[Miata] 01+ NB Drivers running FM Sways?

[Keith Tanner]

Okay, some facts for everyone :)

Oversize front sway bars have shown the capacity to rip the front sway
bar mounts off the frame on NBs. That's all 1999-05 cars. The large
size of the RB bar would certainly make it more prone to doing this
than a smaller one, such as the FM bar. Note that this is the frame
mount for the sway bar bracket, not the control arm mount for the end
link.

The mounting point on the control arm for the end link changed from a
double shear (U-shaped) bracket to a single shear (single tab) bracket
in 1999. No changes were made in 2001. The reason for the change was
to make it possible for Mazda to use a ball joint on the end links
instead of the rubber bushings used on the NA, which I think was a
good upgrade. While a single-shear mounting point is not as desirable
as a double-shear one from an engineering standpoint, Mazda did use
metal that was approximately 3 times as thick with the new tab. It's
very strong, and if you pull one free I would expect all sorts of
associated damage to the car. In the salvage cars we get here, I've
seen the end links pull apart but I've never seen damage to the
mounting point. It's probably worth noting that if you buy a new
control arm for your NA, Mazda will give you the NB version.

I'm not sure what "the bad batch" comment refers to, but as the NBs
age we're starting to see a few of those ball joints on the end links
come apart. After all, the 1999 models are 10 years old now. It's
still very rare though.

Back to my original comment in the thread - the 1999-00 and 2001-05
cars are the same from a suspension point of view.

If you want an FM front bar only, you should be able to find that by
either looking in the catalog (p 23) or in the Suspension part of the
webstore. It's not something that I'd recommend for good handling
unless you're running unusual rear spring rates, but it does seem to
be fashionable these days.

Keith