As you’ve read by now, I’m running 2 sets of thru-axle wheels on the Spooky. One has Zipp hubs and the other has Chris King hubs.
The King hubs are about 0.5mm narrower than the Zipps at the location that your disc rotor installs. Both are perfectly true, but with that difference in width, if the rotors are installed directly on the hubs, you’d have to adjust the calipers every time you swap wheels. That would, in the technical parlance, suck.
The solution came after about 30 seconds of googling. Syntace makes 0.2mm disc rotor shims for 6 bolt discs. They come in a pack of 8, and are made of stainless steel…so they install behind the rotor and shim it over to where you need.
Since the Kings are narrower, I set up my brakes to work with the Zipp wheels and then shimmed the Kings to fit with that setup. In my case, it took 2 shims, front and rear, for perfect setup.
If your rotors are true, this means that you can swap wheels back and forth with no adjustment of the calipers, even if you have different brands of wheels with different width hubs. They’re cheap, easy to install, and work perfectly.
This is the shims, in the bag.
And here, you can see them installed on the King hubs, behind the rotors.