Tyres - how big is legal ???

I am interested in Bajaifying the Kombi as i mentioned in other threads, so I have been trying to find out what is legal and how strict the regualtions actually are.

Tyres
The guy who did my mod plate told me only 15mm overall diameter larger than STD is acceptable. Is this right?? Is there a way larger tyres can be complianced??? Or is everyone running fat tread running the gauntlet??

And does anyone know what the standard tyre size was on a 76 kombi anyway???

Col

I have 10.5 mud terrains on 15 x 7 " rims on the back of my 75 twin cab, and 215mud terrains on 15x6 on the front. but would be better on 15x7", same as the back. been on for about 5yrs and never been questioned about them

Nice wheeels, what are they? what is the diameter of your wheel tyre combo Frt and Rr.... thanx in advance
tony g

front are 15"x 6" and are standard mercedes benz, back are the 15"x7", using the centres only out of a standard rim they are rewelded offset into a 7'' rim. but It would be better to use 4x7 " rims
I have just ordered 2 more for the front , whichwill give me 6 ( 2 for the spares, as i have 2 different tyre sizes)

front

Hi

This what the RTA in NSW says, I believe that the QLD rego people have the same requirments.

" The outside diameter
of the wheel and tyre combination must be no more than 15mm over the largest diameter wheel and
tyre combination specified for the vehicle and not more than 15mm below the smallest diameter wheel
and tyre combination specified for the vehicle."

1302Steve

The QLD rules do (or at least did) say the largest wheel can be up to 130% larger than the largest optional wheel from the manufacturer. This is worded wrong, it should have said 30% larger or 130% or the original, not 130% larger. So basically they cannot legally fine you for having tyres that are anywhere up to 230% of the original width. My engineer told me this.

Strangely my Baja mod papers says 15x6" and 15x8" on it. What that means nobody really knows but every seems happy that it lets me run 15x6" and 15x8" rims with whatever tyres.

I have heard some people say 15x8" is ok, cos they treat it as an offroader which can have 150% larger tyres. Someone reckons the largest option rim is 5.5", so 150% x 5.5" = 8.25" rim.

As you can see the rules are written really bad so it is possible for some cars to get approved differently to others. If you have it on paper somewhere you'll be right.

Apparantly the rules will change again soon. The RTA rules already have changed a little (Nov 2003). They now say...


Rear wheels
The maximum permitted rear rim width for a particular vehicle is determined by its unladen weight (10 litres of
fuel, no occupants or luggage) in accordance with the following tables:
Front wheels
Front wheels shall be:
• No wider than the maximum permitted for rear wheels on your vehicle or 204mm (8 inches).
• No narrower than 70% of that fitted to the rear wheels.
• No narrower than a standard wheel fitted to the your vehicle as original equipment.
Vehicles built to comply with ADR 24 (after 1/1/1973 for passenger cars)
Vehicles that were not built to comply with ADR 24 (prior to 1973 for passenger cars)
Note: 25mm increase in wheel track limit also applies
Note: 25mm increase in wheel track limit also applies
Allowable rim width increase above the widest optional
wheel available for the axle assembly used Unladen weight
Up to 800kg
801 - 1200kg
1201kg & over
26mm (1inch)
39mm (1.5 inches)
51mm (2 inches)
Maximum rim width
Up to 800kg
801 - 1000kg
1001 - 1200kg
1201 - 1400kg
1401kg & over
153mm (6 inches)
178mm (7 inches)
229mm (9 inches)
204mm (8 inches)
254mm (10 inches)
Unladen weight

Or view it in a readable format here...
http://www.rta.nsw.gov.au/registration/downloads/vsi09_rev4.pdf

Haven't I seen a grenn Baja with papers saying it can run larger wheels that was built by you ??

Ben,

In QLD only blue plates are done by engineers. Mod papers are done by queensland transport themselves.

My mod papers were done by Queensland Transport, and say 15x6 and 15x8, and they have no problem with the tyres I am running. So it has nothing to do with a single engineers interpretation.

When I put the V6 in I had to take it to the inspection station to have the engine number cited, and they didn't care about the tyres or anything else.

That is the problem with the rules. They are so fussy and badly written in QLD that the transport department themselves don't understand them.

The rules are being rewritten australia wide, and not just for the RTA. The last draft I read had a clause stating any size tyres can be run is the suspension and body is suitably modified. Let's hope that clause stays in the final version.