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Crankset Q-factor and knee pain?(8 posts)

Crankset Q-factor and knee pain?dawgcatchr
May 13, 2003 6:52 PM
I have been the victim of some fairly severe knee pain recently. I have pain on the inside of both knees, about 1 centimeter inside of the bone near the middle of each knee. I had been riding my mountain bike for 3 weeks, about 5-7 hours per week, with no pain. Then, on my first road ride of the season (a fairly easy 1 1/2 hours) I was hit with the knee pain after riding. I know the height of my saddle is pretty much correct on my road bike (my heel just grazes the pedal at 6-o'clock) and I get full extension on my stroke, so I am looking for solutions to the pain elsewhere. One obvious difference between my road bike and mountain bike is the likely difference in crankset q-factor.

How does one go about determining the proper q-factor for their anatomy? Any way to play with q-factor without changing cranksets? I am a farily thin 5 foot 8 guy with a 28 inch waist and 30 inch inseam-my hips are on the narrow side. I am riding current Dura-Ace cranks in 172.5mm length (I am assuming that is the proper length crank for myself), Look pedals (with 6-degree float). I have orthotics that put my knees fairly neutral (they used to fall badly toward the top tube). It makes sense that both myself and a wider guy wouldn't want the same q-factor, even though we may ride the same crankset. So, what can I do to get rid of my knee pain?
re: Crankset Q-factor and knee pain?Eug
May 13, 2003 7:47 PM
I'm 5'7" with 30.5-31" inseam. I get the same pain with 170 mm 105 cranks. No orthotics, but I am slightly bowlegged. My left knee seems straight thru the pedal stroke, yet I get the most pain with my left knee.

I just received my 165 Ultegras so I'll try those out.

In the meantime I'm off to physio.
please explain, what is "q-factor"?dtufts
May 13, 2003 8:59 PM
Roughly speaking, it's how far out from the bikeOldEdScott
May 14, 2003 5:43 AM
your feet are when you're pedaling.

Doesn't Time make some pedals that give you at least some Q factor adjustment?
re: Crankset Q-factor and knee pain?St Monica Rider
May 13, 2003 9:24 PM
I had the same problem. I got my road bike last April and experienced knee pain within my second ride. The difference with you is I don't experience the pain riding, only after my ride. I have record cranks at 170 mm. I did a lot of research here and thought initially to get 165 mm cranks using Dura Ace, as Record does not come in 165 mm, based on an article that calculates crank length from inseam. A fit specialist I have come to know suggested to get the longer cranks based on my riding style, which has been shaped by mountain biking.

Also, my LEFT outer leg is 1 cm shorter than the right based on a pelvic twist. So, I shimmed my left shoe by about 1 cm as a first step. The second step was to see my doctor here in SF. She recommended knee strengthening exercises, plus to take essentially prescription-level Advil for two weeks. The key was the knee exercises for one month. My knees are getting stronger and I noticed that the pain has largely disappeared (probably caused by the pills). But, I also noticed that my cadence has gone up and my knees feel stronger everyday.

So, you should see your doctor and maybe check if your legs are equal in length.

I hope that helps.
Could you describe the knee exercises???MrDan
May 14, 2003 6:43 AM
I'm having some knee pain as well. What exercises do you do for your knees?
-D
have you tried to stretch?cyclopathic
May 14, 2003 9:58 AM
the other major diff besides Q-factor btw mnt bike and road is the upper body position. Riding in upright position shortens hamstrings I have shot my knees by riding mnt bike for several weeks w/o stretching and then jumping and doing 150mi road ride. Stretch hamstring for a couple weeks and reduce load should help good luck
re: Crankset Q-factor and knee pain?al0
May 15, 2003 4:02 AM
Try to slightly lower your saddle. The "my heel just grazes the pedal at 6-o'clock" is only good starting point, not the final solution for saddle adjustment.