The most recent batch of rear 1990-1997 Mazda Miata Bilstein HDs are crimped under the rod guide. This means you can't easily take this kind of crimped damper apart to revalve it. My sources at Bilstein suggest this is a limited duration production change (although it affects several hundred dampers). So what do we do in the meantime, those of us who love and want to use Bilsteins for our Miata builds, whether street, track, or racing?
The changes I discuss in this and the next two videos don't apply to SCCA Spec Miata racing where a non-modified shock is mandated. In the near future, Spec Miata dampers and shock mounts will be provided by Penske - another video about this is coming up.
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In this first video I present the situation and offer some ideas as to how I would prepare this crimped rear Bilstein HD for machining to remove the crimped upper section which effectively shortens the body length about 0.80 inch (or roughly 20.5 mm).
In the following two videos, I'll discuss considerations for using alternate Bilsteins to get as close to OE body length as possible with less concern about reduced droop travel.