Slyp_Dawg HalfDork
10/16/14 10:36 p.m.

I know basically any trackday organization/track will require at least a roll bar in a convertible for it to pass tech, and the accompanying broomstick test. If the convertible has an available hardtop and it's securely/permanently bolted down (IE a Miata with the hardtop using the Spec Miata plates instead of the regular latches), would that change the roll bar requirement any, or do they still treat the car as if it's a convertible? my Miata has a HDHCHT bar, but at 6'0" with a decently long torso, there's absolutely no way I'd pass the broomstick test with the stock seats. going to an aluminum seat bolted to the floor is definitely an option and something I'm planning to do, but I'm not certain that will get me enough helmet clearance to pass the broomstick test without the top on. Anyone have any input?

Keith Tanner
Keith Tanner GRM+ Memberand MegaDork
10/16/14 10:48 p.m.

Ask the guys running your track day.

turboswede GRM+ Memberand UltimaDork
10/16/14 10:48 p.m.

Depends on the organization, the track, the car, the insurance carrier, the way you ask and whom you ask. Basically, there's no hard and fast rule. You have to ask the folks running the event(s) you wanna run.

Slyp_Dawg HalfDork
10/16/14 10:55 p.m.

I haven't signed up for one yet or even figured out which one I want to do, I know it will be at either VIR (extremely likely, family has a farm about 30-45min from there) or Summit Point (could probably camp or get a hotel). My biggest concern right now is failing the broomstick test by about 2" on the stock seats... I'd assume bolting a Kirkey or similar straight to the floor would lower the seating position enough to pass said broomstick test?

codrus GRM+ Memberand Dork
10/17/14 12:06 a.m.

While it's certainly true that you should ask your event organizer, the general answer is that a Miata with a bolted down hardtop is no safer than a Miata with no hardtop. It's fiberglass, it provides no additional rollover protection.

I have seen track days that didn't allow any convertibles without a full roll bar and a bolted down hard top (mainly BMWCCA), but I've never seen one where the hard top made a difference to a car that didn't have a roll bar.

I've also never seen a track day that actually tried to enforce a broomstick test.

Bolting a Kirkey to the floor makes less difference than you might expect. You'll gain some height that way, but not much more than you would with a foamectomy. If you want lots of gain, you need to cut the rear seat mounts out of the chassis and THEN bolt it to the floor.

Cutting out the seat mounts and bolting a seat to the floor (a Recaro Pole Position, rather than a Kirkey) dropped me about 3.5 inches, which was great.

Gieb New Reader
10/17/14 8:39 a.m.

As codrus mentioned, I've never seen any organization actually enforce the broomstick test. I did track days this summer with 3 different organizations and never had an issue. I wouldn't pass the broomstick test without adjusting my seat forward and then reclining it under the bar.

bigmackloud New Reader
10/17/14 8:43 a.m.

So you do or don't have a hardtop now? I have a miata with the hardtop and have run at VIR with TrackDaze, SVT Cobra Club, and NASA. None have ever checked my head clearance. I think the basic assumption is that if you fit inside with the hardtop on, then you're good.

That said, and regardless of the requirements of any track or organization, consider why head clearance is important to you from a safety standpoint. You really don't want your head above the rollbar (hardtop or not) in a roll over.

I've got the Momo Start fixed-back race seats, on the stock sliders. They fit me like a glove (I'm only 5'10" though). My head clearance is ok, but I'm planning to remove the sliders on the passenger side as I want to make sure any instructor I get is equally as comfortable and safe.

I vote to get racing seats and bolt them straight to the floor. I think they will likely give you the clearance you need. And be sure to do the passenger side too for your instructor.

kreb GRM+ Memberand SuperDork
11/4/14 10:10 a.m.

I was at my first trackday in a while at Laguna Seca last weekend, and it was clear that these guys ran a pretty loose event when I saw a Porsche convertible being run with only some sort of style bars. I guess that they're considered OEM roll protection, but the driver and passenger's heads were sticking about 3 inches above them. On top of that, one of the drivers was very inexperienced and being passed by drivers going 40 MPH or so faster.

WTF! I'm amazed that the track management allows this E36 M3. With that sort of speed differential and no driver classing by experience, you've got the makings of a fpotentially fatal accident. In that case, does Mazda really think that whatever insurance that they require of track day operators is going to be enough? Can you say "deep pockets"?

I've run track day events with three organisations. The only one that takes safety seriously is NASA (I'm in their home region btw). A few years ago, the NASA boss felt that some of their instructors were getting lax and made all of their instructors recertify themselves. They have a full compliment of corner workers and a careful skill-based classing system. I've seen them pull guys off of the grid because they didn'ty like the seatbelts that someone was running. These other yahoos (One of which is affiliated with a prestigious marque) let you self-inspect, run with whichever group your inflated ego puts you in, offer no instruction and a skeleton staff. I think that this is potentially very bad for our sport. Cars are just too fast to treat a track day with less safety in place than your local 6 HP go-kart track.

rant-off. But seriously WTF!?

Driven5 HalfDork
11/4/14 11:56 a.m.

I too have never seen the broomstick test performed. Most track day and HPDE organizations I've encountered tend to allow street driven convertibles to use factory roll over protection or aftermarket roll bars that are simply built as close as possible to the interior of the top, regardless of ultimate height. This is a pretty standard concession resulting from the commonality of sporting convertibles where it would be physically impossible to have both a functioning top and a rollbar that passes the broom stick test for taller drivers. Interestingly enough, even SCCA PDX appears to allow for just the use of a factory hard top without a rollbar.

evildky Dork
11/4/14 12:03 p.m.

The new SCCA PDX requirements are pretty lax. I was lapping the new NCM track in my stock miata with a regular hardtop latched on no bolting required.

boileralum New Reader
11/4/14 3:54 p.m.

@kreb - I know on at least some of the 911 cabriolets, the roll hoops extend automatically under certain conditions. Unfortunately for the driver of one at a track da I attended at Grattan several years back, going over the hump and getting the rear wheels in the air was enough to trigger it, and somehow the impact was enough to shatter the back window of his hard top.

chiodos New Reader
11/4/14 5:32 p.m.

Have you performed a foamectomy on your seat? Makes a huge difference in feel and you can take out a ton of foam I'm sure 2 or 3 in or so if not more

fiesta54 Reader
11/5/14 11:47 a.m.
bigmackloud wrote: That said, and regardless of the requirements of any track or organization, consider why head clearance is important to you from a safety standpoint. You really don't want your head above the rollbar (hardtop or not) in a roll over.


My dad had some guy pull a pit maneuver on him going into T1 at VIR and it rolled him. He was in an Elan and his belts stretched a little and he had scrapes all down his helmet from the racing surface. Luckily he was still just low enough in his seat to avoid any real injury. Needless to say he got a new rollbar that was several inches taller.

Leafy Reader
11/5/14 11:54 a.m.

Heck depending on the club some of them will let a miata run with just the top bolted in place and no roll bar.

dean1484 GRM+ Memberand UltimaDork
11/5/14 1:21 p.m.

Some one once said to me that if you are not smart enough to provide enough protection for you head in event of a rollover you probibly did not need it anyway.

Driven5 HalfDork
11/5/14 2:35 p.m.

I installed different roll bars in both of my Miatae, each specifically chosen based on its intended uses, and would recommend against making the decision lightly of which particular bar to install on any street driven Miata. The tallest bar is not necessarily the best one! While you don't want your head above the roll bar in a roll over, you also don't want your head near a roll bar in a street collision. Consider that in a Miata, in order to get a bar that is compatible with the soft top operation further above your head, it must also get closer to your head. Thus bars that are safer for your spine in a roll over at the track, when used in conjunction with a helmet, actually become more dangerous to your head in the (by far) most common types of wrecks on the street.

4shadesofblue New Reader
11/28/14 11:36 a.m.

I had this issue last year when I started tracking my miata. I have a Bossfrog Maxx 6pt bar and I was not able to get low enough to pass the test. My first step was to cut most of the foam out of the stock seats, then to cut the rear bumps of the floor and I just cleared. I used this for two event then I went to Race seats bolted to the floor. If I had to do it again I was just start here. The race seat with a harness really helped my driving by holding me and letting feel the car better. I have an Untrasheild road race seat that has work very well for me.

I would look for a hard top if you are going to keep the car. It stiffens up are the car quite a bit, and the you gain a little top speed. It by far has been one of the best improvements that I have made. I have also had the problem with not being able to run with some local clubs with out one. The BMW club event is one the of the best event at BIR and without a hard top they will not let you in.

If you ever want to sit in my car with seat just PM me and we can set something up. I think you are pretty close to me

Rusnak_322 Dork
11/28/14 3:56 p.m.

I had a NB and a factory hard top. Never tracked it, but I can't belive that the factory latches did anything to stiffen the car at all. The Frankenstein bolts by design allow movement which would negate any rigidity.

BoxheadTim GRM+ Memberand UltimaDork
11/28/14 4:10 p.m.

The NAs I owned did feel stiffer with the hardtop on provided that the side latches were in place. But that's via the butt-o-meter, not via any scientific measurement.

4shadesofblue New Reader
11/28/14 7:17 p.m.

In reply to Rusnak_322:

In my 90 NA it made a big difference, the NB is a lot stiffer from the factory. I also put shims under the latches and adjust the rear catches so they are tight on the Frankenstein bolts

LanEvo Reader
11/28/14 8:41 p.m.

As an instructor, I wouldn't get into the shotgun seat of a Miata (or Boxster, Z3, S2000, etc.) without adequate roll protection. There was an incident at Mosport with an E46 M3 cabrio with stock, pop-up roll hoops. Never again.

Rusnak_322 Dork
11/29/14 9:37 a.m.

I think the hardtop just made the windshield frame flex less which makes the car feel stiffer but does nothing for handling.

Driven5 HalfDork
11/29/14 10:02 a.m.

Regarding a foamectomy for helmet height clearance at the occasional track day, I did a light foamectomy to sit me a little lower, but I also didn't want to take a ton of padding out for street use either. So what I did was remove the bottom seat cover before a track day. That way when I got to the track, I could simply pull the bottom cushion and replace it with some of that thin camping pad foam. Sitting pretty much directly on the seat pan, with just a sliver of padding, was comfortable enough for a days worth of track sessions while getting me as low as possible, without making any major changes to the car or incurring any significant expenses. Then when I was done for the day, I just popped the thick and comfy mostly stock cushion back in for the drive home, and zip tied the seat cover back in place whenever I had the opportunity to after that.

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