The 10-speed drivetrain era isn't over just because Shimano moved the current groupsets to 11 and 12 — plenty of bikes are still running Ultegra 6700, 105 5700, and Tiagra 4600 setups that need fresh chains to keep shifting cleanly. Shimano's Ultegra CN-6701 is the direct replacement chain for those drivetrains, using an asymmetric plate design borrowed from the Dura-Ace 7900 chain to sharpen shift timing on double crank setups. If you're rebuilding an older road bike or extending the life of a proven 10-speed groupset, this is the chain Shimano designed around it.

The asymmetric construction is the story here. Inner and outer plates are shaped differently — inner plates are contoured to engage the cassette cogs cleanly for faster rear shifts, while outer plates are shaped to work with the ramps and pins on the big chainring for smoother front shifts and less chain suck between the crank and bottom bracket. Perforations through the outer plates drop weight without giving up strength, and the pressed-pin construction keeps the chain quiet under load. It's a directional chain, so it needs to be installed with the stamped logos facing outboard to shift the way it was designed to shift.

Compatibility-wise, the CN-6701 works with any Shimano 10-speed road drivetrain and pairs with SRAM 10-speed road systems as well. It's spec'd for double cranksets — triple-ring setups use a different Shimano 10-speed chain. Installation uses Shimano's standard 10-speed connecting pin, which is a single-use pin that needs to be broken off flush after driving it through. Keep a spare pin in your toolbox if you plan to break the chain for cleaning or travel, because reusing the original pin isn't an option and pulling the chain apart at that link weakens it. A quick-link from a third party works if you'd rather have a reusable master link, though Shimano officially spec's the pressed pin.... Read More