Been wanting to give your gravel bike a mullet drivetrain with Shimano components? Now you can add Chris King’s R45D hubs into that mix, too.
Chris King’s R45D road hubs now have a Micro Spline freehub body option, available on standalone hubs and complete wheels.
![chris king micro spline freehub body shown with cassette attached](https://bikerumor.com/wp-content/uploads/2024/01/chris-king-microspline-freehub-2.jpg)
Available in Black or Silver, they’re compatible with all Center Lock R45D versions. They’ll also fit 2nd generation 6-bolt hubs with serial numbers starting with 6910. They fit Shimano’s mountain bike cassettes, which can be mixed with the new 12-speed GRX gravel components to create a wider-range 1x drivetrain on gravel bikes.
![chris king micro spline freehub bodies](https://bikerumor.com/wp-content/uploads/2024/01/chris-king-microspline-freehub-3-scaled.jpg)
Existing Chris King hub owners can retrofit with the complete axle-and-freehub body combo for $250 with stainless steel bearings or $310 with ceramic bearings. 12×142 thru axles only.