Brown Davis roll bar - fitment enquiry

[The Green Goblin]

Hey Gents,

i searched the internets + this forum regarding the fitment of this roll bar on an NB8B with hardtop, i just want to know if this roll bar touches the hardtop roof lining or comes into contact with anything else?

any other general comments welcome.

cheers,
Jas.

[93_Clubman]

They fit but can rub:
viewtopic.php?f=73&t=60981&p=765953&hilit=nb8b+hardtop+brown+davis#p765953

[The Green Goblin]

thanks for that.

i used this thread as reference in terms of pics & can see this guy has put some padding on the top right corner - which confirms what you are saying - viewtopic.php?t=29598.

can anyone with the BD set up comment around vibration noises & any other pain points? i am thinking about purchasing either the BD bar or the automotive plus single hoop torque box as seen here - http://store.automotiveplus.com.au/p/85 ... e-box.html.

at a glance the brown davis appears to sit higher - which is what i am after as im tall & would like my head to sit under the bar however, in saying that i dont want any scrubbing or vibrations, basically want good clearance all round. i looked at the tall boy options but this would mean moving my seat forward which is not an option for me, again due to height/leg room.

appreciate any advice on both these items. I am leaning towards the BD so far, but the scrubbing is changing my mind.

[hks_kansei]

The BD bar does sit higher, as it also sits slightly more forward than the MX5+

As for rubbing, it's very much dependant on the car, and the bar.
My BD bar clears the hardtop and soft top (very close to the soft-top frame at the corners, maybe 5mm gap) the hardtop is probably closer to a 10mm gap in the same area.

However, I have seen others with more space, and less. I can only assume that BD have a bit of leeway in their tolerances during manufacture. (and that the cars themselves all have different tolerances/wear)


The BD bar didnt add any rattles or noise to my car, and didnt rub anything.


The MX5+ bars are better designed and made than the BD though. If I had my time again I would go for it instead.
The tallboy shouldn't change the seating position, since it still sits at the seatbelt towers. So not really sure why that's an issue?


Regardless, if you want your head under a rollbar in an MX5 you pretty much need to replace the driver's seat.
I'm about 6ft even, and my head still stuck above the bar on the factory seat. I put in a different seat which bought me another 2inches of headroom give or take (a bit more if I take the seat cushion out)

[The Green Goblin]

thanks for the info.. interesting how the BD bar fits differently for each person/car.

the tall boy is brought forward (so that it peaks at a higher part of the roof) so it sits higher, becuase it's brought forward you lose some seat movement space. i have already replaced my seat with a sparco sprint v & i sit much lower now.. & i clear with my helmet on so no complaints there.

i like the look of the BD, also its slightly lighter on the pocket + comes with the cams paper, in saying that the mx5+ bar is well built, heavier on the pocket though & apparently takes longer to fit (labour costs).

in order my priorities are 1) protection in the event of a roll, 2) looks, 3) cost

so yeh.. now =

[hks_kansei]

Note that the CAMs paperwork must be asked for and purchased separately.
And from memory is only valid if they isntall it for you. (check on that last part, going from what I remember hearing years ago, so may not be valid anymore)

As for the tallboy bar, while it sits further forward than the normal MX5+ bar, it actually sits about the same position as the BD bar from memory (the BD sits slightly more forward than a normal MX5+)



The BD fitment differences are a combination of manufacturing tolerances (expected since they're done by hand if I recall)
and also slight differences with installation, my install was to put the rear plate over the carpet (sandwiching it as such) so my bar tilts forward ever so slightly more than if it were under the carpet.

One thing to note with the BD bar is that on the NB (and possibly NA8?) you will need to modify the backing plates for the rear arm bolts, as the NB has a captive nut under the panel they bolt to you will need to notch the plate to clear that (mine did anyway, maybe they've changed it since then?)



I chose the BD bar all those years ago for similar reasons to you, I think it looks better, and it worked out substantially cheaper (mx5+ was more expensive to buy at the time, then you needed to pay extra for powdercoating, then pay shipping from QLD to Vic.. the BD was ready to go and I could pick it up from BD themselves and save shipping)

You'll be happy with either bar, but I would say that while the Plus is the better bar, it's more a matter of if it's worth the extra cost to you.
For me it wasn't, and also when I got my bar MX5+ had only just started selling their bars.

[hks_kansei]

I just noticed you're in Sydney.

Another option for you would be an AGI bar, they're fairly new to the market, but a friend has one and it looks pretty well engineered (at least even to the other two bars)

It also has a higher main hoop than the BD, and maybe even the tallboy (havent seen a tallboy in person)

The catch is, it's apparently an absolute mongrel to install, and some people smack their heads on it because of it's positioning.
When I drove his car my head was directly under the main hoop and kept knocking it.


It's another option however.

[The Green Goblin]

thanks for the info mate - very helpful.

here is what i ended up finding out after speaking to a dude at BD around fitment.

- bar has been made the same (no variances in production specs) for 5+ years
- dude at BD is aware that some people have slight issues with the bar touching the roof, the logical explination he gave was that the roof rubbers/mounting points could either be sagged or generally worn down - depending on the age & condition of the car & roof. Also the install method of placing the mounting points ontop of the carpet, if you place the brackets beneath carpet it will lower it slightly.

he also told me some stories about clients in horrific accidents who had the BD installed, of which they came out alive.. the bar is engineered to withold such damage so i think it's upto the job. fact that it comes with relevant CAMS approval/compliance further solidifies that & is good incase i get pulled over. the guy was an elderly fellow & new his sh!t. so it looks like i will be purchasing this bar.

cheers.

[Mr Morlock]

If you can hit your head on a roll bar then it's totally unsuitable. You buy a product which has not been tested to an ADR. Road conditions are not the same as a race track where in the former situation rear end crashes are common place .

[greenMachine]

I have had two BDs, one polished alloy (ohhh, swoon ...), the second steel. Replaced the alloy as it was not CAMS compliant . Both fit with no problems, no rubbing on the several hardtops I have used. Fitting, and placement of carpet under/over bar make a difference.

CAMS paperwork not necessary, you can self-certify if you want to save a few bucks.

I say this regularly, it is not your height that is the issue, it is the length of your body above the seat - shortys can have a clearance problem, if they have short legs; tall people can fit ok if their length is in their legs. If you need that clearance, you need to sit in the car with helmet on, and use the broomstick test. As pointed out above, removing padding from the seat is one answer, replacing the seat is another (better) answer, bolting seat to the floor (no runners) is another. You need to try other peoples' solutions and see what works for you.

And if your head could conceivably touch the bar - proper rollbar padding! For you AND your passenger.

[Mr Morlock]

If you fit a roll bar presumably its strictly for safety reasons. You don't buy a roll bar based just on price. If bar does not fit properly because say of a person height then a big rethink is required perhaps even a change of vehicle. Wrapping on bars done of course but you or a passenger are not meant to come into contact with a roll bar or cage ,and people wear helmets, but it's patently clear that people still get hurt even wearing helmets e.g. Football esp in USA. Heavens knows what self certifying means - we see that this does not work in so many fields.

[forcedfive]

Self certify requires you provide the specs of the roll bar to CAMS and if it meets their requirements as to manufactirng materials, desogn and fastening method then you can obtains a CAMS certification for the bar and provide a sticker to be fitted to the bar. Of course it relies on the details being accurate.

Regardless of CAMS approval an aftermarket bar needs to be engineered for use on the road. At least in NSW. I suspect that most cars with bars fitted are not techniclly legal and engineered. If you can hit your head on it then is more likely to do damage than provide safety without the appropriate padding.

[The Green Goblin]

If you fit a roll bar presumably its strictly for safety reasons. You don't buy a roll bar based just on price. If bar does not fit properly because say of a person height then a big rethink is required perhaps even a change of vehicle. Wrapping on bars done of course but you or a passenger are not meant to come into contact with a roll bar or cage ,and people wear helmets, but it's patently clear that people still get hurt even wearing helmets e.g. Football esp in USA. Heavens knows what self certifying means - we see that this does not work in so many fields.

yes safety is obviously the main reason, not that i was concerned too much about price & willing to purchase a dearer bar, i just pointed out that my choice of the BD turns out cheaper.

as stated, i sit lower now with my bucket seat in.. part of the reason why i chose the BD is that it sits as high as possilbe & as back as possible without touching anything (hopefully), there is no point of having a roll bar if it's not higher than your head.

[Dweezle]

Unless your 5ft tall you won't be under a BD bar.
They are the shortest of the 3 we have available.

[hks_kansei]

Unless your 5ft tall you won't be under a BD bar.
They are the shortest of the 3 we have available.

I wouldn't say that.

My car has a BD, my girlfriend's has an MX5+ (normal single diagonal), and friend has an AGI

The BD is taller than the Plus by about an inch
The AGI is taller than the BD by about an inch (maybe more?)

The AGI sits furthest forward of the 3.
BD next, then the Plus, which seemed to sit slightly back from the BD's position (from memory, been a while since I looked at them side by side)


as for head space, depends on the seat.
I'm 6ft and my head is under the BD bar (about an inch under), my car has a Mazdaspeed B-Spec fixed back seat on OEM rails. If I remove the base cushion from the seat I gain even more headroom.