zagato78 New Reader
May 18, 2012 10:41 p.m.

I'm a Miata owner!! First time Ive owned much less driven one. Its a 90, more or less bone stock car. Runs and drives ok, smelling an exhaust leak and hearing some worn pads on the rears. Other than that, its my start for a Rallycross and Solo car.

Given other obligations, its going to a be budget minded toy for flinging around and having some fun. I do have a question about roll bars. For those of you who Solo with a Miata, what roll bars do you like? Or are the prefab ones just a waste of time?

thanks! Z

David S. Wallens Editorial Director
May 18, 2012 11:29 p.m.

Congrats on the purchase.

Duke PowerDork
May 18, 2012 11:58 p.m.

If you mean Solo II as in autocross, it's not required at all and adds weight up high. If you mean Solo as in TT etc, then the Hard Dog Hard Core Hard Top Dual Diagonal is popular, but not the only choice. It's a pretty darn rugged piece, though.

And as David says, congratulations! Miatae are fun in any form, unless you're a horsepower junkie. And even then they're fun, it just costs more.

EvanB UltraDork
May 19, 2012 12:38 a.m.

Miata? Rallycross? Now that is what I like to hear!

I have the Hard Dog roll bar, HDHCHTSD to be exact.

Just get out there and have some fun.

jrw1621 PowerDork
May 19, 2012 6:45 a.m.
zagato78 wrote: I do have a question about roll bars. For those of you who Solo with a Miata, what roll bars do you like? Or are the prefab ones just a waste of time?

Trying to read into your question, I have the following...
In the Miata world there are RollBars and there are StyleBars and they can both be often bought from the same company.
A style bar is more of an appearance items rather than a structural item. These may be the units you are referring to as a waste of time?
A roll bar is structural and meets racing requirements.

A popular company is Hard Dog (HD)
HD makes the Sport line which is good but not SCCA compliant for Solo 1 or typical wheel to wheel racing.

HD also makes the Hard Core (HC) line which is SCCA compliant.
The HD HC bars are made to fit with a hardtop (HT) or not and can have a single diagonal (SD) or dual diagonal (DD) pattern.
This is why EvanB referenced he has a HD-HC-HT-SD.

The Duece is a model from HD that is purely StyleBar:

Now with all that said, there is the difference between Solo 1 and Solo 2.
Solo 1 (often call Hillclimbs) is typically a higher speed event with compliant roll bars required.
Solo 2 (often called autocrossing) is a low speed event rarely getting into 3rd gear and a compliant roll bar is not required. The only reason a compliant roll bar would be required in Solo 2 is if you wish to use upper body restraint. An upper body restraint is anything other than a factory seat belt. Examples could be a 4 point harness or a torso belt.
If using this upper body restraint then not only must there be a compliant roll bar BUT ALSO the driver's helmet must be no taller than the bar.
Follow this logic...
If you have on the factory seat belt and in the rare event the car is flipped, the retraction function of the seatbelt would in theory allow the driver to lean forward to lower his head below the windshield frame or to the side to seek protection.
If you are using upper body restraint, the driver is essentially strapped into an upright position. Should the vehicle flip, he can not duck or squat. His only protection will be a roll bar and if his head sticks above the roll bar then that is like having no protection at all.

For me, at 6'1" I can not keep my helmeted head low enough to remain under a roll bar in my '90 Miata and therefore have never put a roll bar on which I run in stock class of Solo 2 - autocross.
This height test is often called the broom stick test. From the roll bar to the windscreen frame, a broom stick is layed and the driver's head must not hit the broomstick (clearance.)
Others solve this height issue by removing seat foam to lower the driver. This is often called a foamectomy.

As a footnote, I do not know what the roll bar requirements are for Rallycross.

zagato78 New Reader
May 19, 2012 8:31 a.m.

Excellent info gents. Thank you. My thoughts on the rollbar are more for my peace of mind rather than a specific rule set. The style bars are what i want to avoid. Auto crossing and rallycross are the extent of my ambitions with this car. I am 6'1 as well and anything more aggressive for me will require a bigger car.

Now to find a hardtop.....

jrw1621 PowerDork
May 19, 2012 10:02 a.m.
zagato78 wrote: Now to find a hardtop.....

Not all roll bars will fit under a hard top. You will see that HD sells two version, a taller one that only works with soft top and a shorter one that works with hardtops.

A hardtop is not required for autocross. I do not know for rallycross.

At 6'1" you will most likely need to make seat modifications to fit a helmet under a hard top.

zagato78 New Reader
May 19, 2012 11:42 a.m.

The drivers seat has had a fomectomy, the po was 6'3. I may get a bit more radical with it. Took it for a spin this morning, I've forgotten how much fun small cars are. Reminds me of my Fiats for back in the day...only with more power.

EvanB UltraDork
May 19, 2012 12:05 p.m.

A (factory) hardtop is required for rallycross. Both Hard Dog bars will fit under the hardtop but the regular (non-hardtop) version will interfere with the side latches on the hardtop. This can be solved by using bolt-on plates instead of latches for the side.

The easiest way to do it is to get the hardtop version though.

zagato78 New Reader
May 20, 2012 10:39 a.m.

One more question, after searching here and some other miata resources, topshock mounts when switching to bilstein hds. Using just the fronts as my example. F4-b46-1488-h1. Came from a 95 autocross car.

Since 95 is NB, to get the extra travel and bit of lift, I need a set of NB springs and a top mount set like the FM na to nb conversion. Do I have this right? Thanks

zagato78 New Reader
May 20, 2012 9:54 p.m.

NM, answered my own question.

EvanB UltraDork
May 20, 2012 10:01 p.m.

95 is NA if that was the question.

zagato78 New Reader
May 21, 2012 12:27 a.m.

Exactly. Trying to catch up on 22 years of cars a bit too quickly.

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