What We Don’t Like
Not Backward Compatible
Shimano could, if they wanted, make existing Di2 11-speed shifters compatible with the 12-speed derailleurs. We know this because they made the existing 11-speed time trial/triathlon shifter parts compatible with the 12-speed derailleurs (it requires a firmware upgrade and Shimano’s new EW-SD50 to EW-SD300 wire adapter). But they don’t offer this option for their drop bar shifters, meaning riders with 11-speed Di2 groups who want to upgrade to 12-speed will need to buy a full groupset.
No Rear Derailleur Clutch
Aided by disc brakes and improved tire clearance, we’re riding our “road” bikes in new and different ways that often takes them off the pavement. Clutch mechanisms, found on some rear derailleurs, help to keep the chain from dropping off on rough terrain. Shimano not building a clutch into Ultegra and Dura-Ace rear derailleurs likely stems from wanting faster shifting speeds and improved battery life, which are good things. But even so, we think Shimano missed an opportunity to incorporate a feature suited to the modern road rider’s experience into the new groups. It will be interesting to see what kind of update GRX will receive in the future. Will that rear derailleur play nicely with Dura-Ace and Ultegra, or will riders wanting extra chain retention need to run a full GRX groupset?
Overall, we think Shimano made solid updates to Dura-Ace and Ultegra. They added worthwhile features without adding much weight (barely 20 grams for DuraAce) or increasing the price substantially. Semi-wireless makes the groups simpler for riders and mechanics. The improved disc brakes are nearly worth the upgrade price on their own. But, as always, DuraAce is a groupset designed for racing at the highest level, with a price tag to match its performance.