Chris King has always been about making the most precise components – it’s right there in the name. Their hubs are works of art, with their patented RingDrive system buzzing away as you coast. But that RingDrive precision came at a cost, namely a more complex service procedure and costly driveshell replacements.
Chris King had already phased out their needle-bearing design of the RingDrive system in 2019. Moving from that to a twin-bearing system reduced drag by more than 20% and made for a system that was lighter and easier to manufacture. The issue was that adapting the current hub design to the current twin-bearing system required multiple axle and internal driver body variations.
Now with the Gen 4 hubs, that all changes.
“Previous iterations of our hubs needed to balance compatibility with evolving external technologies, like the SRAM and Shimano drive systems, with our patented internals and bearings. With those core systems having stabilized, it gave us an opportunity to rethink what was going on inside our hubs, and so we took the chance to simplify things for our riders and streamline manufacturing.
For Gen 4 we undertook a holistic development process for each of the three hub products Boost CenterLock/6-Bolt, R45D, and R45, collapsing the specs into a design that allows for a universal axle and internal parts. In previous generations, we chased specs that led us to different bearing sizes, etc. Gen 4’s universal parts have allowed us to streamline manufacturing, and as a result, helped us reduce hub prices AND the cost of the small parts long-term riders will want for hub service and upgrades.”
King Sales Manager Greg Hudson
Notably, Chris King points out that “this is not a performance-based evolution.” Essentially, the hubs now use universal parts which allow King to offer drive system conversion kits for just $80 (for hubs that are already converted to or sold as Gen 4). Compare that to their previous conversion kits which were up to $380 in 2023. Better yet, the Gen 4 system is backward compatible with previous King hubs, so you can convert your existing hub to Gen 4 – though these conversion kits are more expensive. “Moving forward, Gen 4 R45D and Boost 6-Bolt conversion kits are priced at $275, which includes the axle, adjusting clamp, bearings, and driveshell. Similarly, Boost CenterLock conversion kits are priced at $250, inclusive of the axle, bearings, and driveshell.”
At the time of writing, prices for new Gen 4 hubs weren’t available, though we know that driveshell conversion kits for new hubs should run $80 since you only need to change out the driveshell. Chris King says that Gen 4 hubs are now shipping and are being built into their complete wheels.
Specific improvements with Gen 4 include:
- Brand new driver/axle system
- Improved compatibility/ease of changing Driveshell types
- Lower-priced conversion kits
- Better XDR user experience with threaded Driveshell end cap
- Easier assembly and disassembly (no axle wedge)
- Simpler preload adjustment (no spacer spring to compress)
- More versatility due to universal axle and internal parts
- More cross-compatibility due to common bearing sizes
- Backward compatibility with previous generations of King hubs
- Gen 4 R45D hubs utilize an updated adjusting clamp that allows for disc removal without the need to remove the adjusting clamp.
