Outer Limits 4x4 Board

Last year when everyone was purchasing Goodyear MTRS, there was the big hoo haa about the legalities of this tyre.

Goodyear stated that it needed an 8.5inch width rim to run them, whilst legally we can only go to an 8inch width rim. Well 35's are not legal anyway......

Did anyone end up getting the MTRS passed through an engineer, or did everyone just take the risk and run them anyway.

Tried to search but all info is old now. So who is running engineered tyres 35inch+ on the road MTR or other?

Cheers

Tonka.

My Q78`s are listed on my report, but he is no longer with us

Did anything specific have to be done for the Q78's to comply? Or just said they were fine for the vehicle?

Nothing was said that I know of. It was done when the lux was in Sydney and I was in Albury. My bead lock rims are not on the report btw only the tyres on 8 inch rims.

What gets me is engineers say I want do 35 as they need a 8.5 rim but they`ll do 33`s their both the same bloody width tyre just the hight changes.

might be something to do with sidewall stability...

You can run the 315/75-16 (35x12.5-16) on an 8" rim.

the rolling diametre is the problem they have. In qld you ncan go something like 50% wider than standard and be legal, but over 15% on the diametre and it's not legal. Go figure.

I had BFG 35s engineered on 8" rims.
The engineer derated the weight limit and put it on the placard.
He also had a letter fromGoodrich stateing that was all that needed changing.
One of the reasons was also as the major tyre co's sell the tyres on a market where 8" is the max allowed rim.
Still more than enough for any 4x4.

Bazzle

bazzle wrote:I had BFG 35s engineered on 8" rims.
The engineer derated the weight limit and put it on the placard.
He also had a letter fromGoodrich stateing that was all that needed changing.
One of the reasons was also as the major tyre co's sell the tyres on a market where 8" is the max allowed rim.
Still more than enough for any 4x4.

Bazzle

Who engineered it
How much

Mere

$650 all up for all the mods. Engineer wont do individuals vehicles now.
Spoilt by too many taking vehicles to him and whinging about the work needed to be done to make them safe and legal.

Bazzle

I have 35x11.5x15 Centipedes (which measure about 36"x12.5") on 8" rims engineer approved for on road use. Need to do a test drive to check the brakes still worked OK, then a blue slip for RTA adjustment.
You just gotta find the right engineer I suppose.

I have 35" radial claws on 15x10 rims engineered.

all i am gunna sya is wot and engineer says is ok doesnt always mean it complies with the ADR's terefore is a waste of money havin it engineered if its still not street legal

ToNkA wrote:Did anything specific have to be done for the Q78's to comply? Or just said they were fine for the vehicle?

If your vehicles tyre placard requires speed rated tyres you cannot be legaly engineered AFAIK with Q78's. Other swampers are different i think.
I can (and will eventually ) get them engineered on my vehicle as it doesnt require speed rated tyres (82 LR) and the larges option of tyres was 900x 16 which is about 35'', so then the + or - 50mm rule can be engineered with 36inches.

Dave.

Mark Costello wrote:I have 35" radial claws on 15x10 rims engineered.

Its funny how poeple think an engineer is the final word ,
They are not the RTA is the final word and they have a specific guide line to which engineeres are supose to abide by ,
Its quite possibe you have these engineered on your papers ,and added to your rego , the engineer is really only a screening device so the rta dosn,t need to employ a heap of qualified engineers , The ability for him to venture into a GREY area or make a misjudgment is very real ,
The consiquence of this is when the shit hits the fan ,your on your pat malone. all that is recorded is the fact that an engineer signatory has
misquoted the guide lines in his report .

The guidlines state no rim size on 4x4s wider then 8" , unless proof the vehicle was supplied with rims of a larger size , Eg 1978 Blue Goat Game
Limited edition had standard 15x 10 rims , You may not own one But by using the diffs from this vehicle allows you to use the larger rims .

The problem with lawers and courts. The pleading of ignorance is not an exuse
for dissmissal of responsability , you would be better to plead -
dimminished responsability - drug use -alcholism- abused childhood -
If you ever get done for somthing try to fit one of the above to your needs ,

The limit for changing tyre diameters is not +/-50mm, or +/-15%; it is +/- 15 millimetres. Anything more than this requires engineering (unless you're in Queensland, where you need divine intervention. )

Scott

NJ SWB wrote:The limit for changing tyre diameters is not +/-50mm, or +/-15%; it is +/- 15 millimetres. Anything more than this requires engineering (unless you're in Queensland, where you need divine intervention. )

Scott

Sorry your right

I was thinking of track increase (+50mm).

Dave.

It is the brake fade that becomes the issue. I am trying to get my 35's engineered at the moment. My prob was that I hadn't adjusted the speedo after putting them on so my 10 times repeated brake test was done 8% quicker than it should have and my brakes faded too quick. 6th go.

I had already upgrade to discs on my 40, so I am going to let the tires down a bit more (try and reduce the radius) get my speed o adjusted. If that doesn't work I will try better pads, then maybe some ventilated discs.

Its what you have to do I guess and all about how much of the risk you are prepared to take on yourself. I have too much to lose so I will be doing mine squeaky clean.

DaveS3 wrote:

NJ SWB wrote:The limit for changing tyre diameters is not +/-50mm, or +/-15%; it is +/- 15 millimetres. Anything more than this requires engineering (unless you're in Queensland, where you need divine intervention. )

Scott

Sorry your right

I was thinking of track increase (+50mm).

Dave.

In Qld track increase is max 50mm on solid axles and 25mm with independent AFAIK.

My brother got told by the RTA that his 125mm was too much

Just run 'em anyway and hope for the best like I do!!!!!!!!!!!!

We havn,t said we don,t

I had the 35s engineered in Vic. The way it was explained to me is that the engineer is able to approve anything that goes beyond the ADRs by either testing, measuring or calculating.

Eg. the only way my brakes passed was by calculating that the tyres increased by 15% therefore the legal GVM had to be reduced by 15% This came down to a stupidly low figure but when you look at the troopy with a higher GVM (3300kg) and the same brakes, we could start there and reduce by 15% to get back to my original GVM of about 2800kg on the middy.

The big issue was the tyre and rim fitment guide IS the be all and end all of what you can do. It states that even a 33in tyre must be on a rim of at least 8.5 in.(regardless of what the manufacturer says, these are the rules for Oz) The problem there is that other legalities make 10in rims illegal so I had to find 8in rims that actually measured 8.5 in to keep the engineer happy.

Tonka - pm me if you want details of the engineer cos I'm not on the forum to often atm.

I have had several inspections on my truck and now on its second engineers certificate it was finaly ticketed last Wed and he said no way if i insist on 35's find some one else he checked every thing from the secondry bonet catch to the lights and the distance in from the edge of the car etc. It actural failed its first break test i would say it is the rolling dia of tyres and what the breaks are rated to from the factory that they are looking at.

Some things i dont have to have by law but was made to do because of safty reasons any way. I was told in Vic it is blanket 35's you carnt get engineered any more not by an engineer but by some one that uses them regulary. I had trouble just getting an engineer to take the job on there was no way i was going to push the point for 35's

Had a dude come up to me at Wandin while I was on the club stand asking about this today.. Hes been trying to find some1 to do them for his GU, hes called numerous, and none will do it. He wants a 4in lift at same time... Kev Williams seems to have pulled the pin on 4bs completely.

1 will do a total of 4inch' of lift, eg 2in tires, and 2in suspension, but that was it...