Q-factor Science! The most important bike metric you've never heard of!
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- Опубліковано 1 сер 2024
- Let's discuss a bike industry 'secret' that might be the most important metric you never heard of. Yes we are talking today about Q-factor and stance width.
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Interesting fact, that Trek bike Armstrong is riding is not a Trek, it's a Titanium Litespeed bike painted to look like a Trek because Armstrong preferred Litespeed and Trek didn't have any good TT bikes at the time.
Oh my god it is
Tor yes Sir, feel free to Google it, its interesting Cycling history. 😊
ullrich and armstrong rivalry in the 80s and 90s? Their first tour de france together was in 2000.
Thanks for putting so much effort into the vid! Very informative as usual!
Bradley Wiggins used Speedplay Zero pedals with longer axles during his TDF win and hour record.. Mark Cavendish also uses special Shimano SPD-SL pedals with 1cm longer pedal spindles... The maximum shimano sells to the public are +4mm on ultegra and dura-ace pedals.. I cured iliotibial band issues and saddle sores by using Speedplay pedals with their longest 65mm spindles...
Very thorough treatment of this usually overlooked topic.
There is a trick that use to minimize my riding Q-Factor as much a possible:
I ride a hybrid bike, mostly on city roads and i don't use cleat pedals. I position my shoes on top of the pedals' axles, so the sides of my shoes rub lightly against the cranks, that way i get a feel for the right position of my feet on the pedals, without having to look down. This can be done constantly each time you ride with some practice.
By my measurements, i am shaving around 13mm per side, which in total is a around 26mm less of Q-factor, which for my mtb's 73mm bottom bracket is significant. This trick probably works even better on road bikes which have narrower bottom brackets / cranksets.
I spent ages when i started riding road trying to sort my cleat position out. Finally sorted it with a few washers between the pedal and the crank.
I wish more manufacturers offered multiple pedal axle lengths.
I was wondering when Obree would get a shout - bravo to you! A man ahead of his time....
I tried a Q factor of 132mm on the turbo using a very short BB spindle. I found my power was up for the 1st 20 minutes compared to my normal 145mm QF. At about 30 minutes both would be the same. At around the hour the 145mm QF always gave me more power. So time cycled might come into your equation as well. Maybe I needed more time to adapt, I gave it about 2 months before I tried the same setup on my Audax bike. I seemed a little slower doing 100km + rides & my legs ached a little bit more. Strange that they were faster for the 1st 20minutes on the turbo. I also had problems with the chainline hitting the crank when the smallest cog was selected on the Audax bike.
very informative, thank you very much.
Realy great Video keep it up. But you've missed the point of cornering clearence witch is specialx importent on crits and offroad bikesports. It alsow would be interesting to talk about if and how much it would be possible to counteract the biomechanical ineficiency via hanlebar with. Sorry for my bad english
Hi mate. How did you calculate the power figures for the Qs? For me the numbers are pretty ambiguous. A narrower Q +-10mm won't really make a difference because you're a not altering the front area. Your legs are still there after all.
As a recreational road bike rider who goes out twice or thrice a week I'll take comfort over performance any day. I save watts by hiding in the middle of the pack.
One other factor that dramatically affects someone like me with splayed feet is the need to get out of clipless pedals. I simply cannot get out of clipless pedals by turning my heel out. I allso have to put my cleats on crooked in order to avoid knee pain.
So I use 20mm pedal extensions, and Shimano Multi-release cleats for both comfort and safety.
I have the exact same problem that I've recently decided to address. A few questions if you don't mind:
1. 20mm seems like a lot, I understand it's necessary for you but does it also hinder you in some ways?
2. have you tried finding a solution with spd-sl or only 'normal' spd?
3. I read that the multi release cleats unclip by pulling up, do you adjust the pedal tension tightly to prevent unintentional unclipping or do you run the tension fairly loose and just make sure not to pull up on the pedals while riding?
I've ordered a set of those axle extenders and a set of blue spd-sl cleats, hoping that the reduced float as compared to the yellow ones would make it easier to unclip. They haven't come in yet, hope they'll solve my issues otherwise I'll definitely give those multi release spds a go!
@@demonstructie I have tried 18 mm extensions and 30 mm as well as the 20s I currently use. The 30 mm are perfect for riding on flat pedals which I do sometimes on my MTB and my version of a pub bike
Re. the Multi-release cleats, I have SPD pedals set as with as light a release as possible. The number of times I have pulled out accidentally is tiny, but I am 71 y.o. and don't do much crazy stuff on the bike.
I also subscribe to the recent research, some of which is on the GCN channel that shows no advantage to pulling up, and in fact shows that professional riders don't actually have an "even" pedal stroke.
Even with M cleats and pedal release set light, you can push down and pull backwards with no fear of an unintended release.
Great content as usual Alex. You mention how to increase Q-factor with washers - any suggestions for reducing Q factor without spending loads on new chainrings etc.?
Reducing Q on standard cranks is theoretically possible with a zig-zag pedal extension but I havent seen one. You could also have a extended that screws to the inside of the pedal and offers a new fitting next to the existing crank. Again havent yet heard of it in real life. So....nothing really. sorry!
Trek didnt spend any r&d money on it. They paid lynskey (the owner of Litespeed) to make a narrow bottom bracket titanium litespeed and painted it like a trek.
I agree with comment below. How does seat tube offset, with respect to efficiency not necessarily reach, improves the way a person rides? Explain how a road’s grade, up or down, changes this.
Increase Q also cause you to rock the frame L/R more to disrupt air flow to a higher drag.
So how do you determine stance width in your bike?
I think Clydesdale (in my book, that's > 300 lb.) riders could greatly benefit from increased Stance Width, although -- as you point out -- this topic is rarely covered when custom-building a bike. Hardly ever do consumer manufacturers address the issue of Q-factor when touting their latest, greatest, widest platform pedals.
Great video.Great UA-cam channel.Maybe in Your next video You could educate Your audience about a seatpost setback ( never seen a post on UA-cam that is about a seatpost setback ) , and how it impact a rider's comfort and rider's performance on a bike.Why there are 0mm,16mm,20mm or 25mm seatpost setback ??????Thanks for educational videos,thanks ...... :)
See ua-cam.com/channels/r43Lgwqryq_QM00L1xJb4A.html
Mende it depends on seat tube angle. Setback is not the same for different bikes, because seat tube angle is different. I have a video on it.
Mende Jakimoski ... too Much coocking nothing on the empty pot .
The fastest people on Earth are Track & Field SPRINTERS. Each forefoot strike hits the deck closer to the mid-line & propels off that contact point, in essence, creating a smaller Q factor compared to normal stance or regular ambulation. However, it's not a completely 1:1 comparison, as runners tend to also rotate the pelvis on the transverse plane during forward progression,... unlike cycling Sprinters who demonstrate a more sagittal plane-dominant pelvic action / counter-action w/ each stroke,..... but I imagine there might be some bit of correlation to the fastest & most dominant muscle group force vectors between the two conditions.
i have a possible dumb question, see i’m a very skinny guy i weigh about 52kg and 168cm and have the normal ultegra road pedals but see i’m bowlegged and do not feel comfortable at all while pedaling. So should i increase my Q-factor?
How about home training bikes?
You've got some great info and visuals here. I don't mean to come off as harsh, but simply want to give you some tips.
I find it very hard to stay focused and follow you as your audio is very convoluted and unnecessarily complex. I recommend getting to the point faster and not being so repetitive. Remember: quality over quantity.
Thanks for the constructive feedback, some good points.
Most people know something about fitting and your position on a bike. The reference being speed efficiency, power and aerodynamics. Do you have information on fitting and structural analysis? Integrating our bio-mechanics and the bike? The 3 or 4 main fitting systems don't seem to get very deep in research or study,
no not really, what did you have in mind? we are working on validating an online bike fitting calculator
I find for myself that more then 160 is unridable. I have many Years on 139mm with Campagnolo nuovo record. The comfiest i have been ever. Modern or semi modern shimano road doubles are ok with few mm more. When i was building my city bike i had to find very old cranckset from the 90's to get low q-factor. Modern mtb's are around 180
My foot rubs the inside of the crank...
Putting 'IQsquare' and 'coming to market' in the same sentence didn't age well. Still nothing delivered to backers and they stopped providing refunds over a year ago (Still taking new orders on their website though! talk about scammers)
I would love to see the biomechanical/aero penalty tradeoff for stem stack height though, definitely feel that same biomechanical limitation when the bars are too low
My fat bike is 210mm but I can still put out the watts. It's overrated IMO
@Maciej Jan Długosz Those "many people" are mistaken. It'll be because they didn't set up the saddle or handlebar height to match their road bike. My brother sells them in his bike shop and does the proper setup/fit for them. Sometimes the geometry doesn't allow for the same aggressive position so you have to ride slightly differently. A bit of tightness and maybe cramp is the worst thing you'll get if done right.
@Maciej Jan Długosz I was talking about fat bikes too. Met around 40 people who have bought one now and no signs of pain unless it wasn't set up close to their road bike geometry
@Maciej Jan Długosz I'm not talking about tweaking it. You don't need to. Originally I commented that the 210mm Q-factor for me allows the same power output, measured with the Powertap pedals.
Great vlogger. Worst microphone. Please make your videos listenable :)
Good feedback thanks
Q-factor is no factor.
Wait until you start racing and some guy who decided to get back into it after 20 years wins your race on a 25 year old bike.
It's the motor not the bike.
Same motor with better bike always win.
Genius
Then if you know both things are important, ¿why say "It's the motor not the bike"?.
How often are the motors equal?
Then there's experience and the rest of the mental side of the game.
Then you get to the emotional and political sides (remember teammates Wiggins and Froome?)
No one asks _what_ won, they ask _who_ won. That's why I say "It's the motor not the bike."
¿How often? the tour is full of pro cyclist with close level.
You know the F1? the best driver F. Alonso never wins this last years because the car is bad.
They can ask if Froome won, but maybe Froome won because had better bike.
Sorry, but say "It's the motor not the bike." is so stupid, all is important.