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calamarichris 01-06-19 01:40 PM

A Wider Q-Factor Possibly Beneficial?
I've always gone with the narrowest Q-factor possible, but I recently built up a bike that had a non-performance crank and bottom bracket that were much wider (over 2cm wider at least than my usual Dura Ace 7800 crank & BB.) And I noticed that my legs were less prone to tightening up when digging deep/pedaling hard.

I'm a larger rider, 185 pounds, 6'2" with proportional hips, and I wonder if perhaps riders my size do not benefit from the narrowest Q-factor possible? There isn't much information on it (the best I was able to find so far is the below pasting on the Wikipedia entry, but my local bike fitter said that the narrowest-Q-factor is basically a wives tale that doesn't apply to everyone.
******Pasted from Wikipedia:
A larger Q Factor (wider tread) will mean less cornering clearance (while pedaling) for the same bottom bracket height and crank arm length. A smaller Q Factor (narrower tread) is desirable on faired recumbent bicycles because then the fairing can also be narrower, hence smaller and lighter.[4] Sheldon Brown said that a narrower tread is ergonomically superior because it more closely matches the nearly-inline track of human footsteps.[5]Research from The University of Birmingham in the United Kingdom suggests narrower Q Factors are more efficient, likely due to improved application of force during the pedal stroke, as well the potential for reduced knee variability and risk of injury.******

calamarichris 01-06-19 01:43 PM

Has anyone else experimented with widening the "tread"/Q-factor? What did you learn?

How did you do it? Shift cleats inward?

Are Hollowtech spacers suitable for outboard bottom brackets to help?
I don't want to use the pedal spacers, because I don't need to go 2cm wider--perhaps 5 to 10 mm wider.

79pmooney 01-06-19 01:57 PM

Interesting challenge, going to substantially wider Q-factor. I will not be of much help. I'm of the as-narrow-as-possible type. (My knees do not like wide Q-factors at all and have never seen too narrow. A bike they love is my latest fix gear with a narrow Phil Wood BB, set up asymmetrical for chainline on the right and crank close to the chainstay on the left. I do my best to stay away from Shimano cranks and look for older Sugino cranks because they are straighter with smaller clearances to chain and chainstay.

We all have to find what works of us. I love seeing the creativity people use to meet that need.


trailangel 01-06-19 02:26 PM

Standing up going uphill you will find if the Q gets too wide you are fighting the bars/bike.

calamarichris 01-10-19 12:52 AM

Originally Posted by trailangel (Post 20735038)
Standing up going uphill you will find if the Q gets too wide you are fighting the bars/bike.

I actually experienced the reverse when standing with these wider cranks. One thing I've been incorporating in my focus when training is dynamically and fluidly bracing one pedal against the other when pedaling. It might simply be psychosomatic, but I've found that when my focus is good and I'm able to do it well, it feels stronger and easier, AND my HR-to-watts ratio also confirms its benefit. And when I did it with the wider cranks, the additional leverage was slightly offset by the awkward lateral feeling of the wideness. it didn't exactly feel like I was fighting the bars (which are 52cm wide, to accommodate the dog chariot.) or bike though.

So today I drove up to Santa Monica visit Nate Loyal to check on this. He explained to me why and how I do not need a wider Q-factor. Also did an 8-year check up on my fit on 3 bikes. He left a lazer pointed at my knees while I pedaled for a few minutes and he believed going wider would be a mistake.

My saddle on my "base" bike, (my beloved 86 Schwinn Peloton) had somehow crept back and down over half a centimeter since I last saw Nate in 2010.

A lot happened over the last 8 years. He's fathered two kids, I've broken 6 (or so) bones, including a femur, which I feared would affect my leg strength imbalance. Thankfully it appears I dodged that bullet, but Nate told me a few stories about clients of his who'd broken femurs, who'd had some interesting anatomic anomalies. In addition to Nate's expertise and meticulosity when performing the personal fit, it was also an enlightening experience.

LA traffic just gets worse and worse every time I go up there, (which happily is not often), but Nate is worth the drive.

fietsbob 01-10-19 12:47 PM

I intentionally widened the Q on my touring bike because I started the trip on the last weeks of February and wore shoe-covers to keep mt feet warmer and drier,

with pedal extenders , so those shoe covers did not rub against the crank arms , with every pedal stroke .. you get used to it .. Bike tour was 3 seasons long..

I now have a somewhat wide setup to get the chain-line right, for the requirements of the Rohloff hub in the back..

Single chainring on inside of crank spider , disc chain guard on the outside...


philbob57 01-11-19 04:38 PM

I put 15 mm pedal extenders on my bike last year. I feel more natural on my bike. My knees go straight up and down almost automatically. Without the extenders, I need to concentrate to do that.

I'm a clyde, though - big thighs.

tyrion 01-11-19 05:20 PM

Wider Q-factors are much more comfortable to me. Narrow Q-factors give me a funny feeling in my knees - doesn't feel right. I use pedal extenders on some bikes. (I'm big, 6'5").

Nikola88 04-11-19 09:53 AM

I use 20mm pedal extenders on my road/fixed bikes, my hips are a little bit wider and i found that my knees feel better now, especially when riding single speed (it even helped with toe overlap on one bike), its easy to try, there are cheap 15mm ones on ebay

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