Need input on this strut swap on my Miata

My car came with stock shocks and lowering springs (according to two previous owner's ago).

I was hitting the bumpstops pretty hard on one side in particular, so I picked up another set of stock struts off Craigslist and ordered a set of Honda 65 mm bumpstops:

Cut one ridge off for a 50mm bumpstop equivalent. I pulled one rear strut off and compared the old and new side by side (old on top, new on bottom):

This was not what I expected. I thought the new one would be longer, but it's the same length, with tighter coils. I went ahead and pulled off the spring, which was fairly compressed. Installed the bumpstop, and installed on the car. From jacking up the bottom of the A-arm, it was hard to tell whether it was hitting the bump stop first or the coils. The coils were not physically touching when the car began to raise up, so that may be a good sign.

When the right side was installed, the ride height was noticeably higher. Why it became longer while on the car, I have no idea.

Any input or advice before I install the remaining three?

Bumping this back up.

I guess I'm not sure what your question is.

You only mention buying "stock struts", but it looks like the springs are different too. Did you reuse the lowering springs with the new dampers?

calteg wrote: I guess I'm not sure what your question is. You only mention buying "stock struts", but it looks like the springs are different too. Did you reuse the lowering springs with the new dampers?

No I did not reuse the lowering springs. The strut on top are the ones I pulled off, those are supposedly lowering springs. The strut on bottom is the one I bought, with unknown spring. Does it look like the stock spring, or a longer aftermarket that someone made fit? I'm concerned about coil bind, but haven't gotten a chance to drive it hard enough to see if it does.

Seems like you answered your own question then.

more coils in the same area = higher spring rate = higher ride height. (assuming that the springs are the same thickness, etc)

The new ones you bought appear to be OEM, but it's tough to tell from one photo. Bottoming out the suspension is a fact of life with the Miata, hence why the bumpstops are an integral part of the suspension.

The bottom spring looks like a stock one to me.

calteg wrote: Seems like you answered your own question then. more coils in the same area = higher spring rate = higher ride height. (assuming that the springs are the same thickness, etc) The new ones you bought appear to be OEM, but it's tough to tell from one photo. Bottoming out the suspension is a fact of life with the Miata, hence why the bumpstops are an integral part of the suspension.

It was less an issue of hitting the bumpstops and more that the bumpstops were shot.

I think it finally clicked for me, thanks guys.

Swapping to NB tophats supposedly will give you a bit more suspension travel as well. You'll still hit the bumpstops though.

If I were you I'd get intimately familiar with the suspension sections of Miata.net or miataturbo.net. Figure out what your suspension goals are first, then proceed. You can cobble together a respectable suspension for a few hundred bucks.