Thinking about purchasing set of 18" mags but I understand you need an Engineers Certificate if you go over two sizes up from factory how do i get one ?

There are plenty of folks on here that have 18 inch and larger rims here that haven't obtained an engineers certificate my friend.

There are plenty of folks on here that have 18 inch and larger rims here that haven't obtained an engineers certificate my friend.
Yes, they're riding around illegally.

18" rims should be fine if your car came with 16's standard. If it came with 15's then 17's is the biggest you can go and you will need an engineers certificate if you want 18's or bigger.

It's the overall diameter of the wheel & tyre which must remain within 2" of manufacturers specification. Not the diameter of the rim itself.

You can fit 20's and still be within 2" of the rolling diameter of the factory 15" wheels with std profile tyres.

However - each state is slightly different, so check with your local motoring authority to make sure.

It's the overall diameter of the wheel & tyre which must remain within 2" of manufacturers specification. Not the diameter of the rim itself.

You can fit 20's and still be within 2" of the rolling diameter of the factory 15" wheels with std profile tyres.

However - each state is slightly different, so check with your local motoring authority to make sure.

Not in SA it aint. In SA, its 2" upsize max and 1" width max from largest optioned wheel
for the vehicle. Why limit width to max of 1" increase/decrease, because offset cannot be
changed by more than 1" and the need to keep the wheels/tyres inside the wheel arch and
also not fowling the suspension arms.

I was told the rim size itself cannot be made larger then 2", doesn't matter about overall diamater.
Anywhay just go to the wreckers and get a VRX tyre plate from inside the drivers door and if cops ask say look it came standard with 17"s :badgrin:

lol we all need to ring rego office in our state and find out the real story because i always thought it was 2" overall as in tyre and rim

I've heard from some police in NSW that you could only go 2inches larger from the largest optional rim available for that vechicle and that the size had to be listed on the placard.

lol we all need to ring rego office in our state and find out the real story because i always thought it was 2" overall as in tyre and rim

2" bigger overall is a lot. You'd need to adjust the tacho and speedo as well. Standard
size for a magna VRX say with 225/50R17 gives OD of 656.8mm. Going 2" bigger would give
an OD of 707.6mm. That's an increase of 7.7%. So if the needle says 100, you'd actually
be doing 107.7. There is a limit on the change of OD but its not 2". Its a percentage of the
stock OD and I think from memory, its 3%.

From what I've read, SA is the only state that still has the 2" wheel size limit. All other
states say that you can go how ever big but the offset can't change by 1" (which means
width can't change by 1") and OD remain within 3%. However, going bigger may not be
good with your insurer.

Just visit the state transports websites for more info (Vic roads, transports SA, etc etc)

The 2" RIM increase is an old rule that has been scrapped by the ADR, most states have updated their legislation to reflect this, SA musn't have.
The main rule here is not a 2" increase in RIM size, it's a 15mm in overall diameter (rim and tyre combo). This is for most states, SA must be different.

The 2" RIM increase is an old rule that has been scrapped by the ADR, most states have updated their legislation to reflect this, SA musn't have.
The main rule here is not a 2" increase in RIM size, it's a 15mm in overall diameter (rim and tyre combo). This is for most states, SA must be different.

Ok, just went to transport sa. Here is the section on wheels and tyres. My memory must be
fading. OD changes is 15mm And offest changes is 13mm to comply with track change of
26mm.

WHEELS AND TYRES
All wheels and tyres fitted must comply with the Road Traffic (Miscellaneous) Regulations 1999.
The main points to note are:-
(a) The wheel track must not be increased by more than 26mm beyond the maximum specified by the
vehicle manufacturer. Maximum allowable tracks for individual vehicle models can be obtained from
Transport SA. The wheel track is the distance measured across the vehicle from the centre-line of one
tyre to the centre-line of the other tyre on the same axle.
(b) The wheels and tyres must not foul the body, suspension or any part of the vehicle under any operating
conditions and must not project beyond the bodywork, when the wheels are in the straight ahead
position and viewed from above.
(c) It is recommended that the tyres fitted to an axle of a vehicle must be of the same carcass construction.
The tyre size designation of tyres fitted to an axle is required to be the same.
(d) The tyres fitted must be suitable for the rim. The tyre retailer should have information about matching
tyres and rims.
(e) The load rating of the tyres must be adequate for the vehicle. ADR 24 vehicles (manufactured on or
after 1/1/73) have this information listed on the tyre placard. The load rating of any tyre fitted must not
be less than lowest load rating listed on the placard. For vehicles manufactured before 1/1/73 the tyres
must have a load carrying capacity equal to or greater than those supplied as standard equipment by the
vehicle manufacturer.
(f) Spacers are not permitted between the hub and wheel (unless originally fitted by the manufacturer)
(g) If the wheels of a vehicle are retained by multiple nuts or set screws, not by splines and a single nut,
then the wheel nuts must match the tapered holes in the wheel and the nuts must be engaged for their
full depth of thread.
(h) Wheels that have been widened by inserting a spacer band are not permitted.
(i) Vehicles manufactured on or after 1 January 1973 (ADR 24) are not permitted to increase or decrease
the diameter of the wheel by more than 50 mm than the largest or smallest wheel listed on the tyre
placard.
(j) The overall diameter of a wheel and tyre fitted to a vehicle manufactured on or after 1 January 1973
(ADR 24) must not be more than 15 mm greater than the largest tyre size listed on the tyre placard and
not more than 15 mm less than the smallest tyre size listed on the placard. Specifications for overall
tyre diameters are listed in the Tyre and Rim Standards Manual, issued by the Tyre and Rim
Association of Australia.
(k) Vehicles manufactured prior to 1 January 1973 are not required to comply with (i) and (j) above
however consideration must be given to clearance of the tyres and wheels on suspension and body
components.
(l) Passenger cars manufactured on or after 1/7/88 must also comply with ADR 18/.. that stipulates that the
speedometer must indicate the actual vehicle speed, for all speeds above 40 kilometres per hour to an
accuracy of plus or minus 10 percent.
When selecting aftermarket wheel rims for a motor vehicle, ensure that the offset of the rim does not vary by
more than 13mm from the original rim fitted by the vehicle manufacturer. This will ensure that the wheel
track is not increased by more than 26mm beyond the maximum specified by the vehicle manufacturer.
Transport SA has a list of maximum allowable wheel tracks for a large variety of vehicles and can be consulted
to confirm if a wheel track is within acceptable limits.
Wheel rims fitted to passenger cars manufactured after 1st July 1985, which are not original equipment or an
original equipment replacement by the vehicle manufacturer must be indelibly marked with the wheels nominal
diameter, width and offset and with identification of the manufacturer of the wheel and the standard to which
the wheel was manufactured. This should be checked before the wheels are purchased.
Tyres fitted to a vehicle must have a tread pattern at least 1.5 millimetres deep on all parts of the tyre that
normally come into contact with the road surface. Tyres are manufactured with tread wear indicators that are
located in the tyre grooves in at least four points around the circumference of the tyre. If the tread wear
indicators are at the same level as the overall tread, or there is less than 1.5 millimetres of tread depth on the
tyre, then the tyre is considered to be illegal.
Tyres fitted to passenger cars may not be treated by recutting or re-grooving of the tread unless the tyre is
constructed to do so and marked as such.

stupid vic roads website pdf is not text but images so can't cut and paste. However,
here is the link (http://www.vicroads.vic.gov.au/NR/rdonlyres/CC48FC10-4D57-4F04-82E1-3BD72EF88340/0/VSI8.pdf).

For those in Victoria, take note of the second to last dot point about changing tracks.
Basically, for the magna, the track cannot be changed unless Mitsu specified it can. This
means that the offsets cannot be changed. So, for a VRX with 225/50R17 on 17x7 wheel
with 46+ offset. To go wider, you have to keep the same offset.

Ok so point i) states this 2" rule, which isn't stated in the vic roads rule book. Just make sure the document you got the SA rules off of is up to date. So if it is up to date, it really sucks a$$ to live in SA :P.

Ok so point i) states this 2" rule, which isn't stated in the vic roads rule book. Just make sure the document you got the SA rules off of is up to date. So if it is up to date, it really sucks a$$ to live in SA :P.

Yeah, but did you read my point about the VIC rules in regards to changing track. If you
get wider wheels with wider tyres, It has to have the same offset in-order to keep the
track the same which pretty much limits width to 8", especially for the AWD magna/veradas
which has rear suspension components very close to the tyres. When I fitted 7" rims to
mine, I changed the offset to 40+ which means the inside clearance remains the same and
the track is widened by 12mm. You can't do this in Vic.

Yeah, but did you read my point about the VIC rules in regards to changing track. If you
get wider wheels with wider tyres, It has to have the same offset in-order to keep the
track the same which pretty much limits width to 8", especially for the AWD magna/veradas
which has rear suspension components very close to the tyres. When I fitted 7" rims to
mine, I changed the offset to 40+ which means the inside clearance remains the same and
the track is widened by 12mm. You can't do this in Vic.
I thought the track can be increased by up to 25mm?

I thought the track can be increased by up to 25mm?

Magnas/Veradas are front wheel drive, has MacPherson strut front suspension and a
negative scrub radius setup, thus according to Vic Roads, track and hence offset cannot
be changed.