Legality 31x10.5 + Lift, specifically TJ and Victoria - AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand

Murchison Products
Find out how to advertise on Ausjeep?

Go Back   AUSJEEPOFFROAD.COM Jeep News Australia and New Zealand > JEEP GARAGE > TJ / YJ / Brute Wrangler


Portal Register Forums Trading Your Jeep New Garage Mark All Read

Post New Thread  Reply
 
Thread Tools Search this Thread
  #1  
Old 4 Days Ago
ajftj's Avatar
ajftj  ajftj is offline
AJOR Gold
 
Join Date: Jun 2017
Location: Geelong
Posts: 71
What Jeep do I drive?: TJ
Likes: 3
Liked 5 Times in 5 Posts
Question Legality 31x10.5 + Lift, specifically TJ and Victoria

Started a new thread as 2" lift and 31x10.5 is a popular combination and didn't want to hi-jack or get confused with all the other lift and tyre combinations.
And I made a couple of mistakes in my previous.

First the lift kit, then the tyre discussion.

I think Victoria is allowed 50mm lift + 25mm tyre lift without Engineering.
I looked up these TJ vehicle details at http://myrta.com/rvd/searchRVD.do

Standard TJ 2003
P225/75R15 with +32mm Rim offset, Wheel track Front and Rear 1473mm
Unladen vertical measurement wheel centre to top of wheel arch.
Front 455mm, Rear 485mm

I bought my Jeep with a 2" lift detailed.
My Jeep measures 540mm wheel centre to arch.

If I focus on the front 540-455=85mm that was not a 2" lift kit, more like 3.5"

So at this point I blow the 50+25=75mm and already need Engineering.

Then I considered lowering to get back under 75mm.
As I read a bit it seems the max wheel center to arch increase is 2" 50mm.
And the max tyre increase is 25mm.

So I worked out the 31x10.5 increase for interest.

Stock rim = 15 inch = 381mm (rim only)
31x10.5 = 31 inch = 787.4mm (whole wheel and tyre diameter)
787.4-381= 406.4mm this is the two sidewalls of the 31x10.5 tyre
406.4/2 = 203.2 mm this is one sidewall of the 31x10.5
Stock tyre = 225x75 = 168.75 one sidewall

Stock tyre one sidewall - 31x10.5 tyre one sidewall = 203.2-168.75= 34.45mm

Did I do this wrong? Can't see how a 31x10.5 would ever be allowed in Vic??
It exceeds the 25mm allowable tyre lift.

And.. My Jeep would be a total increase of 85mm body + 34.45 tyre = approx 120mm total lift

So HELP... any informed answers would be appreciated.

Is the 50 lift +25 tyre lift without engineering correct?
Can I actually get 120mm Engineered?
What level of Engineering is this - a static inspection or the full swerve test?
Are 31x10.5 tyres ever actually legal on their own or even possible to engineer on a TJ?

All only in Victoria.
__________________
2004 TJ, 4.0L, Manual, $2K spent on maintenance in year 1 and rising 😀

Sponsored Posts
  #2  
Old 4 Days Ago
ren0vator's Avatar
ren0vator  ren0vator is offline
Established Member
 
Join Date: Dec 2015
Location: Townsville
Posts: 468
What Jeep do I drive?: WH
Likes: 112
Liked 113 Times in 81 Posts
Check out my Ride(s)
Default

Hey ajftj,

All state modifcation laws are based on NCOP
(National Code of Practice for Modifying Light Vehicles)
This is better know as Vehicle Standards Bulletin 14

VSB14 can be downloaded here
Just a matter of searching Vic Roads website for your local interpretation

In particular you will need to understand LS7 - LS9
Cheers
__________________
Life's Too Short To Drive A Toyota
  #3  
Old 4 Days Ago
Struth's Avatar
Struth  Struth is offline
CrawlerStar
 
Join Date: Jul 2015
Location: Melbourne, Australia
Posts: 255
What Jeep do I drive?: TJ
Likes: 44
Liked 60 Times in 39 Posts
Default

Quote:
Originally Posted by ajftj View Post
Did I do this wrong? Can't see how a 31x10.5 would ever be allowed in Vic??
It exceeds the 25mm allowable tyre lift.

And.. My Jeep would be a total increase of 85mm body + 34.45 tyre = approx 120mm total lift

Is the 50 lift +25 tyre lift without engineering correct?
Can I actually get 120mm Engineered?
What level of Engineering is this - a static inspection or the full swerve test?
Are 31x10.5 tyres ever actually legal on their own or even possible to engineer on a TJ?

All only in Victoria.
Technically speaking, no, you cant run 31 inch tires on a TJ because a LT225/75R15 = 28-1/2 so this would mean you can only go two sizes bigger to a 30-1/2.

It's easy to see how it's up for interpretation when a 31" tire actually measures about 30-1/2, nevertheless,
as I understand it, the popo only allow you to fit two sizes up from the largest size displayed on the place card inside the passenger door jamb.
A quick check of the size displayed on the sidewall and unless you have a blue sticker that's been passed by a Vic roads inspector that says otherwise, the popo let the canary out of the cage.

Another ridiculous law for the nanny capital of the world, but nice post, you've managed to articulate a relevant and pressing issue for many Australian TJ owners, well done.
__________________
F'n Great Forest national park threatens 4WheelDrive access, select "4WheelDriving" and "SUBMIT"
  #4  
Old 4 Days Ago
bonza's Avatar
bonza  bonza is offline
RubiconSlammer
 
Join Date: Mar 2006
Location: Melbourne
Posts: 1,487
What Jeep do I drive?: TJ
Likes: 49
Liked 77 Times in 64 Posts
Default

Quote:
Originally Posted by Struth View Post
Technically speaking, no, you cant run 31 inch tires on a TJ because a LT225/75R15 = 28-1/2 so this would mean you can only go two sizes bigger to a 30-1/2.
yes, unfortunately this does seem to be correct

BFG list their 225/75R15 at 722mm dia
and their 31x10.5R15 are 775mm dia being 53mm or 26.5mm lift

this is a good example of what happens when idiot pen pushing non technical minded bureaucrats make technical decisions

I'm also at the ridiculous situation with my 70 series LandCruiser

the lower spec Workmate comes with skinny tyres the equivalent to 33" diameter. my GXL comes the wider but smaller diameter to the equivalent to 30.8" diameter. Legally I cannot upgrade to the same diameter as what is on the Workmate event though except for cosmetics, they are the same
__________________
05 six speed khaki renegade
I like a man who grins when he fights—
Winston Churchill
Sponsored Posts
  #5  
Old 3 Days Ago
ajftj's Avatar
ajftj  ajftj is offline
AJOR Gold
 
Join Date: Jun 2017
Location: Geelong
Posts: 71
What Jeep do I drive?: TJ
Likes: 3
Liked 5 Times in 5 Posts
Default

ren0vator - thanks for the link to VSB14, I read it, it's very clear, and a little depressing, but at least I know.

Struth, bonza - always good to get some feedback on here and you are both pretty active contributors, even confirming what I thought, unfortunately - thanks all the same.

I don't really want any Police attention and I kind of like the idea of being insured. I do wonder after the dust has settled in QLD whether VIC will have a little go too. We do like our rules down here, and there are quire a few people who don't like 4WD activity.

So in summary for the record..

Is the 50 lift +25 tyre lift without engineering correct? [Yep - Afraid so]
Can I actually get 120mm Engineered? [Yep - but probably not worth the $ for the % serious offroad use I do]
What level of Engineering is this - a static inspection or the full swerve test?
[Full dynamic test]
Are 31x10.5 tyres ever actually legal on their own or even possible to engineer on a TJ?
[Not legal]

I was planning on some new tyres this year, so I guess I will go with something that is within the limits, but probably go for actual muddies rather than the existing slippery AT's.

New springs around $400 for a 2" set of 4. Might be able to recover a bit of cost on the existing set second hand as they were from DBOR and give a genuine 3.5".

Guess i'm going a bit soft.
AusJeepOffroad please don't disown me.
__________________
2004 TJ, 4.0L, Manual, $2K spent on maintenance in year 1 and rising 😀
Likes: (1)
  #6  
Old 2 Days Ago
Struth's Avatar
Struth  Struth is offline
CrawlerStar
 
Join Date: Jul 2015
Location: Melbourne, Australia
Posts: 255
What Jeep do I drive?: TJ
Likes: 44
Liked 60 Times in 39 Posts
Default

NP ajftj,

Almost all the popo down here are pretty decent blokes/chicks and wouldent give a TJ with 31's a second look, provided nothing sticks outside the guards, your running a OEM or an ADR approved front bar and no looking for attention.

You could run two sets of wheels and change them over when you feel the heat. Also worth considering...

Option 1
Subtract the lift height of the 31" tires you want to run from 75 mill and try to bump stop and grind your way there with your lift, add some heavy bars/racks, whatever it takes. If you can make that work you can get an engineer to sign off on the tires without a swerve test, typically about $600 bucks if you do all the work and show the proof of the OEM specification against your modification.

Option 2
Take out finance, spent ten or so on a 33" engineered setup.
__________________
F'n Great Forest national park threatens 4WheelDrive access, select "4WheelDriving" and "SUBMIT"

Last edited by Struth; 2 Days Ago at 06:09 PM.
Sponsored Posts
  #7  
Old 2 Days Ago
bonza's Avatar
bonza  bonza is offline
RubiconSlammer
 
Join Date: Mar 2006
Location: Melbourne
Posts: 1,487
What Jeep do I drive?: TJ
Likes: 49
Liked 77 Times in 64 Posts
Default

for the record I run 31" BFG muddies and a 45mm lift, thus giving me just under 75mm total

stock front bar with all the plastic bits removed and a winch bolted to a winch plate

never been hassled by the cops or questioned over the past 12 years with this setup
__________________
05 six speed khaki renegade
I like a man who grins when he fights—
Winston Churchill
Likes: (1)
Post New Thread  Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On


» Advertisements_AS2




Powered by vBadvanced CMPS v3.2.3



All times are GMT +10. The time now is 04:09 AM.




AJOR does not vouch for or warrant the accuracy, completeness or usefulness of any message, and are not responsible for the contents of any message. The messages express the views of the author of the message, not necessarily the views of AJOR or any entity associated with AJOR, nor should any advice be substituted as technical advice replacing that of a mechanic. You agree, through your use of this service, that you will not use AJOR to post any material which is knowingly false and/or defamatory, inaccurate, abusive, vulgar, hateful, harassing, obscene, profane, sexually oriented, threatening, invasive of a person's privacy, religious, political or otherwise violative of any law. You agree not to post any copyrighted material unless the copyright is owned by you or by AJOR. The owner, administrators and moderators of AJOR reserve the right to delete any message or members for any or no reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold harmless AJOR, the administrators, moderators, and their agents with respect to any claim based upon transmission of your message(s). The use of profile signatures to intentionally mislead or misdirect any member on this forum is not acceptable and may result in your account being suspended. Any trip that is organised through the AJOR forum is participated at your own risk. If you or your vehicle is damaged it is your responsibility, not that of the person that posted the thread, message or topic initiating the trip, nor the organisers of AJOR or moderators of any specific forum. This forum and associated website is the property of AJOR.





Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

AJOR © 2002 - 2018 AUSJEEPOFFROAD.COM. All corporate trademarked names and logos are property of their respective owners. Ausjeepoffroad is in no way associated with DaimlerChrysler Corporation or Fiat Jeep.
www.midlifemate.com wayalife.com jkwrangler.com ausjeepforum.com jk-forum.com canadianjeepoffroad.com cryptoprofitcalculator.net
vB Ad Management by =RedTyger=