Q-factor Science! The most important bike metric you've never heard of!

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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[germanhugger]

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...

[ggdd]

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.

[elwoodzo]

I was wondering when Obree would get a shout - bravo to you! A man ahead of his time....

[njm]

Very thorough treatment of this usually overlooked topic.

[reginaldscot]

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.

[MrBosslee]

Thanks for putting so much effort into the vid! Very informative as usual!

[joco]

ullrich and armstrong rivalry in the 80s and 90s? Their first tour de france together was in 2000.

[richardharding]

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.

[kenmoum]

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.

[stuartdryer]

I wish more manufacturers offered multiple pedal axle lengths.

[petef]

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.

[darrenleroy]

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.

[markmoreno]

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.

[philoso]

Increase Q also cause you to rock the frame L/R more to disrupt air flow to a higher drag.

[PeakTorque]

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.

[Dumbo.]

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

[mehmd]

So how do you determine stance width in your bike?

[VideoNOLA]

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.

[cpkGIRL]

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 but I imagine there might be some bit of correlation to the fastest & most dominant muscle group force vectors between the two conditions.

[fen]

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.