HDHCDDRB

Thanks for the help, everybody! I like the write up!

Here's the view from behind:

thatsnowinnebago wrote:

MCarp22 wrote:

thatsnowinnebago wrote: Oh and I run a hard top with it now, I just removed the side latches.

Which bar?

The HDHCDD

Ah, so the interference is not from the bar height but the side latches? I could live with that.

Keith wrote: Gratuitous plug: Mazda MX-5 Performance Projects by Keith Tanner includes a roll bar install

Alright, Keith! I bought your damned book!

And I bought your stupid roll bar.

I got the Hard Core Dual Diagonal bar. The one that won't fit the hard top. It was the M2, right?

Soon to be for sale: a Hard Dog single bolt-in bar.

confuZion3 wrote: And I bought your stupid roll bar. I got the Hard Core Dual Diagonal bar. The one that won't fit the hard top. It was the M2, right?

Yaay! :)

The M2 part only matters if you're going to use a glass-window top. Otherwise you might prefer the M1 version, as it comes with a harness bar instead of eyebolt tabs. Let me know at keith@flyinmiata.com or 800 359 6957. I can intercept the order and change the bar if need be.

If your current setup is just the single hoop with no bracing to the rear, it's called a Hard Bar. The Sport bar is just a Hard Bar with rear bracing, it wouldn't be hard for a GRMer to weld those one for a budget upgrade. I'll bet Hard Dog would even sell the bars ready to weld in.

Keith wrote: The M2 part only matters if you're going to use a glass-window top. Otherwise you might prefer the M1 version, as it comes with a harness bar instead of eyebolt tabs.

I've heard of some organizations not allowing harnesses attached to tabs. The OP should probably double check with whomever they run with to be sure the tabs will be acceptable (assuming he's going to install harnesses).

Edited: Yeah, an e-mail is being sent out now . . .

Thanks again guys. You have saved me from a stupidish mistake.

Do rear mounted roll bars add significant structural rigidity to the car?

S'ok, the issue of a shared mounting point for the shoulder harnesses only became an issue after the M2 bars had been on the market for about 6 years. Most places don't care - but it's even easier to simply sidestep the issue.

Yes, the bar will add noticeable structural rigidity.

I've got the DDHT bar and can't run the seat all the way back or recline it much without resting my helmet against the pad. This is the defining issue with mounting a race seat, as it limits the mounting angle. Move it forward and your knees come up in a go kart position, move it back and lose leg support as the base goes more horizontal. Keep this in mind when choosing a seat. I missed on the first try but found a pretty comfortable combination the 2nd time around.

If you're going to a roll bar you're probably going to the track. I find the chassis of the NA to be a wet noodle without a cage, and have little confidence in stock form. So I just finished installing belts and suspenders. Noticable reduction in cowl shake on the street, real test (first track day) is next week.

http://www.flyinmiata.com/index.php?deptid=4538&parentid=0&stocknumber=13-69920%20%201990-97

http://www.bethania-garage.com/door_bar.htm

I think that first link was supposed to be http://www.flyinmiata.com/index.php?deptid=4538&parentid=0&stocknumber=13-69920

Dashpot wrote: Keep this in mind when choosing a seat. I missed on the first try but found a pretty comfortable combination the 2nd time around.

Sorry for the thread hijack, but Dashpot, what seat and rails did you end up using?

Woody wrote: Sorry for the thread hijack, but Dashpot, what seat and rails did you end up using?

I used a Racetech 4009W. Not a budget decision, but I got a decent deal on a leftover. I sat in Cobra's and Recaro's but chose the Racetech for comfort. It's a very sturdy seat. I hope this link works:

http://www.racetechseatsna.com/race_seats/RT4009.html

No rails, through-bolted with backup plates. I used a 1/4" x 1" full width aluminum shim on the front seat crossmember, with the front seat base flange backed right up against the crossmember for a nice fit. Drilled through the cross member and floor, 5/16 x 4" high grade (8.8 or better) bolts and 4x4"x1/8" backup plates underneath. The back corners are bolted through the floor with backup plates as well. The top of the seat clears the thick SFI roll bar padding by better than a 1/2", so helmet clears it too. I had to relieve the vertical seat flange where the right side thigh support butts up against the tranny tunnel, and took a nip off where the door bar contacts it on the left. The shoulder wing clears O.K. too. Let me know if you want me to e-mail you some pictures.

For reference, the old seat was a Corbeau Forza. The seat base came up short of the cross member and there was pretty much zero thigh support in that configuration. O.K. for the track, but kind of a drag on the way up there & back. If anybody's interested, it's a black microsuede with lumbar....

In my experience, the first thing to do with Corbeau Forzas is to pull the seat cushion and replace it with memory foam. Puts you lower in the seat and improves thigh support and comfort.

MCarp22 wrote:

thatsnowinnebago wrote:

MCarp22 wrote:

thatsnowinnebago wrote: Oh and I run a hard top with it now, I just removed the side latches.

Which bar?

The HDHCDD

Ah, so the interference is not from the bar height but the side latches? I could live with that.

Correct, although the padding on mine does squeak a little sometimes against the underside of the top