Roll Bar - HDHC versus HDHC 'Hardtop'
 

As established in this thread (thanks Y8S) BOTH the regular M2 Hard Dog Hard Core (HC) and M2 Hard Dog Hard Core Hard Top (HCHT) WILL fit in a NB with a hard top, even with padding, despite what Bethania says.

So I am about to get one of these, and am wondering about differences between the two versions. Here is what I think is going on. Tell me if I am right.

The M2 HC hoop sits slightly farther forward in the car. The M2 HCHT sits farther back.
The M2 HC is slightly taller than the M2 HCHT maybe 1.5"?
The M2 HC covers up the side hard top latches. The M2 HCHT does not.
The front attachment points on both versions attach to the same points on the chassis. I am not sure about this one.
The seat belt retractors might work a little better with the M2 HCHT?

So it seems like the main reason to go with the regular M2 HC is for the additional head clearance. When using a hard top, one can either go without the side latches or get a solution like those shown in the aforementioned thread. Correct? Anything else to add?

You got everything basically.

The main different between the HardTop and HardCore bars is that the HT bar is angled backwards more to allow clearance for the stock side latches as where with a HC bar the bar is angle to run on top of the latches.(to the point I couldn't install the stock latch on without tapping it in with a hammer, lol)

Everything HT bar I have seen bolts to the same places in all four corners.

The other questions I don't have an answer for as I have not compared HT and HC uninstalled to compare height or compared if the seat belts function smoother.

Yea, youre onthe money.

My M2 HC non-HT version rubs my OEM hardtop. Enough that is has 1/8" depressions and I've wiped plenty of fiberglass dust off the tops of the seats and rollbar.

Mine also does not attach at the upper seat belt tower which allows the seat belts to retract better than any other HD bar I've owned M1HCDD,M1HCHTDD,M1HCHTSD,M1SportDD,M2SportDD

OK that right there would steer me towards the HCHT. Judging by your sig though, maybe since you have an M2 in an NA you are having clearance problems because the NA hard top is different (shorter) than the NB hard top?

WHAT? I was under the impression that there was no difference in the hardtops and that they were all interchangeable....

According to this the NA and NB hardtops are the same. So much for my theory.
http://www.miata.net/garage/hardtop

The difference in fits between Paul and Y8S then could be simple tolerance stacking. There are certainly several potential variables: the hardtop itself, the roll bar, latches, seals, and roll bar mounting.

I also prefer the positioning of the HT one purely for aesthetics, I like how it sits back a bit further and doesn't sit so high. Actually, one thing I noticed is the HT bar doesn't sit directly above your head, whereas the regular ones do sit alot closer, something you might want to consider just in case you have any accidents that would cause you to jump up in your seat and maybe bang your head. I know with my hard top one it's still higher than my head but just sits behind me a few inches so there's no need to worry about launching the top of my head into the underside.

You cannot use the acronym HT for a roll bar. Just doesn't work.

One other thing to keep in mind when deciding is your height. If you have a long torso a HD HT may not be suitable as your head might hit it. I know Chad went with a HD nonHT because his head was to close to it.

i've got clearance alll around my bar between it and the hard top.

maybe paul drilled his holes wrong :)

actually it could very well be tolerances. I doubt bethania holds +/- 1/8" on height. That could be enough that if I got a short bar and he got a tall bar there'd be some rubbing or not.

Yeah I agree I doubt they hold +/- 0.125".

Time for some engineering geekage. Say that based on my list there are five sources of tolerance stackup. Assuming all five sources are +/- 0.125", and using root-sum-square stacking, then it is reasonable to assume the overall effect could be +/- 0.28". If the errors are assumed to be +/- 0.2", then the overall stackup is +/- 0.45"

I'm leaning towards the M2 HCHT version. Plus there are a couple of big guys I know (over 6 feet) that ride in my car from time to time. With the stiffer springs and shocks the roof clearance alone can be an issue on big bumps. The other day one of them hit his head on the roof (seatbelt on) when I went over a bump on an on-ramp :giggle: So it seems like the rear tilt would help with that. I am getting padding regardless.

Now all I need to know is when Bethania is doing their next free shipping deal. ;)