Shorter Crank Arm Made Huge Difference

I got a new bike about 7 weeks ago and my knees had slowly been deteriorating.  I had a professional fit and had it revised after the first 4 weeks, but my knees were getting BAD.  The aching was keeping me up at night, walking was getting uncomfortable, and I was worried that arthritis was setting in and my training days were numbered.  With some advice from folks at BT and doing some research online, the problem turned out to be the crank arms on my new bike were 175mm while my old bike had 170mm.  While according to formulas, 175mm cranks should be OK for my 32" inseam, that apparently wasn't the case for me.  Today I got replacement 170mm crank arms and the difference was AMAZING.  In my 1.1 loop around my neighborhood, I was about 1mph faster and my knees didn't bother me at all.  I can actually get higher torque with the shorter cranks because with the longer arms I could not pull up on my pedals without discomfort.  With the longer arms I get higher torque with one leg, but it didn't match what I could get with shorter arms and two legs working together.  My first race is Saturday, and I'm hopeful I'll now be faster on my new bike than I was with my 32 year old bike I was riding.