Going Up a Tyre Size With 50mm Lift Already Installed

Submitted: Friday, Apr 20, 2018 at 11:16
ThreadID: 136587 Views:5325 Replies:8 FollowUps:15
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Hi, further to my thread about choice of A/T tyres, I thought I'd ask another question relating to lift and tyre size:

I had initially thought of going up from 265/65 to 265/70 as I already have a 50mm lift fitted and wouldn't mind filling the arches a bit more, along with the very slight increase in clearance.

I hear varying things relating to the legality of this. From looking around online, it seems to be the case that you can't lift the overall vehicle height more than 50mm without engineering certification.

Speaking to various tyre places when getting quotes, most said that the slight increase in tyre size wouldn't affect legality as in addition to the lift, you're allowed a slight increase in tyre size. I doubt this.

There are thousands and thousands of rigs in WA running larger tyres and suspension lifts and I'm sure only a very small percentage of them have engineering certification and the ones that do would be running huge mods. Is it really that much of an issue and will I have to worry about insurance paying out in the event of an accident if I go with the bigger rubber? I've heard a fair amount about people still getting payouts despite having lifts and larger rubber...

Also, would the small increase in tyre size realistically be of any benefit other than the fact that the arches would fill a bit more and make the car look a bit more serious? I don't know if this would actually be of any real benefit off road...

With the current deal that Bob Jane are doing on Hankook Dynapros right now, I could potentially get four 265/65 for $735 and use my best existing worn tyre as a spare, as opposed to spending $1370 on five of the of the 265/70/17...

Thanks in advance
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Reply By: Member - peter_mcc - Friday, Apr 20, 2018 at 11:28

Friday, Apr 20, 2018 at 11:28
This is from NSW - if you're in WA you might need to check what the local rules are.
(from http://www.rms.nsw.gov.au/documents/roads/registration/get-nsw-registration/light-vehicle-modifications-manual-suspension-and-ride-height.pdf page 10)

In addition to the above, the following are not considered to be significant modifications and do NOT require assessing or certification:
a. Except where specified below, modifications to the suspension that does not increase or decrease the vehicle’s ride height by more than 50mm.
b. Changes in the diameter of the wheel and tyre combination of up to +/- 7% of the largest size specified by the vehicle manufacturer.
c. Modifications to the ride height up to 75mm that incorporate a maximum change in the suspension of 50mm, and/or an increase in the diameter of the wheel and tyre
combination of up to 50mm

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Follow Up By: Donlogan - Friday, Apr 20, 2018 at 11:47

Friday, Apr 20, 2018 at 11:47
Thanks. I hope that's the case in WA. If not then i'm sure we'll catch up in around 20 years time...
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Follow Up By: Kenell - Friday, Apr 20, 2018 at 13:04

Friday, Apr 20, 2018 at 13:04
Very similar in Vic - almost identical in fact. Main exception being in b. where NSW states +/- 7% Vic says 15mm.
Research the WA legislation to be certain I guess.
I have run 75 profiles on my last 2 vehicles after replacing original tyres that were 70. I also run with a 50mm lift - not because I particularly wanted the lift but that is what comes with the suspension upgrades. I have found that the speedo reads accurately with the higher profile which is a side benefit but the main reason I do it is for ride. In a 76 series with leaf springs in the back you need all the cushioning you can get !!
If you do your research I think you will find you will be OK.

Ken
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Reply By: Munji - Friday, Apr 20, 2018 at 11:52

Friday, Apr 20, 2018 at 11:52
Be mindful that there are a lot of vehicles out on the roads that are not compliant regarding suspensions and ride heights but one needs to be aware that these people travel around thinking that because they have passed a patrol car without being stopped all is good.
Let me say that if your vehicle is involved in a crash whereby someone is seriously injured or killed then your vehicle will be examined and any mods above what is allowed will be seriously looked at and may result in charges being laid against you.
Therefore one needs to consider what mods are acceptable in whatever state they intend to traverse.
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Follow Up By: Member - nick b boab - Friday, Apr 20, 2018 at 20:45

Friday, Apr 20, 2018 at 20:45
Good comment : this is exactly what the police were chanting at the caravan and camping show few years back . It's all fine to the s*** hits the fan....
As I understand in most States you're allowed a 15 mm increase standard size.....
Cheers Nick b

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Reply By: Member - Bigfish - Friday, Apr 20, 2018 at 13:34

Friday, Apr 20, 2018 at 13:34
Stay with the standard size. Cheaper and easier to get hold of. The increase is not worth an extra dollar by going up a size. The bigger tyre is better mentality is a load of garbage for 90% of people.
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Follow Up By: RMD - Friday, Apr 20, 2018 at 13:48

Friday, Apr 20, 2018 at 13:48
He wants to fill out the guards. What for I wonder? The vehicle doesn't have an identity crisis or deficiency complex. Bigger tyre dia means less fuel economy, less towing and braking ability too. There are a lot of sheep out there.
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Follow Up By: AlbyNSW - Friday, Apr 20, 2018 at 19:11

Friday, Apr 20, 2018 at 19:11
Some people ( most) do modifications for cosmetic reasons as well.
There is nothing wrong with that.
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Follow Up By: RMD - Saturday, Apr 21, 2018 at 13:48

Saturday, Apr 21, 2018 at 13:48
Alby
I supose that is like Botox for 4WD's, pouting, puffed up and perfect?
Max Factor should do some products for offroad blokes then.
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Follow Up By: AlbyNSW - Saturday, Apr 21, 2018 at 18:01

Saturday, Apr 21, 2018 at 18:01
RMD I guess beauty is in the eyes of the beholder.
Not everyone likes the look of some of the modern vehicles with their wheelbarrow size wheels, if you do that is fine but we are not all the same and can understand the OP wanting his vehicle to look in proportion with its new stance.
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Follow Up By: Member Kerry W (WA) - Tuesday, Apr 24, 2018 at 12:33

Tuesday, Apr 24, 2018 at 12:33
Depends on the primary use of the vehicle.
Kerry W (Qld)
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Reply By: Jackolux - Friday, Apr 20, 2018 at 16:59

Friday, Apr 20, 2018 at 16:59
One inch / 25mm and a extra $630 , sounds like a great idea , you will have a whopping 1/2 inch extra ground clearance and it will look tougher , I don't think .
But who cares what others think do what you are happy with .
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Reply By: swampy - Friday, Apr 20, 2018 at 17:12

Friday, Apr 20, 2018 at 17:12
Hi
get slightly bigger but not bigger in a HUGE sense.
Speedo and pulling power will be reduced in heavy mud or sand if u go over the top .
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Reply By: splits - Friday, Apr 20, 2018 at 21:25

Friday, Apr 20, 2018 at 21:25
I had initially thought of going up from 265/65 to 265/70 as I already have a 50mm lift fitted and wouldn't mind filling the arches a bit more, along with the very slight increase in clearance.
-----------------------------------------------------------

There is a bit more to tyres and their pressures than just filling the arches and looking good. This video and the series that follow it gives you a brief insight into the role they play, and other things play, in how the car handles.Slip Angles.

The tyres are all that is holding your car onto the road and they are not something to be fiddled with unless you know exactly what you are doing.

We have plenty of cars on the road with lifted suspensions plus whatever tyres and pressures the owner thinks is best. Then there is raised centres of gravity; rear suspension leaf springs or linkage operating at the wrong angles to assist it cornering stability through their roll steer feature; excessive rear end weight; rear air bags and brand X aftermarket shocks. Who knows what the cars are going to do in an emergency situation. Then there is the roll bar or bars. Few if any 4wd owners even think about them.

Back in the 1980s when Peter Brock modified a few Ford Mavericks (Nissan Patrols) he designed a new sway bar to remove all trace of oversteer because the average driver can not handle it. He did know a thing or two about suspensions and obviously had road safety in mind. I doubt if the same could be said about many 4x4 suspension companies
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Follow Up By: 76lifted - Saturday, Apr 21, 2018 at 13:12

Saturday, Apr 21, 2018 at 13:12
I am not very experienced but i just about garuantee understeer is worse ?

Also how does a swaybar affect oversteer ? Body roll maybe......

From my limited experience bigger tyres do help in mud. Think a vdj76 with 33's vs a vdj76 with 35's ya will never guess who didnt get stuck on the hard ruts

Cheers jed

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Follow Up By: splits - Saturday, Apr 21, 2018 at 21:26

Saturday, Apr 21, 2018 at 21:26
Also how does a swaybar affect oversteer ? Body roll maybe......
-------------------------------------------------------------------------
Sway bars can increase the load on the outside tyres in corners or reduce it. They transfer weight from side to side by lifting the inside wheel a little or a lot depending on what the engineers want.

Look through the charts mixed in with the photos on this page. It is not just sway bars that affect oversteer or understeer.
Understeer/Oversteer

There is nothing new in those charts. All of that information has been known and used by suspension engineers for maybe as far back as the late 1940s. They have been designing their cars to understeer for who knows how long. It is easy to see how suspension changes made to improve off road performance can completely stuff up on road handling, particularly in emergency situations.

I hope you are trying out your 33s and 35s in mud on private property. There are far too many closed tracks around the country thanks to idiots who spend all week doing rain dances so they can rip wet tracks to pieces on weekends.
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Reply By: Blown4by - Saturday, Apr 21, 2018 at 12:29

Saturday, Apr 21, 2018 at 12:29
Speaking to various tyre places when getting quotes, most said that the slight increase in tyre size wouldn't affect legality as in addition to the lift, you're allowed a slight increase in tyre size. I doubt this
You are absolutely correct in doubting this because the tyre shop is wrong. Many 4WD suppliers (including window tint applicators) will tell customers what they want to hear to get a sale. There are also some that are principled and when legislation allows liability to go back up the line to include the installers and sellers of items that make vehicles illegal not much is going to change.
Rest assured in WA, having adopted VSB14, body lift, suspension lift and tyre lift are all included in the 50mm total lift allowed without certification. However to be legal a DOT vehicle examination and issue of a Modification Permit is still required in WA and you are advised to let your insurer know. I would expect that all jurisdictions in AUS that are signatories to VSB14 would have the same rules although some may have policies that vary some sections slightly. Be careful listening to people who read one line in isolation in legislation that suits what they want to hear. You need to do your own research and read the legislation covering the topic in its entirety. Appended below is what VSB14 says about the 50mm suspension lift on 4WD's without certification and tyre diameter increases on 4WD's. Bear in mind what is stated as being allowed is also subject to vehicle track, ESP, clearance between the tyres and body parts during full suspension and steering travel, etc, etc.


I hope this answers your questions
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Follow Up By: Idler Chris - Saturday, Apr 21, 2018 at 14:51

Saturday, Apr 21, 2018 at 14:51
Am I missing something here?

Blown4by you say "Modification Permit is still required in WA and you are advised to let your insurer know."
I do not see any reference to a "Modification Permit" in the sections of VSB14 that you have quoted.

You show paragraph 4.11 where it says, "Raising the height of the vehicle maybe performed without certification providing the overall increase in vehicle height is not more than 50mm." appears to be at odds with your claim that it does require certification. Something seems to be missing.

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Follow Up By: Blown4by - Sunday, Apr 22, 2018 at 10:02

Sunday, Apr 22, 2018 at 10:02
Idler Chris: Nothing is missing from my post. VSB14 is a National (DIRD&C) document and as such does not cover any additional requirements imposed by individual jurisdictions. See insert below. "Certification" refers to Engineering Certification and as the document states: "No certification is required for 4WD height increases up to 50mm"
In WA however separate State legislation requires that certain vehicle modifications require an examination by a DOT/AIS Authorised Vehicle Examiner who subsequent to a satisfactory result will then issue a Modification Permit for that modification. See insert below. The details covered by the Modification Permit would then be entered in to the WA Licensing database (TRELIS) This shows that the DOT has approved the modification and should the person be stopped by the Police the Mod Permit can be shown to the Officers as evidence that the particular modification has been examined and approved for use on roads. This however does not preclude the Police from issuing a Defect Notice should they feel the modification is not compliant. For example if, subsequent to the Mod Permit being issued the vehicle owner, as often happens, has raised the vehicle further than 50mm by either suspension lift, body lift, larger diameter tyres or the use of extended spring shackles which are non-compliant. I agree VSB14 does not state insurers have to be notified however I can assure you they do want to be told about suspension height increases due to the additional roll over risk resulting from the vehicles higher centre of gravity. Most will not insure a modified vehicle in WA unless a DOT Mod permit has been issued due to the increased risk and it is the law. After an accident, as well as checking that the vehicle is roadworthy insurance assessors (always ready to find a reason to deny a claim) will check for any vehicle modifications. The following is from the DIRD&C webpage re VSB14.

WA Road Traffic (Vehicles) Regulations Reg. 235 Alteration to Vehicles



If you want to read more this is the link to the WA DOT Licensing webpage re Modification Permits being required.
WA Department of Transport Licensing webpage re Modification Permits

I hope this information fulfills the apparent 'missing link'. Pun intended:-)
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Reply By: nickb - Saturday, Apr 21, 2018 at 17:07

Saturday, Apr 21, 2018 at 17:07
Just go the slightly bigger tyres. Technically it may be illegal. In reality it won’t affect anything regarding insurance etc. If anyone can verify where going up a tyre size has had their insurance voided or charges laid please share. Each time I bring this up no one ever can.

It’s the same as doing 61in a 60 zone. Yes it’s is technically illegal but no one cares, nor will they ever. Again if you have proof otherwise please share.

One other thing to check the the manufacturers actual tyre diameter. 265/65/17 in one brand may be taller than another brand.
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Follow Up By: Michael H9 - Thursday, Apr 26, 2018 at 06:51

Thursday, Apr 26, 2018 at 06:51
I think they do care about doing 61 in a 60 zone in Victoria. I heard they have a zero tolerance policy, not that it helps their road toll at all.
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Follow Up By: nickb - Thursday, Apr 26, 2018 at 12:26

Thursday, Apr 26, 2018 at 12:26
Sort of. They will book you at 63kph, then they deduct 2kph for accuracy(or tolerance) and make it 61kph.
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Follow Up By: Gramps - Thursday, Apr 26, 2018 at 15:16

Thursday, Apr 26, 2018 at 15:16
Still have'nt seen any evidence of anyone being booked for actual 61kph or nominal as per nickb above. All anecdotal so far.

Regards
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