Wait, wait, wait. After reading that I just re-read your original post.
"The longest part of your leg extension is not at the bottom of your stroke?" Your saddle was probably already too far back. Adjust your weight distribution with the stem (length, rise, height if you have room for more spacers) and possibly the TILT of the saddle. Depending on your preferred riding position, different handlebars might help too. Set your fore/aft saddle position to set your knee in the correct position over the pedal spindle.
You should be able to get a professional fitting done for about the same price as a new crankset...
Last edited by OakLeaf; 11-20-2008 at 05:07 PM.
Speed comes from what you put behind you. - Judi Ketteler