Originally Posted by rykoala
Yeah its got biopace rings. What are those? I don't know the difference really. I had another bike with those and didn't know the difference.
Biopace were ovalised rings as opposed to just round chainrings. The idea behind Biopace and the shaping of the rings was to eliminate deadspots in your pedalling. Unfortunately, it also hampered riders who developed proper spinning techniques. By learning proper spinning, deadspots are reduced and can sometimes be eliminated. Shimano's original Biopace rings introduced in the mid-1980s were designed for newer riders and thus made to accomodate a lower cadence (around 60). As riders progressed and started spinning upwards of 95RPMs, the Biopace rings caused them to bob up and down or back and forth. Shimano also released Biopace HP (high-performance) rings which had a less pronounced ovalisation. By the end of the 1980s, Biopace rings got so round that Shimano (and other companies who had by this time cloned the idea) abandoned the whole concept altogether.