Tyres & rego inspection rules

[NightFlight]

Hi,

Just about to take the car in for the yearly rego inspection.

It's a front wheel drive, with a pair of 185/60-14R Sumitomo HTR200s on the front.

I bought them 18 months ago, and with just local driving we've done a total of just 6,290kms on them since then.

Despite that the outside 15mm of each tyre is quite worn. From 1mm to 0mm on the outside 15mm. The rest of the the tyre road surface and sidewalls are otherwise fine.

[bTW - sounds like a poor wheel alignment? Comments on the cause would be appreciated]

As for the upcoming inspection - given that the RTA rules state:

"For vehicles with a GVM 4.5 tonnes or less, a tyre must have a tread pattern around its circumference

that is at least 1.5mm deep across the entire surface which contacts the road."

Does this mean then:

1) the tyres are OK, as the outside 15mm is normally NOT in contact with the road (the tryes give excellent cornering still anyway)

or

2) Is this a grey area, open to how rule hungry the inspector feels that day.

or

3) The matter is simple, the tyres are toast, end of story, new pair for rego renewal, regardless of how good and new the Sumitomos were?

Edited December 9, 2010 by NightFlight

[Ronnyboy]

Might need to see pics..........

if the thread is less then 1.5 mm then it needs to be replaced.......

[NightFlight]

Might need to see pics..........

if the thread is less then 1.5 mm then it needs to be replaced.......

The wear extends 15mm from the outside of the tread. The rest of the tyre surface (that contacts the road) is as new.

Here is a photo of the worst affected tyre (passenger side).

The question is Do these 18 month old Sumitomos need to be trashed because of this 15mm outer tread wear?

[Ronnyboy]

The wear extends 15mm from the outside of the tread. The rest of the tyre surface (that contacts the road) is as new.

Here is a photo of the worst affected tyre (passenger side).

The question is Do these 18 month old Sumitomos need to be trashed because of this 15mm outer tread wear?

These are fine, might get away with these :)

You need wheel allignments as u mentioned earlier :)

[NightFlight]

The wear extends 15mm from the outside of the tread. The rest of the tyre surface (that contacts the road) is as new.

Here is a photo of the worst affected tyre (passenger side).

The question is Do these 18 month old Sumitomos need to be trashed because of this 15mm outer tread wear?

These are fine, might get away with these :)

You need wheel allignments as u mentioned earlier :)

Thanks for the vote of confidence Ronnyboy.

I've got clearer pics of both front tyres here. Looks like DS on left and PS on the right.

IF the question is safety, there is no question that these are safe, with the on road tread almost as good as new.

We'll see.

One thing for certain - it shows the need for regular wheel alignments. I had a 2nd one at the 6 month mark, but either that was faulty or a bump since took both (?) front wheels a tad off.

[Ozzcaddy]

I think you will find it will be up to the the person who does the inspection. If in doubt, he will most likely not pass it as he could lose his Inspection Station license, if you were stopped by authorities (Police or RTA). I would ask for his opinion first up before any filling out of paper work is done.

Definitely a wheel alignment is required. I would go back to where the tyres were fitted and wheel alignment done. A alignment was done?

[Buff Hamster]

I think your wheel alignment is off - Camber settings. Or you corner too hard :P

Edited December 10, 2010 by A Buff Hamster

[Hiro]

My rule of thumb is that if there is a wear indicator there, it's there for a reason. So if you are worn down to the wear indicators on a bit that doesn't "normally" contact the road (it's worn though, so it must have contacted at some stage though :P), you still need to change the tyres.

[chrisby]

I don't mean to jump into things here but I can pretty much guarantee that it is underinflation that has caused your problem. In my 3years as a fitter and my 2 year as wheel aligner at tyrepower iv never gone through a day without atleast 5 cases exactly like this. Check your pressures and if its under 34 psi that will be your problem

[Buff Hamster]

I don't mean to jump into things here but I can pretty much guarantee that it is underinflation that has caused your problem. In my 3years as a fitter and my 2 year as wheel aligner at tyrepower iv never gone through a day without atleast 5 cases exactly like this. Check your pressures and if its under 34 psi that will be your problem

Wouldn't the inside threads be also worn if it's under inflated?

[Hiro]

I don't mean to jump into things here but I can pretty much guarantee that it is underinflation that has caused your problem. In my 3years as a fitter and my 2 year as wheel aligner at tyrepower iv never gone through a day without atleast 5 cases exactly like this. Check your pressures and if its under 34 psi that will be your problem

Wouldn't the inside threads be also worn if it's under inflated?

Depends on how under-inflated it is. Lower pressures may still give relatively even wear across the tread, but they will give more roll in the sidewall and it is always the outside sidewall of the tyre that cops it (due to weight transfer in corners), so you would expect to see more on the outside on tyres with soft sidewalls and low pressures.

[NightFlight]

I don't mean to jump into things here but I can pretty much guarantee that it is underinflation that has caused your problem. In my 3years as a fitter and my 2 year as wheel aligner at tyrepower iv never gone through a day without atleast 5 cases exactly like this. Check your pressures and if its under 34 psi that will be your problem

Wouldn't the inside threads be also worn if it's under inflated?

Depends on how under-inflated it is. Lower pressures may still give relatively even wear across the tread, but they will give more roll in the sidewall and it is always the outside sidewall of the tyre that cops it (due to weight transfer in corners), so you would expect to see more on the outside on tyres with soft sidewalls and low pressures.

What would you say was the right PSI for city driving with these tyres then?

[Buff Hamster]

My Aurion has 38/34psi front/back setup i say for a corolla about 34/30psi front/back setup cold.

It's best if you play around with the tyre pressure to see what suits you best.

[Rolla Boy]

My thoughts exactly, under inflation is the cause of tyres wearing on the outer edges, especially on the front due to cornering forces on the sidewalls... I used to put 34psi in my AE92 tyres and that was always fine...

And your passenger side tyre would fail rego at my work... Hows your spare tyre??? If it's not worn down at all, change it before you go for your inspection and you'll be fine tyre wise, rego states you need a spare but as it's for emergency use only, it doesn't have to have tread...

[NightFlight]

Thanks for all the input guys.

I'm getting new tyres anyway just to be sure.

I ran the old ones at 30 PSI. I'll keep the new ones at 35.