Multi-piston caliper upgrades require careful centering of the rotor with a fixed caliper position. In many cases the caliper can be shimmed toward the but not further away.

  This simple shim can be placed behind the rotor and wheel hub, moving the rotor away from the caliper as a simple solution for tight fitting calipers without compromising the hub-centric wheel fitment. 

  These Shims feature a 70mm center bore to fit snuggly on the rotor centering shoulder of most Saabs and related GM European cars with the same lug pattern.
  These are not intended to be used as wheel spacers and will provide challenges to align lug bolts if used as such.