3 ms·

Dunno if Shimano is ever going to live down BioPace. At the same time I’m glad clever people kept at it. https://absoluteblack.cc/oval-104bcd-chainring.html ht

• cag_ii 9y ago
  This is the second comment in this thread criticizing the biopace, what exactly was the problem with it? It seems to me that the oval chainring is seeing a resurgence lately (in the MTB community at least).
  • ScottBurson 9y ago
    I never tried one, but I was told they were hard on the knees.
  • analog31 9y ago
    A couple bikes in my family's fleet have Biopace rings, both having been made around the same time period. What I recall at the time was that they were greeted by a collective yawn because they weren't eccentric enough to have much of an effect. I just measured a 48T Biopace ring that was in my spare parts bin, and the ratio of major to minor diameter is about 3 percent. The only annoyance I can think of is that you can't use those rings with a single-speed or gearhub without a chain tensioner. If they're wrecking your knees, don't push such long gears. Or, rotate the ring by 72 degrees on the crank to pretty much negate the effect.