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Q-Factors and knee pain - that old chestnut!

by IanEdward
Mon, Jan 28, 2019 10:41
3

Sorry, I know this gets done to death on a fairly regular basis, but I'm just thinking myself round in circles at the moment!

Have had persistant knee pain issues that haven't been resolved by bike fit or physio (yet). In fairness, I've struggled with some of the advice given by the bike fit guy as it's all based around releasing tight muscles with a massage ball, and I can never tell if I'm doing it right (it hurts, but I imagine any muscle would hurt if you're placing your body weight on top of a lacrosse ball!). I do lots of stretching of the relevant muscles though.

My physio has had me working on glute muscles to improve hip rotation, and I already know from experiments on the road that sticking the sore knee out further from the top tube usually delays the onset of the pain. Problem is, my foot then gets sore! Especially around the outside of the foot. It just feels like there isn't enough space for my foot to adopt its preferred toe-out position, and to stick the knee out.

I'm thinking moving the right foot out, hence my other thread about speedplays. I also noticed that my singlespeed (currently the bike with the most miles on it) has an MTB BB e.g. 172mm q-factor, and the road bikes have a road bike Q-factor e.g. 146mm. I think my increasing knee pain has co-incided with more time on the road bikes, in particular turbo training for CX etc.

I can increase the Q-factor of the road bikes with some pedal extenders, 1 extender on the right doesn't quite bring me up to the 172mm width, but two extenders overshoots by about 13mm.

I'm tempted to try the one extender approach for now, will make the bike asymmetrical but I'm getting the impression that I'M asymmetrical, so maybe that doesn't matter...

If it works I was thinking Speedplays with superlong axles, which will make the road bikes pretty much identical Q-factor to the singlespeed/MTB.

 

I don't know what my question is to be honest, I guess: has anyone else used pedal extenders in this way? and has anyone else resolved foot/knee pain by increasing Q-Factor?

 

 

 

p.s. I know it's actually 'stance width' I'm interested in, but given all my pedals are 53mm wide Q-Factor and Stance width seem interchangeable.
 

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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3 comments

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peted76 | 5 years ago
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@Ian you mentioned a bike fit, I'm questioning the quality of that fit. 

A good bike fitter such as Mike at Bike Dynamics will cover all your contact points, measure your legs and consider your pedal stroke from all angles. 

You could require an 'odd' qfactor, but it's more likely that you've got different leg lengths (most people have), or that your cleats are out, or your saddle is in the wrong position..  it could be many things which cause your pain. Including an imbalance in your muscles (of which you can't easily throw money at to fix). 

FWIW, I use time pedals and their cleats have two options for q factor, I'm on the widest one, which gives me an extra 4 to 8mm width. 

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macrophotofly | 5 years ago
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You may be overthinking the Q-factor. It is less likely to be the direct cause IMO (having spent money trying to mess with my Q factor and found little benefit after all spending hard cash in reducing my knee pains). What made a signifigant difference to me was having pedals with more float (eventually moving to speedplay which solved it all, but I'm not trying to sell them to you - first try the most float on whatever pedals you use today - even try greasing the interface to reduce sideways friction). My actual problem was that I have relatively large thighs and on the upstroke the seat nose causes me to push my knee out slightly , which then returns back immediatly on the downstroke. The additional friction-free float of the Speedplays allowed my knees to move naturally throughout the stroke without resistance - hence no pain. Knowing this means I have also been able to avoid knee pains when using a bike without speedplays - e.g. my MTB with flat pedals I have a seat without a nose and it is inherently a wider-Q crank, hence both reduce the knee movement at the top of the stroke.

 

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pablo | 5 years ago
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I wouldn't like to guess howto solve your issue but if you don't have confidence of what the fitter has recomended i'd get a second opinion.

Knee pain in many seems to be caused by the saddle being set high but i guess you've tried lowering etc.  

Whats your core strength like?  I had loads of issues controlling my right leg after injury because my right side had lost loads of strength compared to my left side.  

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