Long-time bicycle chain brand KMC has just introduced their new React cassettes in 10-speed and 11-speed versions. First spotted at Eurobike 2023, they’re designed for wide-range 1x and 2x applications, with tooth counts good for road, gravel, and mountain bikes.
At just $65, they’re affordable replacement, option for your trainer, or way to try a different tooth count on the cheap. Perfect for upgrading your kids’ bikes, too. And from the looks of it, you won’t be giving up shift quality to save some coin.
![KMC react cassette shift ramp highlights](jpg/kmc-react-cassette-tooth-ramp-highlights.jpg)
The cogs have dual shifting ramps called Flow Control, smoothing upshift and downshifts. These ramped tooth profiles & thicknesses use varied shapes to guide the chain from cog to cog.
![KMC react cassette tooth counts](https://bikerumor.com/wp-content/uploads/2024/02/kmc-react-gear-ratio-tooth-counts-chart.jpg)
Both KMC REACT versions have two gear range options:
- 10-speed: 11-36T, 11-42T
- 11-speed: 11-42T, 11-50T
![KMC REACT 10-speed chains](https://bikerumor.com/wp-content/uploads/2024/02/kmc-react-36-42-tooth-cassettes.jpg)
They’re optimized for KMC chains, but are compatible with other 10- and 11-speed chains. They fit Shimano HG freehub bodies. Fitting it to a bike built around a smaller cassette? They recommend adding the Wolf Tooth Components Goatlink to increase your derailleur’s capacity for larger cogs.