Originally Posted by
ls01
I am going to reverse myself on the tooth count. I believe that they only came 52 tooth large ring and 42 tooth small, but they also came in triples. I had one hanging in the garage on a cabinette door for years. Last year I took all my old-school stuff over to my buddy's shop and dropped it all off. But I can't find a single reference to a 53 biopace ring.
I tried them for a while. I found them unsettling.. It wasn't a huge upset in my cadence, it was subtle, but it was there.
The first ride >10 miles, I noticed something odd. But then I moved them clockwise one arm, as suggested by Jack Tone, based on someone's analysis that Shimano had done them wrong making them "larger" (hence pulling more chain) when the crank is at the weakest point in the rotation and smallest when at the strongest point. After that adjustment, I don't notice them, and I have no problem spinning them as fast as round ones.
Of course the OTHER difference is these are 170mm cranks and all my other bikes have 175s. Last weekend when I had to swap the Circuit for another bike after flatting in the first two miles of my ride, for the first minute the longer cranks felt like I had to really reach with my toes!
I'm really curious how the Lotus, which has 170s but with Dyna Drive pedals (which put the foot level with the pedal spindle) will feel!