BB30 frames use bearings with a 30mm inner diameter, which works perfectly with cranksets designed around 30mm spindles. The problem shows up when you want to run Shimano—HollowTech II cranks use a 24mm spindle that rattles around inside those larger bearings without an interface to bridge the gap. The BB30 to Shimano Adapter from Wheels Manufacturing fills that 6mm diameter difference, letting you install 24mm spindle cranksets in frames built around the BB30 standard.

Wheels Manufacturing machines these adapters from engineering-grade Delrin, a material that handles the compression and rotational forces at the bearing interface without deforming over time. Delrin also self-lubricates against the bearing's inner race, reducing friction as the spindle rotates. The adapters press into the inner diameter of the 6806 bearings that sit in your BB30 shell, creating a snug fit that centers the smaller spindle without introducing play. Installation requires nothing more than tapping the adapters into place with a soft mallet—no special tools, no press fits, no threading.

Once the adapters are seated in both bearings, the crankset installs normally. Slide the drive-side arm through, engage the spindle with both adapters, and bolt on the non-drive arm. If the crank has lateral play after installation, crank spindle spacers take up the slack and let you fine-tune chainline position. Wheels Manufacturing sells spacer kits separately in various thicknesses for this purpose. The combination of adapters and spacers means you can dial in chainline precisely rather than accepting whatever the stock configuration delivers.... Read More