street dríven 5's and rollbars

[NitroDann]

I bet they require engineering to actually be legal, which almost none are.

Changing the wheels to stock sized is legal..... hubcap changes are legal... paint colour..... Technically adding a spoiler isnt legal without engineering, for pedestrian safety.

What im saying is that Id bet, just like sprint Vs that although they are said to be legal, they may be, but require engineering certification to actually be legal.

Dann

[lightyear]

I know a lot of people say that a roll bar adds stiffness, but that part of the car is very strong if you look at it. So I think it is in your head. I went from having every brace that you can have, to no braces at all and the car drives fine, with no need for braces. On a tight track like winton short I was the fastest car out there (almost). With no braces at all. If the car was to be faster or better in some way with braces, then the other cars that are a lot more developed (modified) than mine should have been faster. And the hardtop does add stiffness. If you think about a soft top, it has ribs sideways only. A hardtop gives you diagonal stiffness due to it being a solid structure. I am a sceptic by nature, so only by testing this myself and getting rid of the 100km/h wobble that was there with the soft top up or down, and with even a lightweight c.f hardtop the wobble dissapeared.
If you want a lightweight roll bar look at the one I made for my red car. It weighs about 5kgs. Basically, just a triangle shape protecting the driver.

[hks_kansei]

Sorry Dann, I can't comment on other states but in Vic Rollbars are legal as long as they don't sit further forward than the headrest, don't use the seatbelt bolts to mount, and are padded.

MX5 plus is legal in Victoria without engineering, Brown Davis technically not as it uses the seatbelt bolts (although it's a grey area as it doesn't only use them)

[NitroDann]

Rollbar stopped my 100click shake.

This has nothing to do with stiffness, but rather to do with changing the resonant frequency and damping the chassis at that speed.

the torsional stiffness of a car is not affected by 1mm of fibreglass and 4 rubbish clips, the fact that the rear mounts are flexible plastic is obvious enough.

Dann

[sailaholic]

Ahhh, now I see where you're going. Yes I beeline they do require the, mod plate, our atleast most of the ones I've seen have been plated for it ;-)

Sent from my GT-I9100 using Tapatalk

[zero00]

Danny

Must be the bar! missed PB at Lakeside by 0.37 secs last meet! I'll stick with the rollbar!!

[zero00]

sailaholic

Not sure of other States but I had mine done late December 2011 by MX5 Plus, has blue 'modification plate' attached and the leading edges MUST be foam covered before it leaves the workshop, Queensland Transport requirement but as I say, not sure about other States. If I choose to rip the foam off at least the installers have photographs to show it left their workshop meeting requirements

I think mine is called 'the lowboy', the taller model does not allow the seats to go as far back, I'm sure Danny can explain better

[NitroDann]

yeah so the bar isnt legal, but the people who make the bar can legally certify it, and do if you have them install it.

And there are other legal requirements like 50mm of padding of a certain grade also.

The bar itself simply isnt legal.

Dann

[lightyear]

Rollbar stopped my 100click shake.

This has nothing to do with stiffness, but rather to do with changing the resonant frequency and damping the chassis at that speed.

the torsional stiffness of a car is not affected by 1mm of fibreglass and 4 rubbish clips, the fact that the rear mounts are flexible plastic is obvious enough.

Dann

The hardtop did stop the shake. The roll bar does nothing for stiffness or the shake. I think the hardtop has enough of a stiffening affect to help. Maybe more so on mine, as I don't use clips-rather laser cut brackets bolted on.
Anyway this is about roll bars, so....

[zero00]

Again, it comes back to each State and their requirements

Pet 'hate' here in Queensland is that annual inspections are not required, so keep a car 10 years and it never requires a roadworthy BUT, go to sell it privately and you require one! I had a 94 Celica ZR which I sold in 2003 in mint condition except for a chip the size of a match head in the windscreen UNDER the parked wiper, the car was failed! Take a walk around any carpark up here and tremble!!

OK, scenario: If I choose to take the rollbar out and revert the car back to original, what happens to the modification plate?

[OurCognitiveSurplus]

I have an MX5 Plus Twin Hoop.

I didn't notice extra weight.
I didn't notice extra stiffness.
My reading of ACT law is that roll bar regulations only apply where the law requires the fitment of a ROPS. Because ROPS isn't required for an MX5 (unless you use it in a mine...) the MX5 plus bar doesn't breach the ROPS requirements. So it's in the clear.

The ACT uses the National Code of Practice for Light Vehicle Construction and Modification.

http://www.rego.act.gov.au/assets/PDFs/ ... %20ACT.pdf

The NCOP is available here:
http://www.infrastructure.gov.au/roads/ ... _ncop.aspx

See NCOP7 for ROPS.

Incidentally I think a failing of this forum is that people love to shout about crazy laws like "having a sticker on your window is illegal" or "you have to have a shift pattern or an after market gear-knob is illegal" or "a fire extinguisher is a modification which requires a mod plate" without ever bothering to cite a source other than 'some guy said...' or 'the cop told me that...'.

All that does is help spread misinformation because someone will then say 'I read on a forum that...' and the merry-go-round of making-stuff-up continues.

[vrmmmpshhh]

here in SA when a car gets defected they will basically want it returned to standard before it will pass. Exceptions are an intercooler and pod filter as long as it is secured properly. At the end of the day it comes down to how the inspector feels on the day. I got through quite easily even though my park lights didnt work and i had a torn steering rod boot. I doubt they will let a rollbar through even if it was ADR compliant.

I have noticed the overseas rollbars have the 2 rear arms coming through the parcel shelf which would be a huge problem. My old s13 had the rear speakers cut out to fit 6x9 speakers and they made me have a plate bolted in there with a detailed engineers certificate.

[Wivvix]

What's the consensus on parcel shelf bars vs chassis/floor bars?

The davis brown and mx5plus bar both bolt to the seatbelt tower and the parcel shelf.
The boss frog and hard dog roll bars bolt through the floor.
Which is more secure/rigid? Is the parcel shelf likely to hold shape in a roll over?

[deviant]

Something discussed and argued a million times with no conclusive answer. Personally I feel that a BD or plus bar are going to be fine in a 'soft' rollover but if you have a big one......

Again just my opinion but I dont see how the parcel shelf can provide a stronger mounting area than the floor of the cockpit or the boot floor. No idea why none of the local guys are making roll bars that avoid the seatbelt tower and mount to the floor or through the parcel shelf.

[Mr nanotech]

What's the consensus on parcel shelf bars vs chassis/floor bars?

The davis brown and mx5plus bar both bolt to the seatbelt tower and the parcel shelf.
The boss frog and hard dog roll bars bolt through the floor.
Which is more secure/rigid? Is the parcel shelf likely to hold shape in a roll over?

Actually HD don't bolt to the floor. Take another look at them. There is a shelf half way down behind the seats. They have an upside down L bracket type thing.
Here are some reference pics:





The only prob is that these can't be cams approved as they have the rear double diagonals. Cams only accept X Brace and single diagonals from top corner to opposite bottom corner. Otherwise I'd say buy one of those. The Hard Dog M2 hardcore are a better tested bar than what we have in aus and would trust one of them more than our domestic ones.
Not a fan of the BD bars...