Oh swell, a forum of old guys and gals having a cranky old conversation ... and I'm joining in. Sheez.

I would wager that the shorter the rider is ... the more noticeable the difference when riding two crankarms that are different in size by 5mm. My pubic bone height is under 76 cm, and perhaps the difference I feel between 165mm and 170mm would be more than the difference that would be felt by someone who is over six feet tall. It would appear that the angle of the short rider's knee would be more influenced by difference in crankarm lengths ... than would be the angle of the tall rider's knee.

My 1995 Trek came with 170mm crankarms. When my Saluki was built, it came with 165mm, and this was an easier spin for me than the 170mm on the Trek. In about two weeks, my Saluki/Serotta/Trek bikes will all have 165mm crankarms.