Vorshlag RSMs use the largest spherical bearing on the market (19mm ID) – it is massive, which means it is strong. They use a U.S. made, Teflon lined, aircraft quality stainless spherical ball, stronger than the commercial grade import sphericals used in many competitors’ RSM designs. The spherical bearing location itself has been raised above the shock tower, to increase overall bump travel for your rear shocks.
Vorshlag has tested this design for 4+ years and they are silent, effective, and have no slop or bind in use. If you somehow manage wear out the massive spherical bearings in these shock mounts, they can rebuild them quickly and cost effectively at Vorshlag’s HQ in Texas.
UPPER STEM DIAMETER: These shock mounts are designed to work with virtually any rear shock that is made for the BMW models listed. We use different upper and lower bushings (spool pieces) to adapt the big 19mm ID of our spherical bearing to the shaft sizes of the very top of the rear shock.
Virtually all shocks made for these BMW chassis use a 14mm or 16mm diameter main shaft (and even some that are 22mm). The part we need to know from you is the very top – which will have a 10mm/M10 threaded or a 12mm/M12 threaded upper shaft stem. Typically an OEM or non-adjustable shock has a 10mm shaft and an adjustable aftermarket shock has a 12mm shaft. The RSM sits on the shoulder or step where it goes from the big diameter and necks down to the small upper stem diameter. See the images below for a better explanation. If you are unsure about shock shaft upper stem option to choose, please email or call us.
Vorshlag RSM Upper Reinforcement Plate Kit: We offer a pair of our laser cut reinforcement plates as an optional add-on for this shock mount kit with a package savings. These plates sit on top of the shock tower and help sandwich and strengthen the somewhat thin factory sheet metal, above and below. We CNC laser cut these from alloy steel and then zinc coat them. Our design is thicker and stronger than the factory (Z3) reinforcement plates and a smart move for any street or race car – to help prevent cracked shock towers.