Plenty of bikes are still running 10-speed drivetrains, and if yours shifts well and fits the riding you do, there's no compelling reason to abandon it for an 11 or 12-speed upgrade. The Shimano Ultegra CS-6700 keeps that drivetrain running with Ultegra-level build quality—same Hyperglide shifting refinement, same durability, same compatibility with any 10-speed Shimano road setup you already have.

The CS-6700 uses an aluminum spider to mount the three largest cogs, which shaves weight compared to an all-steel construction while maintaining the stiffness needed for consistent shifts under load. The smaller cogs are individual steel pieces with machined cutouts that trim additional grams without compromising tooth engagement. A nickel-plated finish adds corrosion resistance, which matters if you ride through wet conditions or store your bike where humidity fluctuates.

Hyperglide tooth profiles do the work that makes Shimano cassettes shift so predictably. Each cog has contoured shift gates—precisely positioned ramps and pins that catch the chain and guide it onto the next cog during shifts. The geometry is computer-designed to minimize the hesitation and noise you get with less refined cassettes. Under load, when you're pushing hard and need to grab a different gear, the chain moves where you tell it to move.... Read More