NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

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twr7cx
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NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby twr7cx » Sun Jan 13, 2019 10:53 pm

Anyone with either a Brown Davis or Automotive Plus roll bar in their NA or NB able to advise on what the distance is from the top of the roll bar to the centre of the top of the front windscreen frame?

e.g.

Image
Picture borrowed from Hard Dog rolls bars in the USA < https://trackdogracing.com/images/produ ... _x_d.3.jpg >

ianoz
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Re: NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby ianoz » Mon Jan 14, 2019 1:49 pm

interesting - i'd always assumed all Brown Davis bars were the same size but looks like it's not the case;

Measured from the middle of the main hoop bar (ie add 22.5mm to the back of the bar, subtract 22.5mm to the front of the bar)

NA with Brown Davis 'plastic window' model (diagonal bar runs at an angle to back left).
IMG_8821.jpg


NB with Brown Davis 'glass window' model (diagonal runs straight across between seats)
IMG_8820.jpg


The 'glass window' model is also about 2cm taller than the 'plastic window' one.

hope that helps. :D
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hks_kansei
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Re: NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby hks_kansei » Mon Jan 14, 2019 2:12 pm

ianoz wrote:interesting - i'd always assumed all Brown Davis bars were the same size but looks like it's not the case;


I'd expect a lot of that is just manufacturing tolerances, on the bars, and slight differences in the chassis of the car itself.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)

twr7cx
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Re: NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby twr7cx » Thu Jan 17, 2019 9:08 pm

Thanks for providing those measurements ianoz. Was interested to compare to my Hard Dog M2 Sport bar as the Brown Davis seemed to have the main hoop a bit further rearward which is a bit further away from your head - your measurements show that they’re between half an inch to an inch further back - which would be great for extra head clearance!


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hks_kansei
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Re: NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby hks_kansei » Fri Jan 18, 2019 8:58 am

Bear in mind that the further back they sit, the shorter the height needs to be to fit under the roof.

So the gain in "not cracking my head open in a rear ender" is offset by "cracking my head open in a rollover"



Headroom wise, of the Aussie options, it goes:

(Tallest - Shortest)
AGI - Brown Davis - MX5+

And of the 3, their fore/aft location is the same order, with the AGI being pretty much directly above your head, the BD being just behind the seats, and the MX5+ being only a little bit further back than the BD.
1999 Mazda MX5 - 1989 Honda CT110 (for sale) - 1994 Mazda 626 wagon (GF's)

twr7cx
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Re: NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby twr7cx » Fri Jan 18, 2019 5:05 pm

That's some great information, thanks hks_kansei. Sounds like the AGI would be very similar to the Hard Dog then in terms of positioning.

Personally, if I was every buying again, I would go with the further back options. Sure they reduce roll over protection, but you still have more of that than when the car left the factory, but the reduction in risk to head injury from any other accident would be very beneficial. I have the Hard Dog foam on mine and am about to fit NB2 'surf board' seats into my NA in effort to reduce the head risk - but in reality it might all be for naught anyway as the metal bars of the soft top still pose a danger to us taller folk...

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Re: NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby Corey » Fri Jan 18, 2019 5:11 pm

twr7cx wrote:That's some great information, thanks hks_kansei. Sounds like the AGI would be very similar to the Hard Dog then in terms of positioning.


Unless AGI changed their design, it will sit lot further forward than the hard dog. My agi bar measures at around 23.2 inches from the front widnscreen, which is why I'm looking to get a new roll bar.

twr7cx
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Re: NA/NB Brown Davis/Automotive Plus Roll Bar distance from windscreen

Postby twr7cx » Fri Jan 18, 2019 9:00 pm

Corey wrote:
twr7cx wrote:That's some great information, thanks hks_kansei. Sounds like the AGI would be very similar to the Hard Dog then in terms of positioning.


Unless AGI changed their design, it will sit lot further forward than the hard dog. My agi bar measures at around 23.2 inches from the front widnscreen, which is why I'm looking to get a new roll bar.


O wow, your right, that's a long way forward! I believe that there is a variant of the Hard Dog bars which is around 23.5", but that's the full track racing spec. The others are around 26.5".


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