Anyone in NSW got tyre mods Engineered?

[rainsey]

Hey all,

RTA rules state the following:-
1: 26mm wider than standard (have gone 42.3mm)
2: 15mm over largest diameter (84.5 mm over)
3: Track no more than 25mm (Do not know how this is possible but 100mm over)

Which negates probably most of the tyre mods available. Rang the engineer that did my body lift and palmed me off saying I would have to have brake tests and handling tests and basically stated too expensive and not worth it.

An all I have done is gone from 245/70 16 to 285/75 16. Visually not even noticeable but insurance wise a no go. Anyone out here engineered their wheel changes or do I stay with two sets of wheels ( those for rego and those for play)??

Cheers

Rainsey

[pongo]

Best way , If you get in a acco, get it towed home to your place, change tyres and then get it inspected. If you can do it itll all be sweet

[plowy]

tuggerah tyre power is doing tyre engnering give em call

[rainsey]

Fair dinkum....

Are they an engineering signatory that the RTA recognises??

If so I should have gone there for my tyres in the first place!!

Cheers

Rainsey

[MissDrew]

I had my hilux engineered with 33`s on it, even have a new tyre card on the inside of the door opening that says 33 x 12.5 x 15.

[Beastmavster]

The new Dotars agreeement was - 1.5x over tyre standard width if beam axle 4wd. This was apparently signed off by ALL states in January 2006.

I would strongly suggest you grab a copy of it and print it out then go have a word with your engineer about how they interpreted those rules. They seem to be using the "passenger car" tyre and rim settings. Ask them WHY they're screwing you over.


This seems to be happening with a lot of 4wd ppl in NSW now. If you're getting the engineering done by a normal passenger car engineer go to a reputable 4wd shop, cos I think you will get different answers. nothing new there at all - we've faced that crap all along with engineering rules.


Maybe NSW has instructed it's engineers to "interpret" things differently but except for a couple of miswordings and vagaries on the below 50mm lift area it's pretty black and white really.


50mm tyre size over largest factory diameter for all 4wd's. If your largest factory diameter is officially 749 (245/70/16) then this allows 799mm or 31.4". Sorry - that aint a 285/75/16 and it isnt even close.

However believe it or not there ARE 245/70/16 tyres in a range of sizes up to 805mm - my hint would be to check out the Simex Australia website - which means a set of 833mm 285/75/16 is "potentially" legal. That will fark them - I've mentioned it in the new dotars thread.

Dont think that is an OEM fitted tyre though - but there are others that are that are bigger than 749mm so you should be able to run at least a 32" with no problems.

50mm widest offset over largest factory standard (Beam axle) or 25mm (IFS).

Suspension lift max 2" now and 3" body lift - total max lift 150mm.



As such you should be able to get the following on say a normal patrol or cruiser, hilux etc.

-25mm rim offset (Patrol) or -35mm (Cruiser) - extra 50mm wider.
51mm suspension lift
75mm body lift
25mm tyre height increase (max) from tyres with up to 50mm over standard diameter. *


* this is the one vague bit of the legislation sicne it specifies you can use any OEM tyre. Some OEM tyres are larger than others... have fun hunting

Certainly 33"s can be done legally, and maybe even 35"s depending on how big an OEM 7.50R16 we can find. My best size so far is a 32.4" Wrangler TG..... OEM and all .... +2" is juuuuuuuuuuuuust short of the
34.6 of most 35" rubber. :(

If I was down south I would have rushed to get my stuff engineered beforehand. Now you're basically stuck with those new rules if the states are enfocing them now.

Here in QLD therse are softer regs than we faced so we could do what you guys could.



In the end though, as before, what you can get legal is what you can get an engineer to sign his career off on......

[Beastmavster]

Here's the exact tyre size clause:

"The overall diameter of any tyre fitted to an off-road passenger vehicle or a commercial vehicle must not be more than 50mm larger or 26mm smaller than that of ANY tyre designated by the vehicle manufacturer for that model."

Usually you have 2 brands to choose from in your owners handbook, and maybe 2 tyre sizes to choose from. To use myself as an example, Lucky Patrol owner I am I get 3 to choose from with 7.50R16 being considered the largest option.

Normally a 7.50R16 is considered to be a 32" tyre - most are about 31.8" in real diameter, although 32.2" and 32.4" are also common sizes.

I dont know exactly how big (in mm) the 7.50R16 were that could have been fitted to my 4wd at the first owner's choice.


Now the most restrictive interpretation I can see on this is that it means it has to be the OEM tyre spec of the vehicle as delivered in Aus that you base your +50mm on. Good luck finding that info on an older car like mine.

However it is open to interpretation that any tyre designated 7.50R16 is acceptable as your base.

[Slunnie]

The engineer signed off on my tyres. I went from 235/70-16 which is a 29" (though the Disco also comes with 255 wide 29's) to a 285/75-16 MTR's and 34x11.5-16 Simex JT2's. The RTA specifications are for trucks that are not engineer approved.

[65Mog]

The RTA specifications are for trucks that are not engineer approved.

Thats not exactly true, the RTA has the final say in whats road legal, it doesn't matter if it's engineered or not.

[Beastmavster]

Exactly.

Slunnie's mods would have been approved before the new rules too...

[slosh]

The new rules probably aren't that bad, because I tried to get 35's (315/75 x 16) engineered on 80 series diffs under the old rules and found it too hard. I did find an engineer who would pass the size, but not the -25 offset I needed. At least now the offset is allowed, and the rules are more black and white.

We know that at minimum 34's should be passable on the bigger trucks, and as said most engineers would have been reluctant to pass this b4 (how many threads came up on here about trying to get 35's passed?) but now they can. The little trucks just have to get the big diffs if they want to run the taller tyres.

With reference to rainsey's original post, either the engineer u r talking to is quoteing the rules for passenger cars (that's all 99% of people seem to know about) or they are not allowed to approve the +15mm to +50mm tyre increase yet because lane change test facilities are not up and running.

[Charlie]

15mm over largest diameter (84.5 mm over)

You can only increase you tyres 50mm ,I don't see any way arround this under the new regs. In my dealing with engineers they have calculated the tyre size ,the actual physical size should be within 3%.
Regards Charlie

[Wooders]

15mm over largest diameter (84.5 mm over)

You can only increase you tyres 50mm ,I don't see any way arround this under the new regs.

Individually constructed vehicle

[Screwy]

mine got passed on 35x12.5 on 15x8

stock is 31x10.5 on 15x7

[cj]

mine got passed on 35x12.5 on 15x8

stock is 31x10.5 on 15x7

When? Is that before or after the NCOP was introduced in Jan?

[65Mog]

15mm over largest diameter (84.5 mm over)

You can only increase you tyres 50mm ,I don't see any way arround this under the new regs.

Individually constructed vehicle

Yep thats a great idea, spend 4 - 7 grand on an engineers report so you can run larger tyres

[Slunnie]

When? Is that before or after the NCOP was introduced in Jan?

Has it been formally introduced yet?

[Beastmavster]

Yes... that's been signed off in January.

As to exactly when each state starts using/enforcing it is up to them. NSW and TAS already are.

[Screwy]

nah mine was done in like september last year....

[Beastmavster]

That would be why you're allowed 35"s then.

[Beastmavster]

15mm over largest diameter (84.5 mm over)

You can only increase you tyres 50mm ,I don't see any way arround this under the new regs.

Individually constructed vehicle

Yep thats a great idea, spend 4 - 7 grand on an engineers report so you can run larger tyres

Compared to what some people spend on their rigs that isn't really that unreasonable..... I've certainly spent that sort of money on mods on my last few rigs.


I agree with this really - if you wanna run 44" truck tyres then reallly there needs to be a more stringent set of guidelines. At least there is a way to do it - at a cost.


If you only wanna run rubber that big for comps - and run 34"s on the road then take the car or the tyres up there in a trailer.


The comp scene is more going to buggies anyway so it's less of an issue to have the vehicles legal on 38"s or whatever now anyway.

[munecito]

This guy got his Zook engineered last week with 33´s on 8´s

http://www.outerlimits4x4.com/PHP_Modul ... =33s+on+8s

Will

[Wooders]

15mm over largest diameter (84.5 mm over)

You can only increase you tyres 50mm ,I don't see any way arround this under the new regs.

Individually constructed vehicle

Yep thats a great idea, spend 4 - 7 grand on an engineers report so you can run larger tyres

The comment was there was no way....well there is....I didn't say it was cheap
I think there are f ew other ways too - but at the end of the day if you want to run big tyres properly it's not cheap.....

[Wooders]

...............(double post)..........

[Charlie]

Fair enough if Rainsey asks how to register his rig as an individually constructed vehicle I’m sure people will help him out.
I was responding more to the idea you could choose the tyre with the biggest physical size rather than the calculated size to add 50mm to. I understand the argument but would hate to end up testing this court, there are a few counter arguments you can apply to this line of thought.
Regards Charlie

[Beastmavster]

well the first draft sort of had a calculated size. I think that may still be the way it was to be interpreted - I'd want it in writing from my local transport department before I went bigger than 255/85/16 anyway.

[Charlie]

Beastmavster I’ve no problem with the your very balanced view on this topic but it’s been presented as fact on other forums that you just grab the biggest tyre you can find and go from there, I’d be very careful going down this road .

[Beastmavster]

Agreed.

I would be very careful doing it to...... it's arguable but it's not something that I'd want to be using in court to save my a$$.

Hearsay on the internet is not fact.... (contrary to popular belief).

Maybe someone has managed to achieve that and maybe it IS possible that it would be interpreted that way if something happened.

There's also a clear difference between researching which biggest tyre you can fit with a certain marking, and then extrapolating it another 50mm.....



Me personally, I'd get it in writing from my RTA first and stay within the letter of the law - that's why I got the Patrol as opposed to my old Zuk on 31"s.

However there are plenty of people out there who dont really care, or want to stretch it as far as they can. At least they can play the "plausable deniability" card.

[plowy]

as for hear say my mate took his rig to the engineer and asked him about the new laws comming into affect

as im doin mods and im trying to beat this so called dead line

the engineer said there is no date as yet as rta don't agree with most of the rules that are trying to be instated

but as i said its here say don't go rippin my head off

[Vulcanised]

as for hear say my mate took his rig to the engineer and asked him about the new laws comming into affect

as im doin mods and im trying to beat this so called dead line

the engineer said there is no date as yet as rta don't agree with most of the rules that are trying to be instated

but as i said its here say don't go rippin my head off

i spoke to an engineer who said the same thing...... and that was after january. Some are adopting them...... a lot in Sydney are apparently.... some still aren't. The concensus seems to be that there is a lot of confusion regarding the rules........ i'll get mine engineered if i can when i get the engine swap done..... if not, i'll just get the engine swap done and be happy with that. A friend got his Mav engineered with a 7" spring lift and 35" wranglers a couple of weeks ago in Kirrawee