2012 Chris King campagnolo hub internals comparison to mountain bike hubs with ceramic bearings

With the introduction of Chris King’s Campagnolo-compatible freehub and ceramic bearings option a bit a go, it gave us a chance to look a bit deeper at the R45 road hubs and see what makes them different from King’s standard hubs.

The road hubs use a smaller setup with a 45-tooth ring drive, hence the model name R45. The change from their standard 72-tooth version was to reduce size so they could make the hub shell smaller. They also wanted to reduce the noise. But the big techie reason has to do with degrees of engagement differences between road bikes and mountain bikes.

“When we had to shrink everything for the R45, if we had wanted to put 72 teeth in there we’d have had to shrink the teeth. Our goal was to limit it to a half inch of pedal movement,” said Brian Schultz, product engineer. “With road gearing, 45 teeth ends up with 7.5º 8º of rotation, giving a maximum of half an inch of pedal movement with standard gearing.”

The bearings are built into the drive shell differently, too. On the MTB hubs, there’s a needle bearing in the center of the freehub body because it handles radial forces well (as in forces that are perpendicular to your axle…like dropping off a rock). That’s good for mountain biking and such, but they have a bit more drag.

“With the road hub we went with ball bearings because they have less drag,” Schultz said. “The slotted spring you see in between the two sealed bearings introduces preload for the bearings inside the freehub body. The preload takes out the play in the bearings since they’re angular contact sealed bearings, not radial, and can be adjusted as they wear in via the adjusting clamp on the exterior of the non-drive side.

“The Campy version differs from the standard R45 in that it uses two same-sized bearings in the freehub body because of the deeper splines. With the regular R45 hub, the outboard bearing is a bit larger because Shimano/SRAM freehub bodies don’t need such deep splines.”

The Campy’s axle is also slightly different to accommodate the smaller bearings, so if you were to switch from Shimano to Campy, you’d need to replace the axle and freehub body.

The mountain bike hubs (and all of their other hubs for that matter) use a 72-tooth ring drive engagement system and 19.5mm axle. The R45 hubs use a thinner 17mm axle.

Where the road hubs use a spring between between the two sealed bearings, the mountain bike hubs use a spacer with flared ends between the sealed bearing and needle bearing. On the outboard side, the Seal Ring threads in to compact it all and keep the angular bearings tight. The Seal Ring also incorporates a rubber mud seal to keep the crud out, hence the name.

The Road hubs all have a slightly thicker spoke flange with a bit more “meat” above the spoke holes to handle radial lacing, something that’s not recommended on their regular hubs, especially not for disc hubs.

2012 Chris King R45 Campagnolo road bike hubs closeup photo

Close up of the Campy freehub body. Them’s some deep splines.

2012 Chris King ceramic bearings upgrade for road hubs

A closeup look at their ceramic bearings.


  1. Dear Chris king, please make a mountain bike hub set based on the r45 design. 45poe is way more than some of the popular mtb hubs and would be perfect for racing. The weight savings would be welcomed too.

  2. Yeah, I’m with Cw. A lightweight “XC/CX/Road” hub based on this design with disc tabs of course, available in 135 and 130mm axle lengths. There’s a burgeoning cross and road market for this and the off-road weight weenies would rejoice.

  3. I’m willing to bet CK will come out with, if they’re not already working on it, a 130mm spaced rear hub for disk brakes. The road market isn’t exactly burgeoning yet, but it is creeping in a direction that could lead to burgeoning. Also remember, CK typically isn’t fast to market with products. After all it has taken a few weeks……ok, years……for them to bring out a Campy hub.

  4. Maxi, we don’t censor comments except for lewd profanity, irrelevant personal attacks or racial slurs.

    Perhaps you’re referring to your comment left on the original post about the hub’s introduction that might have been meant for here? If not, then we blame gremlins.

  5. Can we stop calling different widths and designs “new standards?” If the entire industry is not using a different design throughout, it is not a “new standard.” It is simply a new design.

  6. 130mm disc hubs seems kind of ridiculous. Stick to 135mm. What is the point, there is already a huge selection of 135mm hubs, why introduce another variable. It’s not like there was a huge selection of 130mm disc frames…why invent a new standard. I fail to see the real need for such a design.

  7. Agree that we should stick to 135mm spacing for disc hubs. However, there is a need to add a Campy option that is totally lacking in 135mm hubs at the moment. 130mm Campy disc hubs are already available.

  8. I agree with Robert and Tom, 135 is the way to go since mtn bikes have been using it for years without any issues. As usual, road bike standards sadly trail behind mtn bike innovations.

  9. The R45s are not durable at all. I’ve had mine for ~3 months and they develope excessive play every other ride. It’s really frustrating, especially b/c they were $$$.

    I’m at the point where the hub adjustment yields too much drag.

    Not a good product, IMO.

  10. @shift: That is not an uncommon complain for CK hubs. I have a mountain set that I’ve been happy with but it took me a long time of break in before I could get them adjusted properly to eliminate the play. I know lots of others (especially those heavier and harder on gear than I) who have complained about the bearing preload loosing up on their hubs repeatedly. I love the ring drive engagement system, but CK should work on the whole preload thing. Both sets of Hope hubs I’ve owned have none of this fiddly hex key preload crap, and I’ve yet to witness play in any of those hubs and that is after 3 hard seasons of racing.

    Perhaps there is some costly patent holding them back (like their headsets).

  11. Well, I’ve been running a set of turquoise Chris King non-disc hubs on my MTB for over 10 years and never,not once had an issue with them. Yeh, there’s a break in period for the bearings but that’s fully explained in the manual when you buy the hubs and after about 100 miles it’s just a simple adjustment and then you’re set! Easy.

    I also run Chris King Cyclocross hubs on my ‘Cross bike and they too are easy to live with. Had them two seasons now and not one problem.

What do you think?