain on both knees. I was planning to go full time SPD on mtb and road bike but i get knee pain. So now road bike SPD blue cleats and flat pedals on mtb. I should have not bought the stupid spacers.

I am bull legged, more on the right side, than my left, Easy fix, I put a pedal extension on the right side so that my right leg goes straight up and down. 😊

What's the easiest way to measure this? Trying to set up my gravel bike the same as my road setup. 2mm spacers not enough, gave myself PF syndrome and tracking issues after one hard ride this winter. I've already spent $$$ trying to source discontinued pedals and spindles. I'm guessing pedal extenders would be too much. Can't really proceed until I have a proper measurement. Please advise!

Can too small a stance create a quad muscle imbalance. ie Large vastus lateralis and smaller vastus medialis?

When going for a wider stance does the body need to be conditioned to the new stance? Or would it automatically benefit for a better stance?

would pedal extenders affect the reading of power meter pedals?

Just switched my mtb pedals to assioma (with a specially made spacer so it fits) to replace my sqlab +8 pedals on my gravel! Works great with deore XT shimano pedals. Could sharen measurements for the metals spacer if someone is interested.

When James says larger people does he mean taller or heavier? I’m on the taller side and think I could benefit from a wider stance. In particular I can feel my right knee wanting to open up and slight occasional uncomfortable feeling.

always curious about the extra width from fat bikes as people use them for long distance bike packing. Can’t be greeeeat can it?

I always had the impression that my feet were too close to each other, and I am a big cyclist. I use 18mm pedal spacers. I asked the bike fitter if I was right to use them. He said - I don't know how you could ride without them...

The wider q-factor is the reason I don't use these Favero powermeter pedals.

I might miss it in the video, but how to know whether the stance or q-factor is right, too wide or too narrow? I've recently faced knee pain on a new mountain bike with wider q factor than on my other bike, and I thought it might have been related. I removed the spacer washer and the pain seems to have gone, but I'm not quite sure why. It's like 1mm of the difference. How can I make sure that my foot position is right?

Using power meters since 3 weeks. Pain at the outside of my right knee (only) starts after every +2h ride until a point i can’t even put pressure on my pedal anymore. I use the Assioma power meters. Is there ANY SOLUTION?! 😫

Im getting itb pain particularly in my right knee towards the end of longer rides. I think my legs are tending towards knees falling inward as im tired. What will help correct this? Thanks

What book would you recommend for bike fitting?

As I’m narrow shoulders I was always lead to believe my Q-Factor is better to be narrow as in cleats positioned all the way out so my feet are closer to the crank arms.

I run flat pedals. How about a BB with a wider axle?

YES!!! its itééé

What do you think about die SW Lab Saddls?