This Chris King external cup bottom bracket is specifically designed to be used with SRAM and TruVativ GPX style cranksets. GXP crank axles that fit into the external cups are similar to Shimano, except they have a 'stepped' axle, meaning, the axles on the drive side is 24mm and then tapers to a 22mm on the non-drive side. The idea behind the design is to transfer some of the load and force to the drive side of the crank/bottom bracket area.
Instead of offering 2 sizes of bearings, the engineers at Chris King offers 2 -24mm bearings with an axle-shim system comprised of a washer and 2 spacers to make the non-drive side 22mm. We have found that this feature works flawlessly and installs and sets up with ease. No surprise either - Chris King requires a true priori knowledge of a product which comes from exhaustive research and testing before they are available to the general public. It also explains why a Chris King product rarely changes after its initial product launch.
In terms of the raw product, the cups are machined and anodized to surgical precision. Bearings are as high quality as you can get and are also serviceable with Chris King's bearing lubrication tool. Full kit includes both cups, GXP shim kit and center sleeve. Choose your color.
These BB's are compatible with SRAM and Truvativ GXP cranksets only and will not work with Shimano or FSA cranksets.
I have used this bottom bracket for about one full season - I replaced a Sram ceramic unit that was worn after about 1.5 seasons of use. It actually spins better and would say the overall quality of the cups are far superior to the Sram unit. Unlike the other reviewer, I had no problems with any creaking or squeaking. Installation with the axle shims was dead simple. It has been quiet and not had any issues at all. Highly Recommended.
I was very hopeful that this BB would prove to be reliable and trouble free. Unfortunately, I think it has a fundamental design flaw. SRAM GXP crank spindles have two different diameters for the drive and non-drive side. The SRAM GXP BBs have bearings with reduced inner diameters on the non-drive side to match this design. The CK SRAM BB design uses a system of sleeves/shims and spacers to get things to fit and line up right. So, rather than design the inside diameter of the non-drive side bearing to match the OD of the corresponding spindle, they supply a sleeve to fit over the spindle. Well, guess what? That sleeve creaks. It creaks no matter what you do, no matter how much grease you apply, and theres really no way to secure that sleeve. A creaking BB drives me nuts, so I gave up on this BB after 500 miles and 4 attempts at eliminating it. The good thing is, since its really just a shimano BB with spacers, I can use it for a shimano/fsa crank later on.