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I read Dan's article " Proper Bike Fit for Triathlon-Specific Bikes" and I have a question about Knee position. I understand that proper fit has to do with the 90 degree relationship between shoulder, hip, and pedal axle. When bike geometry gets steeper, my body position moves forward, the 90 degree stays contant, but my knee moves forward of the pedal axle at the 3 o'clock position. I did an IM last season and have been dealing with an over-use knee injury ever since. I'm concerned that by having my knee forward, I'm putting stress on my knee. I have a Trek Hilo 1000, My seat is positioned full aft and my knee is 1 1/4" in front of the pedal axle at the 3 o'clock position. Is their a limit to knee position? Would I benefit from buying a new bike that brought my knee back(slack geometry). Any thoughts?
Thanks,
Steve
Not quite sure what you're asking but as you move to a steeper angle the "KOPS line" plumblined from the front of the knee should move further forward of the pedal center. If you move shallow it moves back and if right back in the "big slam" type position it should likely be behind the pedal center.
I'm not sure how any of this effects your knee injury providing that the knee angle remains constant between the recommended (by different authorities) 145-155 degrees which is accomplished by adjusting your seat height accordingly.
Sorry, I just don't understand what you're getting at. Can somebody else help out here.
To clarify my question. I've read a few bike fit articles that recommend the "KOPS" line be perpendicular when the pedal stroke is in the 3 o'clock position. In their theory, having your knee forward of perpendicular would increase pressure/torque at the knee cap during the power portion of a stroke.
I am neither FIST certified, nor am i qualified at all to be providing fit advice, but my take on your question is this....
I am guessing those articles were geared toward a slacker geometry. On a hilo, your entire body is rotated more forward relative to the bottom bracket so the traditional 3 oclock position will not be your effective 3 oclock position for this purpose. In other words, since your entire body is rotated forward, you are ok in front of the spindle.
jg
Thanks for the feedback.
Steve