Hi; I recently picked up my first recumbent (Vision R40). I adjusted the boom length so that my knees were slightly bent. Into the third week I laid the seat back further. Into my first 30 miles of a ride I noticed my left achilles tendon began to hurt. It has continued to hurt since this ride. I am wondering if I am having to reach too far now that my seat is laid back. The bend in my knees seems to be ok, but this is the only change I have made. I guess my general question is, how does one ensure a proper fit on a recumbent. I understand x-seam measurements, but not convinced scientific methods are best.
Last assumption: Left tendon only hurts as one's right leg is typically longer and in this case, is most likely long enough.
Case solved. I took the bike into the shop to have it converted from USS to OSS. They put it on a trainer to make sure the fit was ok. Low and behold, they ended up shortening the boom by 3". So I was definitely over reaching. No more pain and much better power on the down stroke.
Now that you have been professionally fitted, give us the insight.
For example, if you have the pedal in the opposite (at the farthest point away from you) position, without any shoes on, seated normally on the bent, foot at a 90 degree angle to your leg, where does the axle of the pedal hit your straight leg?
Is it the heel, an inch above the heel, etc?
Any other pertinent information would be appreciated such as inseam, distance from seat back to the center of the crank, crank arm length, etc.
My friend set the boom for my x-seam (41.75"). He then put me on a trainer and had me place my heels on the pedals. He said your knee should be almost locked out when your heels are on the pedals, whcih they were. I then clipped in and everything felt perfect. Hope this helps.