The new Penske shocks are now shipping to Spec Miata competitors across the country. That means drivers will have to retrofit their old Bilstein setups. This feature will detail how the shocks go together. This is a new build, not a retrofit, but the steps are largely the same.
It’s probably a good idea to have a lot of space on your work bench for putting them together, the cleaner the better. The new handmade Penskes are such a remarkable step up from mass-produced Bilsteins that you won’t want to get them dirty before you put them on the car.
A couple of words of warning. The upper shock mounts need to be drilled out to 15/16 inch accommodate the new hardware. The mounts are made of thick steel, which is hard on drill bits and the user. We took ours to a machine shop and had them done on a milling machine. You can see a short video of that process here. It made it much easier and more precise, and was well worth the money we spent to have it done.
Machining Spec Miata Top Hats on a Milling Machine
If you’re building a new car, note that neither the new shocks nor the springs come with the rubber isolators pictured in the assembly instructions. You can get them separately from 5XRacing.com. Before you begin assembling the shocks and mounts, glue the isolators in place and allow them to dry.
The assembly process is pretty straightforward. The quality of the new shocks actually make it fun. Here’s a quick rundown of how they go together.