rallyxPOS13 GRM+ Memberand New Reader
2/11/22 5:19 p.m.

I'm working on adding some travel to some DIY rear coilovers for my RallyCross 240SX.

In my build thread, ¯\_(ツ)_/¯ had the fantastic suggestion to look at other cars that may have less stupid top hat designs that allow a smidge more travel at the end of compression.  Since Miata is always the answer, I recall the NA folks swapping NB top hats in for this reason.

Does anyone have a Miata rear top hat kicking around to grab a couple measurements?

I'm aiming for something with stud spacing somewhere around ~81mm or 3.2"

And the central hole is coming in around 48mm or 1.9"


Thanks in advance!

EvanB GRM+ Memberand MegaDork
2/11/22 5:34 p.m.

I posted in the build thread before I saw this. The Miata is around 5". 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
2/11/22 5:52 p.m.

Stud location can be changed in the hats, too. The studs just press in like wheel studs.  So, all you really need to be concerned with is the ID of the chassis' shock tower.  (General ID, not center hole)

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
2/11/22 6:08 p.m.

The NA folks have some bad info about that, but that's a different story :)

If the goal is to move the top shock mounting point up, the easy answer might be to modify your existing upper mounts. Get some exhaust pipe big enough to go over the shock body (say, 2" or 2.25"). Use a hole saw to drill a matching hole in the top of the mount. Weld back together using the pipe as a spacer. Voila.

moxnix Dork
2/11/22 8:05 p.m.

If you should decide you want to lay hands on some to play around with I know I have some NA ones and might have some NB ones in Woodbridge.

CollectingJunk New Reader
2/12/22 7:44 a.m.

Excuse the messy workbench, but here's a few measurements on a set of NB tophats.


Stud to stud is 119mm.


Center section is 53mm.

Hopefully that helps!

fusion66 Reader
2/12/22 7:54 a.m.



What Keith said - I moved the shock "down" to raise the car but the inverse could certainly be done as well. The three pieces on the right could do that. 


Final product on the left


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