Strut Tower Braces

I'm about to start looking at fabbing up some chassis braces for my Miata and I was looking at different designs. I notice a lot of them have a joint at each end with a rod end usually.

My question is that it looks like the ones that are jointed are the easiest to fab however it looks like that joint would simply move under a load making the brace do nothing at all.

The one that looks the most stable is the one that runs from each strut tower to the firewall but at the same time also the most difficult to fabricate.

Thanks for any help on pointing me in the right direction

For home built stuff an adjustable joint (threaded Heim) at each mounting point will save you a TON of headache by allowing you to fine-tune out that 10th of an inch you screwed up, as almost always happens.

It also lets you dial in some tension on the brace, if you want to do that.

If the mounting point is properly triangulated it won't move.

You could also look into adding a master cylinder brace. Some people love them, some don't notice them.

Oh, one thing about the threaded heim joints:

For the cross-car brace (suspension to suspension) get one normal threaded rod end and one counter threaded. This will make width MUCH easier to adjust, and make adding and removing tension cake.

In essence, rotating the bar one way would widen it, turning it the other would narrow it.

Also, look at welding a larger nut onto the brace in 1-2 spots so you can use a wrench to turn the bar. Way easier than doing it by hand.

Make sure to use a lock nut (non-welded nut) on each side to prevent the bar from slowly loosening if you do go this route.

all the strut to strut designs I've seen have a bent bar. To me it looks almost impossible to rotate the bar unless you remove it from the car first. Unless you made the mounts on the strut ends high enough to use a straight piece of bar from one side to the other.

Mazdaspeed factory bar is straight across, so it is doable.

does the miata need a strut bar? it looks to me that the structure of the engine bay is enough...

My 2003 came with a nice straight bar. You should look at the later model NBs to see how they are designed.

When I added a STB to my NA it did help... not a lot, but did help. What helped stiffen things up tremendously was the roll bar. I could not believe what a difference that made!

RJ

This car had a lot of stuff installed before I got it but I didn't notice until I started to look further into the car that things had been installed them removed before being sold.

The rear deck area has been cutout for a rollbar so I assume it used to have one as well as a seat belt tower brace. The plastic where it mounts has been cut out. I do plan on a roll cage in the near future but need one that won't make the car undriveable on the street or make the top useless.