roll bars, 50mm clearance and tall people

SteveS1 · Postby **SteveS1** » Mon Mar 10, 2008 1:46 pm

I finally got around to test fitting the BD roll bar to the mx5 and realised that there is no way I'll ever be 50mm beneath it with a helmet on, as required by CAMS. I'm 189cm (6'2\"). Even if I sat on the floor with no seat, i could not fit.

I'm intending to have a go at a bit of racing in the future, so would prefer to keep the CAMS requirements in mind.

So I'd still like to keep the car street registered, and a roof would be handy. So i see my only option is to get a taller version of a BD roll bar, and simply bolt it in for track days. Obviously I'll have to keep the seat as low as possible as well.

Is this what other people are doing? is there an off-the-shelf bolt in taller roll bar?

PS I weighed the standard MX5 seat at 17kg, whereas a fiberglass seat was 6.5kg or so.

Postby **Okibi** » Mon Mar 10, 2008 1:50 pm

SteveS1 wrote:...is there an off-the-shelf bolt in taller roll bar? ....

Not that I know of, if there was an easily bolt in/out solution produced locally i'm sure they'd sell a heap.

I wonder if those "no bolt" sprung clips they use for scaffolding could ever pass cams regulations.

kula · Postby **kula** » Mon Mar 10, 2008 2:03 pm

wow, u must have a really tall torso and short legs..

Im 188cm, and fit well under a BD bar with a sparco sprint seat even with a helmet.

Cal · Postby **Cal** » Mon Mar 10, 2008 3:04 pm

Do you need a roof? Just get a taller bar and a tonneau cover.

SteveS1 · Postby **SteveS1** » Mon Mar 10, 2008 7:45 pm

wow, u must have a really tall torso and short legs..
Im 188cm, and fit well under a BD bar with a sparco sprint seat even with a helmet.

i do have a big head - perhaps thats it hey!

Do you need a roof? Just get a taller bar and a tonneau cover.

i did think about that Cal, and I kind off like the idea in an old Austin Healy kind of way, although i wondered how effective a tonneau would be in a modern car loaded with electrics, and whether the cops would give me a hard time.

Alex · Postby **Alex** » Mon Mar 10, 2008 10:29 pm

Even if I sat on the floor with no seat, i could not fit

wow, you must have very short legs then

irwin83r · Postby **irwin83r** » Mon Mar 10, 2008 10:56 pm

im in your boat and i think helmun too (though helmun is just really really tall) im just like you.. long in the torso..

the fixed back sprints wont lower you all that much untill you bolt them to the floor.. and then its hard to keep road legal.. if you use the factory sliders and bolt to that you may end up an inch lower if your lucky.. (pending on the seat... apparently the new sprint V is the way to go..) but this isnt getting me anywhere near low enough.. the lowest ive found is actually removing some foam from the standard seat seems to sit lower than a sparco ultra on the floor ridges. or atleas i think thats what helmuns car was on??

im planning on taking the car to an engineer and seeing what im aloud to do with the floor pan and those ridges the standard seat mounts too, IF i cant make my own brackets that sit the seat low enough between the ridges.

SteveS1 · Postby **SteveS1** » Mon Mar 10, 2008 11:25 pm

i tried sitting on a flat fiberglass seat base with padding removed and it was still too high. the BD roll bar is just too low.

I'm certainly not alone with the height issue. I'm just running through the options, which I guess are:
(i) taller roll bar permanently mounted with no roof, but perhaps a tonneau cover
(ii) taller roll bar which can be bolted on for track use, but removed for daily use so a roof can be used.

on the seat issue I'd probably go with a fixed back seat bolted to the floor without sliders. i presume there'd be no defect issue with this approach.

Postby **Okibi** » Mon Mar 10, 2008 11:30 pm

Yup I have the same issue, I wouldn't have enough clearance when wearing a helmet even if i was sitting on the floor.

Cal · Postby **Cal** » Tue Mar 11, 2008 10:17 am

SteveS1 wrote:i did think about that Cal, and I kind off like the idea in an old Austin Healy kind of way, although i wondered how effective a tonneau would be in a modern car loaded with electrics, and whether the cops would give me a hard time.

I would not worry about either issue. We transport plenty of race cars all over Australia in all sorts of weather with this setup and I've not heard of anyone having issues with electrics getting wet. Can't see why the caps would care.

Hellmun · Postby **Hellmun** » Tue Mar 11, 2008 9:48 pm

I don't clear the hard-top by 2 inches if I sit on the floor with no seat in the car.....

Hellmun · Postby **Hellmun** » Tue Mar 11, 2008 9:50 pm

We need to rent midget look-a-likes to get through scrutineering.... or simply remove the roll-bar removing the problem altogether which is kind of sad. Though I am curious to try a lap of the circuit with no roof one day. I have yet to not be running the hard-top.

CapitalF · Postby **CapitalF** » Tue Mar 11, 2008 11:26 pm

I too have this problem and at the last Autocross I attended they pointed out the issue with my BD bar/head height. I pointed out the car was not log booked, nor was the bar required by the rules at all, at the same time politely acknowledging the real safety issue and its my personal well being at heart. They let me race.

Ive put 3 different race seats with slides in the vehicle to test and none are lower than the original Roadster seat.

I have intentions for a full roll cage with added height in the hoop and either a tonneau cover or customised hard top. Has anyone looked into adding 3 inches to the rear of a hardtop to lift it higher. I think the hinges at the front would cope with that. Realistically though a tonneau cover would be a lot cheaper /easier...

Peter