A little about me first.

I'm 6'2" 180lbs, 34-36in waist.

I'm purchasing a rollbar soon, and I cannot decide between getting the HDHCDD or the hardtop version. I don't have a hardtop, and even if I did I would use permanent locking plates so it isn't an issue. My reason for being on the fence about it is because I like the fact that the regular version is taller (I think it would look goofy having my head above the bar), but I don't want to whack my head on it from it being too close, even though I am getting the padding for whatever bar I get. I currently sit about 2 clicks from all the way back, and fairly upright in the stock seats so I'm really not worried about the seat interfering, just my head.

Also looking into a fairly cheap seat for the drivers side only. Something ~$400 or less, including mounting. Are the Kirky aluminum seats really comfortable enough to DD? I was also looking at the sidemount start, or a memoryfab S63. Really open to options here.

All this is going into my NB, but if it fits/works in an NA I cannot imagine it being much different.

 

I bought my Momo Start from a guy that was 6'1 or something like that. He said he bought the spec miata mounts for it (not sure which ones he's referring to or how low they are) and it was too tall for him. He went to a Kirky aluminum seat and mounted it to the floor and it was great, although not as comfortable. I wouldn't say that my Start is daily drivable, but some would argue against that, I do have a 52 mile round trip commute Mon-Fri.

 

one thing to really thing about as far as your choice of bars goes is how tall your race seat will end up.

The reason I say this is I have a HDHCDD in my car right now and have a Cobra Sukuzi(sp) race seat mounted to the stock slider. On the stock sliders the top of the race seat is just as tall as the bar. I can't use the very back clicks of the slider due to the seat hitting the bar. Now if I had a lower slider or just bolted the seat to the floor I won't have that problem but then I would have to massage the tranny tunnel to allow the seat to move more to the right to clear the door padding.

Also as everyone will say...if you can really try and test sit in some seat. If you really able try to find someone that has them and either driver their car or seat passager for a short trip and see how they feel.

I been in a kirky aluminum seat and was shocked at how comfortable the seat were. I don't think I would want them in my DD but I would see having them in my second car and be willing to drive long drives to events. Without being ungodly uncomfortable.

 

I'm a similar size, 6'3" 200 lbs 36" waist. I have the hardtop version of the bar, and Kirkey seats bolted to the floor, with the rear seat mounting humps amputated to get the seat as low as possible. My helmet clears the bar no problem.

I went with the hardtop bar because I knew I'd eventually get a hardtop. I swap the stock seats back in if it will be a while between track/autox events, and for street use I'm more comfortable with having the bar sit a little farther back even if it sacrifices a tad of height. If I recline the seats to lay back a bit, my bare head is still under the bar with stock seats. A mild foamectomy would give me a little more room for comfort and is something I'll probably do.

The comfort of my Kirkeys (intermediate road race) is pretty good for stints up to about 90 minutes, so they are fine for my DD use. The large side bolsters make ingress/egress a bit awkward with the top up or the hardtop on, but you deal with it. With the top down it's no problem since you can drop more or less straight down into the seat. A comfort problem shows up around the 90 minute mark for me. Where the seat back meets the bottom, there is an angled piece that my tailbone rests on, and it will start to hurt. Stuffing a towel in the lower back region to get my tailbone off that plate alleviates the problem. This is only an issue for me on longer trips, and I never even notice it in daily driving or track sessions.

Keep in mind that aluminum seats require back braces (I use the I/O Port ones).

 

Scott, do you have any pictures of your Kirkey seats?

I will be bolting whatever seat I get to the floor, as I am the only person that usually drives the car, and any one of my friends that drive it are about the same size as me.

The stock seats have a mild foamectmy now, and I will probably go with the HT version as I do not want the bar near my head while driving every day.

 

This is the passenger floor area showing one of the cut off humps. Don't know if NBs have them, but an angle grinder works well for removal. This will necessitate drilling some new holes through the floor for the rear seat mounting points, and for the sub straps. Not a big deal, just watch out so you don't damage any of the hard lines under the car in the process. You can also see the shorter pieces of bar stock that have been bent & drilled to adapt the Kirkey to the stock front mounting holes.


I don't have any closeup pics of the I/O Port back braces, but it's pretty obvious how to install them once they are sitting in front of you. Bolt the bracket around the Hard Dog's harness bar, drill & bolt the plate to the back of the seat, cut the bar to the proper length, and that's about it.

 

Dang, that actually looks REALLY good.

1000 thanks!

EDIT:

What width are those?

 

They are 16". My waist is 35-36" and the width is about perfect for me- snug & supportive on track and not so tight that it's uncomfortable for DD. I tried on other size seats at the race shop and the 15" was way too tight, and a 17" had too much extra room. The 16" is a pretty snug fit for the Miata as well. If one needed a 17" seat it would be doable I think, but it would be a real shoehorn job getting it in there.

 

I have the hardtop version of the HDHCDD, with padding. I am of a similar size, 6'2" 180 with 34" inseam. my seating position is all the way back. I had no issues with tech inspection at my first track day a couople of weeks ago with the hardtop on.

I've got the stock leather seats with a foamectomy. I didn't notice any issues on the track with the helmet hitting either the bar or the hardtop during spirited driving.

I think I would pass a broomstick test withoutt the top on, but haven't had a chance to try that yet (still raining here in the NW, so I've left it on).

The non-hardtop HDHCDD is a couple of inches taller, however, it will bring the main hoop a couple of inches farther forward as well. That was a dealbreaker for me since there's no way I would ever fit completely under it, so I have to stay in front of it.

 

I bought the Boss Frog Hardtop Clearview roll bar. The pics show the clearance from the stock seats for reference. Watch out for the rear window, some roll bars interfere with the glass rear window when the top is lowered.







Deft Racing had the cheapest prices for them when I bought mine.
Boss Frog Miata Parts