The factory rubber rear upper shock mount for the 86 / GR / VA chassis has a big rubber bushing inside a stamped steel mount. They wear out over time, can dry crack, even come apart completely. The worst part is - even when these mounts are new they have a lot of slop and "slow down" damper reactions to vertical inputs in the shocks. We can fix all of that.
Vorshlag has been making spherical shock mounts for nearly two decades for a variety of chassis: BMW, Corvette, Miata, 86 and more. These mounts specifically for the the Subaru GR/GV and 86 chassis are made in house here at Vorshlag and feature our oversized spherical bearing you'll find in our camber plates. These shock mounts are big, beefy, and as strong as a tank. Removing the stock rubber top mounts and replacing them with spherical top mounts will improve suspension articulation and movement.
We have drop-down options for known shock stem profiles. We can also configure our rear shock mounts for virtually any coilover damper, with some information you provide. Please see the sections below to help us build your set properly for a noise-free, perfect fit. We can also supply (as an option) Vorshlag radial bearing upper spring perches in 2.25", 60mm or 2.5" ID coilover springs - allowing the springs to rotate as they compress.
UPPER STEM DIAMETER: These shock mounts are designed to work with virtually any rear shock that is made for the BRZ/FRS. 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. YOU have to tell us how to build your shock mount assembly by picking the proper upper stem diameter of your rear shocks at the drop down menu below.
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 shock mount 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.
There are two methods of installing Vorshlag spherical shock mounts with your aftermarket coilovers - by using with the coilover kit's upper perch -or- with the Vorshlag radial bearing upper perch option below.
Radial Bearing Spring Perch: Most coilover rear shock sets come with a new upper spring perch to fit the included coilover springs. These rear shock mounts can work with those, but as an option, Vorshlag's spherical upper shock mounts can be configured with a spring perch complete with radial bearings and all appropriate spools or spacers needed to match your suspension.
Very similar to our camber plates, the spring perches help in eliminating spring bind. Many people will try and use thin Torrington bearings above their springs, but they are just not up to the task of street driving, never mind hard core track use. Rain and grit will muck up those flat bearings in no time - but our sealed radial bearings in these optional upper spring perches are good for many years of use.
Please Note: These shock mounts will NOT work with the springs that come with the Bilstein PSS10 Kit, or other coilovers that come with OEM sized rear springs. These shock mounts will work with the three most common coilover sized springs, 60mm, 2.25", or 2.5". Make sure during check out, you note the size needed to match your springs!