tyre certification

[scotty36]

Hi all

Has anyone had to certify there tyres . I know you have to certify rims but what about tyres? I have a safari with 315x75 16 can any one put some light on this for me. Thank you all.

[Sadam_Husain]

the last time I looked at the LV stuff you had to certify for any change 5% +/- of the origional tyre diameter the vehicle was fitted with by the manufacturer

[scotty36]

yes know that but i have not see tyre size on my certificaton plate or on anyone that i have seen . when the safari was done for the 16x8 it had 285/75x16 that 5% more then

[kiwipete]

When I had my truck certed, they said it was only the rims that are certed, tyre size diddnt come into it.
I currently run 15x7 rims with 31's but am certed for 15x8's and had 33's on it when certed.
The plate only mentions 15x8 for rim sizes.

[scotty36]

thats what i think but went to get wfo and was tall that he not shore after going there 2 time before with the some tyre

[wjw]

thats what i think but went to get wfo and was tall that he not shore after going there 2 time before with the some tyre

I was told the tyre size is on the documentation at LTNZ.

[darinz]

I have tyre size on my LVV cert plate. I have also had speedo calibrated to suit so with beadlocked 35x11.5 Simex it is 100% road legal.

[scotty36]

may have to look at that. What did the calibrated cost

[KiwiBacon]

thats what i think but went to get wfo and was tall that he not shore after going there 2 time before with the some tyre

I was told the tyre size is on the documentation at LTNZ.

Yes it is. No problem to look up and see what the stock tyre size is. Really if it's beyond 5% over it's usually quite obvious.

[yorick]

I was told the tyre size is on the documentation at LTNZ.

Yes it is. No problem to look up and see what the stock tyre size is. Really if it's beyond 5% over it's usually quite obvious.

The 5% is to do with rolling circumference. So if you have a 31" tire as standard your rolling circumference will be about 97.4 inches. Upsizing to 33" will take you to around 103.7 or a 6.45 percent increase. It would have to be certified. The reasoning behind it is to do with body interference and Speedo accuracy. So my Paj would be good on the former and be out on the latter.

If anyone wants I'll send them an OpenOffice spreadsheet that you just have to input yer tyre info before and after and it'll tell you the percentage.

[yorick]

yes know that but i have not see tyre size on my certificaton plate or on anyone that i have seen . when the safari was done for the 16x8 it had 285/75x16 that 5% more then

Hey Scotty,
Sorry to say, even from 285 to 315 needs certing

[BJ71]

I had my vehicle certed recently with 285/75-16 and requested that the tyre but put on. Was told that they could not put tyre on and only rim would be certed.

i argued the issue with tyre size and the 5% thresehold for warrants and whilst the certifier agreed he said it was the issuing office in wellington that put the info on the plate and as there was no specific space on the plate tyre size wouldn't go on. the interesting thing was that the certifier was being audited and it happened to be my vehicle (they were very thorough), so i also had the same discussion with the auditor and got the same response.

So i don't have the tyre size on my plate.

It appears that there are some inconsistancies around the country on this (and other issues). So it might pay to go to Darinz certifier

[yorick]

It appears that there are some inconsistancies around the country on this (and other issues). So it might pay to go to Darinz certifier

I got mine done last week, the only thing to be done in fact was the Tyre Circumference/speedo recal thing. Done and dusted in no time. He even gave me a discount on the fee because of how easy it was.

Methinks you have some pedantic idiots down that way. My guy wasn't 100% sure, so rang LVVTA to confirm things as well.

Moral: get yer Cert done in the North Island!

[wjw]

It appears that there are some inconsistancies around the country on this (and other issues). So it might pay to go to Darinz certifier

I got mine done last week, the only thing to be done in fact was the Tyre Circumference/speedo recal thing. Done and dusted in no time. He even gave me a discount on the fee because of how easy it was.

Methinks you have some pedantic idiots down that way. My guy wasn't 100% sure, so rang LVVTA to confirm things as well.

Moral: get yer Cert done in the North Island!

But remember your vehicle is not in a warrantable condition unless (tyres":

"have an outer circumference that is no more than 5% greater than OE."

If you have a cert, the tyre size is logged on the system and OE is then replaced with your tyre size at cert time. So if you have the wrong tyres at WOF time you vehicle could fail. Also if you have an accident with different size tyres on your vehicle, it is technically, not in warrantable condition, which gives your insurance company an excuse not to pay out.

[yorick]

But remember your vehicle is not in a warrantable condition unless (tyres":

"have an outer circumference that is no more than 5% greater than OE."

'Scuse Bill. The above makes no sense. The rules state that there should be no variation from Original rolling circumference greater than 5%. Variation That means both bigger or smaller. What the new rule says is: If there IS such a variation, then that needs to be certified A) To check for body/ground clearance and B) for Speedometer Calibration

If you have a cert, the tyre size is logged on the system and OE is then replaced with your tyre size at cert time.

Correct

So if you have the wrong tyres at WOF time you vehicle could fail.

To clarify: The Vehicle's tyre size was originally certified at VIN time. If that vehicle has now been certified for a non-original tyre size, then at warrant time the vehicle must be wearing tyres that do not vary more than 5% from that certified size. The original size in the vin has been superceded by the later certification.

[badnuz]

i asked my local cert guy about rims and tires, he told me my std ( albeit fully recond) cruiser brakes would fail cert with my 35's on ( in the repeat brake test) so i was told to bring it in on my road tires ... but that isnt what im wanting... to get certed with 35's would then mean its technically " not up to wof std " if im using my road tires! do i need to get 35' all terrains ( or a tire within 5%) on 15x8 rims so everything stays the same??

[wjw]

"have an outer circumference that is no more than 5% greater than OE."

This bit is actually from the warrent book.

[jumper]

I spoke to the certifier in wellington about getting some bits done, he said tyres are not certed only wheels but i could get two sets of wheels certed. Beadlocks have to be 36 bolt to get certed.

[MNC]

i asked my local cert guy about rims and tires, he told me my std ( albeit fully recond) cruiser brakes would fail cert with my 35's on ( in the repeat brake test) so i was told to bring it in on my road tires ... but that isnt what im wanting... to get certed with 35's would then mean its technically " not up to wof std " if im using my road tires! do i need to get 35' all terrains ( or a tire within 5%) on 15x8 rims so everything stays the same??

What he is saving is that your standard brakes aren`t up to stopping the truck (to WOF standards) if running 35" tyres (better check he is actually right on this - have you tried the repeat brake test running 35s?). If he is correct you need to either:
1) run the factory size tyres (or try a size between factory and 35"s if failing on 35"s), which the factory brakes will be able to satisfy the repeat brake test,
2) Upgrade your factory brakes to some more powerful units to satisfy the Certification and repeat brake test.

[badnuz]

im yet to try the brake test ( only just got damn thing running yest)... but even if it does pass with the 35's when im just dricing round on my road tires ( 31's on 15x7s) then i wil be potentially be not covered with ins because its certed to run bigger.... im confused! maybe just buy a trailer and only use the 35's off road..... but then i still wont be covered for ins cause the cert plate will be for 31's!!!!!!!!! hmmmmmmm

[haynzy]

I asked the guy doing my certification yesterday about tyre size and he said only the rim size goes on the cert plate, plus 31x10.5s are within the 5% over ome

[MNC]

im yet to try the brake test ( only just got damn thing running yest)... but even if it does pass with the 35's when im just dricing round on my road tires ( 31's on 15x7s) then i wil be potentially be not covered with ins because its certed to run bigger.... im confused! maybe just buy a trailer and only use the 35's off road..... but then i still wont be covered for ins cause the cert plate will be for 31's!!!!!!!!! hmmmmmmm

You need to decide if you want to run 31s or 35s (both on and off road).

If you want a separate set of Road & Mud tyres then get both in the same size (ie both in 31s or both in 35s) and if you go with 35s (both on and off road then get it certed for them). Hope that makes sense to you.

Would be cheaper to buy a second hand set of 35x12.5x15 ATs than buying a trailer (and a tow wagon).

Just my 2c's

[BJ71]

Just to be a bit of a devils advocate here, but the WOF cade says GREATER THAN 5%, It does not mention SMALLER THAN.

Therefore what is wrong with a smaller tyre, The basis of certification is basically that you can make anything worse tha OEM. If you run smaller tyres your braking would be better and you would travel slower (speedo reads high). I can't see the problem unless you start breaking other rules like 100mm clearance which is most unlikely given the vehicles we tend to drive.

This whole issue is very important to us 4WDers as it affects our back pocket whhen it come to insurance etc, perhaps the should be refered to the nzfwda to be discussed at the LVVTA and clarification provided, the nzfwda is after all a member of that group?