Chain rub against the front derailleur cage is one of those small annoyances that only shows up when you're in the big-big cross-chain combination, and while cross-chaining is technically avoidable, most riders end up there at some point during a hard effort. The Shimano FD-9000 Front Derailleur Skid Plate is the factory replacement for the small plastic wear surface that lives on the inside of the outer cage plate on Dura-Ace 9000 11-speed front derailleurs, and it's the part that quiets that contact and keeps the aluminum cage from wearing prematurely.

This is a Dura-Ace 9000 series specific piece. It fits both the braze-on and clamp-band versions of the FD-9000 double front derailleur, but it does not interchange with the Ultegra R8000, 105, or the newer R9100 generation derailleurs. If you have an older FD-9000 on the bike and the plastic has worn thin, cracked, or fallen off entirely, this is the correct replacement part.

Installation takes a few minutes but can be fiddly the first time. The plate seats into the inner face of the outer cage and needs to sit flush to do its job. Take your time getting it aligned, and once it's in place you'll notice the chain-rub noise drops significantly when you're running the big ring paired with the larger cassette cogs. It won't fix a poorly adjusted derailleur or a worn chain, but for a derailleur that's otherwise shifting well, replacing a chewed-up skid plate is one of the least expensive ways to bring the drivetrain back to quiet running.