A buddy and I were talking about the possibility of a roll bar in my daily driver Miata so I can rallyX it. He cautioned me that if I get rear ended on the street, the impact will force my body back and up, hitting the back of my head on the rollbar. Looking at a few Miatas with rollbars, I can see how that could happen.
Anyone have any experiences or advice?
I have ridden in one. At 6'2" my head is about 2" from the bar. A rear end collision would have busted my head like a watermelon. I won't ride in one again without a helmet.
Also, remember that rollbar padding is for your helmet, not your bare head!
I bought the ace for my street car. Furthest away from my head.
For my seating position, i would have broken my spine before hitting my head on the top of the main hoop. However, in a HARD t boning it was possible that i could have hit the leg of the main hoop.
It’s definitely something to consider. There’s just not much room in the car for both you and the bar. The further away from your head the bar is, the lower it has to be in order to clear the top. Bars like the Ace give good horizontal clearance but are considerably shorter and may not pass a tech inspection. The Hard Core is at the other end of the spectrum, giving maximum height but almost close enough to be a headrest. The Sport splits the difference. These are all Hard Dog models, but all bar manufacturers have to deal with the same trade offs regardless of marketing.
So basically, you have to decide where your priorities are: roll protection or rear end protection. In every case, getting yourself lower will make it easier. Also choosing not to be 6’3” will help, but most people don’t think that far in advance.
Also scca doesn't require a roll bar for rallyX, just an OEM hardtop.
I dunno, getting rear ended in any miata, with or without a rollbar probably isn't going to be great for your health.
I have one. I keep my seat at a non-optimal position so that I won't hit the rollbar. I'll be selling the car soon, and if/when I replace it with another Miata, it won't have a rollbar.
Being short, when I had my NA + Hard Dog Hard Core, with fixed backs and harnesses, I was low enough that if my head hit the bar, it meant my FIA seat failed and my head moved multiple inches after doing so.
I figured with that violent of an impact, it probably wouldn't matter if I had a roll bar or not.
Miata story: Someone pulled out in front of me once and I jinxed over so fast my head didn't keep up with my body. My head hit the the seat belt column hard enough to raise a welt.
If someone had actually hit the driver's side and the same thing happened, but with more force, I don't think I would have fared any better than a rear end collision scenario where my head hit the roll bar.
In theory the rollbar should likely prevent someone driving up over the back of the car & parking on your head/torso. That would be enough for me to strongly consider one(which I had, in my old/now mtn’s car), however I doubt I’ll put one in my current 90 due to weight vs. autox.
My Miatai that have had roll bars also had racing seats that lower my position several inches. I felt MUCH better about the roll bar with that setup.
My NC has so much more room that at 5'9" I actually have the seat a few notches forward of all-the-way-back.
My NB that I'm selling has a roll bar and racing seat. Haven't crash tested it, but I think my head won't reach the bar with the harness on.
My new car is autocross only. It's only going to be driven on the street until I can buy a trailer. Weight needs to be kept to a minimum, so no bar.
KyAllroad (Jeremy) said:My Miatai that have had roll bars also had racing seats that lower my position several inches. I felt MUCH better about the roll bar with that setup.
My NC has so much more room that at 5'9" I actually have the seat a few notches forward of all-the-way-back.
Word. I’m six feet tall with a long torso, and I wasn’t safely below the roll bar until I cut out the rear seat humps, fabbed up a floor mounted seat bracket, and installed a Kirkey seat. It can be done.
Have the Harddog M2 roll bar in my NB. Also have Corbeau FX1 Pro seats in the car. The top of the seat back is almost even with the top of the roll bar. Think the seat would act as a buffer, at least slow my head down enough to only rattle what is left between the ears.
I think you all have verified that with stock seats in a NA, a rollbar can split your melon in a rearend crash. I see a rearender as far more likely on the street than rollover. I see at least a couple incidents every week during my commute where two cars are pulled over...one with a crunched hatch and the other a bowed hood. So from that perspective, I'm better off without a rollbar for mostly street use.
Interesting that SCCA RallyX allows OEM hardtop rather than rollbar. Might have to look into that. They tend to be $1000-1500 around here, and you have to hope you aren't feeding the rampant hardtop theft market.
The best solution might be buying a fixed roof "something or other" just for thrashing on the RallyX course. The Miata is still in pretty good shape and I kinda hate to trash it doing RallyX.
Why not the treasure coast miata fiberglass hardtop shell? Its like 550 or so if i remember correctly
In reply to Dusterbd13-michael :
I just looked at SCCA rules...they allow non-OEM with a rollbar or roll cage in Modified, or "approved" hardtops (with no indication of what "approved" means) in other classes, and it ends up being at the discretion of the Safety Steward of the event.
Dusterbd13-michael said:Why not the treasure coast miata fiberglass hardtop shell? Its like 550 or so if i remember correctly
I don't know why you would use a Miata in a competitive environment with either without a roll bar.
OEM and TCM hard tops are NOT structural support in any way, shape, or form.
Not debating how safe a roll bar is without a helmet in a street car. However it would seem a properly built and installed roll bar would add some structural stability to the Miata body shell and prevent fold upon a rear collision. Don’t own a Miata but just asking.
I often wonder why so many Miata with rollbars have never heard about rollbar padding.
I have more experiance with this than I would like. Here is the thread of when I got rear ended with a roll bar.
https://grassrootsmotorsports.com/forum/grm/thank-you-hard-dog-and-bethania-garage/139251/page1/
While debatable, I believe the roll bar helped keep the occupancy cavity from collapsing. After the accident, neither door would open.
I did have a cut on the back of my head, but i think it was from the seat, not the roll bar. However, every roll bar of mine going forward will have padding.
AnthonyGS said:I often wonder why so many Miata with rollbars have never heard about rollbar padding.
Rollbar padding is for helmets, not your bare head. So it's not relevant in a street situation.
z31maniac said:AnthonyGS said:I often wonder why so many Miata with rollbars have never heard about rollbar padding.
Rollbar padding is for helmets, not your bare head. So it's not relevant in a street situation.
Seems like it would be better to hit your bare head on padding instead of a hard steel roll bar. It could make a difference in lower speed crashes, not as much if its a high speed hit. Maybe the answer is to put the regular padding on the roll bar and in the area your head could make contact put an eccentricity mounted layer of softer material rotated into a position so you can still close the top. Bottom line is a Miata is not as crash survival able as a larger vehicle. Better than a motorcycle. Worst than a Subaru.
jharry3 said:z31maniac said:AnthonyGS said:I often wonder why so many Miata with rollbars have never heard about rollbar padding.
Rollbar padding is for helmets, not your bare head. So it's not relevant in a street situation.
Seems like it would be better to hit your bare head on padding instead of a hard steel roll bar. It could make a difference in lower speed crashes, not as much if its a high speed hit. Maybe the answer is to put the regular padding on the roll bar and in the area your head could make contact put an eccentricity mounted layer of softer material rotated into a position so you can still close the top. Bottom line is a Miata is not as crash survival able as a larger vehicle. Better than a motorcycle. Worst than a Subaru.
Hard Dog sells SFI dual density foam for this reason. I run it in the rally Miata - put the soft overlay on for transits, then pull it when the helmets go on.
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