When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
1mm, 2mm, 3mm, and 7mm - seems there is no exact formula for how many MMs of shim = x degrees of camber. Depends on your particular car and how they do it so you need a variety for the aligner to play with.
Gert is great. I ordered sets of the 2 mm and 3 mm shims from him and they came a day early, at a time when I really needed them to be on time. GT2's and GT3's come with 1 mm shims, so having additional 2 mm and 3 mm shims gives you the ability to have anywhere from 1 to 6 mm on each side, which should be enough to get at least 2.5 degrees negative if desired.