What would you pay a wizard to come to your house and place a spell on your bike that would do away with mechanical problems forever We don't sell that, so don't bother searching the site. What we do sell, however, is the Shimano Dura Ace Di2 FD 9070 Front Derailleur. It's no wizard, but it'll definitely help with mechanical issues or shifting issues, anyway. With proper installation, you can forget about dropped chains forever. Shifting also becomes quicker, easier, and more precise. Even the woes of chain rub will become just a dark memory. The first thing you'll notice when comparing the 9070 system with Shimano's 7970 system is that 9070 is far more compact. It's a bit lighter, too about 10 grams. Cable routing is also simpler and cleaner, and, perhaps most importantly, setup is easier due to Shimano's newest generation of its E Tube electronics system. So, put down the wrench. Your shifting adjustments will be made on your laptop. Finally, Shimano's automatic trimming makes adjustments on the fly, so chain rub and dropped chains are a thing of the past, no matter how cross chained you've become.