No they are not adjustable.
They are Gen 1 Wheel bearings as opposed to the Gen 3 hub and bearing fitted to the S2 and beyond Aero so are replaceable at limited expense.
FYI
GEN 0 Wheel Bearing
pair of taper roller bearings, as Trad front stub axles
Gen 1 Wheel Bearing
Large diameter double row Ball bearing
Gen 2 Wheel bearing
Large diameter wheel bearing with Drive flange
Gen 3 Wheel bearing
Large diameter double row ball bearing in carrier, combined with hub assembly
http://www.skf.com/us/products/vehicle-a...kits/index.htmlSimon @ SiFab.co.uk