I would love to see the changes for each group level through the years so I could compare say a circa 2006 105 9spd group versus a 2009 Tiagra group. Or a 2010 105 group vs a 2007 Dura-Ace group or Ultegra group, etc. Is there such a reference anywhere?
Shimano doesn't have models years like cars, though there are often references to model years.
Each part has a part number stamped on it. That's how they're identified. Some parts don't change over several years and if the part number doesn't change, that part joins the next model year after New Year's eve.
A forum community dedicated to Road Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, troubleshooting, maintenance, and more!