Hugely excessive tyre wear?

metropolis986 · Nov 1, 2011

I am flabbergasted as today I had my OPC major service for my 986 only to be informed that my rear tyres are approximately down to 3mm.

These tyres (Michelin Pilot Sports) were (along with the fronts) replaced .... on the 20th of September?!?! The dealership did say the tracking was off (I can't remember by how much now as it's not in the paperwork they gave me, they did however tell me) but even so I have only done 700 miles of mostly urban driving. No track day or anything of the sort...

I am hugely disappointed and perplexed as why quality tyres would basically go down so much in less than a month and a half. I suppose it'll teach me a lesson to get things like this done at KwikFit in the future (who clearly have no idea what they are doing!!) but even so it can't possibly be the only reason right? This is monumental tyre wear from my (limited) experience. I will get the alignment corrected immediately, is there however something else that could be wrong here?

I think the OPC didn't even believe I had the tires changed in late September.

BrianJ · Nov 2, 2011

The Pilot Sports on the rear of my 986 used to last 19k miles (3 sets). Assuming they were 6mm when new and not somebody else's summer tyres they had just removed, I can't imagine how they wore 3mm in 700 miles, unless the OPC measured them incorrectly, or you have some other problem which presumably the OPC would have spotted. Have you measured them yourself? My own experience of Kwik Fit has always been excellent, though I have never usd them for geometry.

Buddy · Nov 2, 2011

I take it that you haven't had a full alignment done on the suspension. Check with your region members for a good 4 wheel alignment place in your area.

If you go to some tyre places they may call it four wheel alignment when they only align the fronts to the rears so ask what they will do to adjust the rears first. I had that happen once![

]

mr pg · Nov 2, 2011

Geometry that is out enough can cause the problem you've seen. I recall on one of my visits to Center Gravity that Chris told me of a customer whose 996 new tyres wore in a similar fashion. It's essential to have it set up correcrly, for both handling, and tyre wear. Take it to someoen who knows about Porsche geos.

Lancerlot · Nov 2, 2011

You don't say if the wear is uneven or over the whole tyre contact patch.
Try a complaint to your tyre supplier citing premature wear. There is a procedure manufacturers adopt for defective product.
Don't raise your hopes too much but it's certainly worth a try.
Otherwise book in to see Chris at Center Gravity - he'll identify and where possible correct any chassis misalignment or suspension maladies. Wear at the rate you've quoted is significant and unusual.
Regards,

Clive.

metropolis986 · Nov 2, 2011

Just to clarify; it was KwikFit doing the alignment and replacement of tyres not the OPC. I do want to go and tell them off but they'll probably say I was driving it on a track etc.!

It has now been booked for a proper OPC alignment.

I still find it shocking and feel that despite the alignment being wrong there is something else at play here (bent suspension?). 700 miles on new tyres and them burning halfway down (more in fact) is just not normal. I would have thought the OPC would see that yesterday (i.e. something else at play) when they serviced the car but apparently not. I did tell them just now over the phone that I would like this thoroughly inspected over (suspension etc.).

Still hacked off about the tyres though... If fingers crossed it was just the alignment, can I keep the tyres on with 3mm left for a while you think (the fronts are a lot better thankfully).

metropolis986 · Nov 2, 2011

To answer Clive's question the wear is actually not uneven (which is why my OPC was baffled when I told them the tyres are practically new).

I will go to KwikFit as well but I am not optimistic as you say.

I am just hoping there is no major suspension issue...

Christos

tscaptain · Nov 2, 2011

New tyres come with about 8mm (unless they are track tyres) and to wear 5mm in 700 miles is clearly more than just "unusual". As Clive asks, is the wear uniform across the tread or are they worn to 3mm on one side (usually the inside)? It's hard to imagine how it could be uniform wear across the whole width as misalignment significant enough to cause that sort of wear rate would surely show itself? And if the wear is significantly uneven I'm surprised the PC didn't comment on the fact.
If you are anywhere in the Midlands take it to CenterGravity (I'm not but I still go there[

])

Buddy · Nov 2, 2011

Ask Kwik Fit just what they did as the OPC is saying that the tracking is out and when they do the full alignment with camber etc on all four corners they can do a before and after printout, make sure and ask the OPC for the before printout as otherwise they will probably only give the after readings and it's doubtful if they will save the before readings.

If the wear is even I'd expect the rear tracking to be out by several degrees. Excess wear on the inner or outer edges would be camber settings, you may well find that all Kwik Fit did was front tracking aligned to the rears. Which you say were low.

Take a look at the tread face of the tyres and see if there are surface marks at an angle to the tread, with even wear that will demonstrate that the toe in/out is extreme.

metropolis986 · Nov 3, 2011

Update on this; tried it on with KwikFit and apparently they want me to pay for two new tyres and then send the rear ones (which are down to 3 and 4 mm each) to Michelin. They will do tests and if they decide they are faulty I will get my money back on the originals... Not something I am willing to go for.

I am seeing the OPC tomorrow for another inspection of the car and of course the alignment done properly. I've been looking at the tires more closely and the wear follows a very weird pattern. While the wear is fairly even the direction appears to be vertical rather than horizontal. The KwikFit guy commented on that and told me he's only seen that on very extreme cases of heat... Will report on what Porsche say tomorrow.

Buddy · Nov 3, 2011

I'm not sure what you mean by vertical and horizontal.

Tyres normally wear radially ( as from wheel spin and heavy braking both of which cause high temperatures ) or axially as in sliding sideways which again will raise the temp and is often caused by excessive toe in or toe out on the rears.

Did Kwik Fit tell you if they adjusted the toe in on the rears? Excessive camber can also cause high wear but is usually shown by different wear rates inner to outer edge of the tyre.

It really sounds as though the alignment is badly out, I had Michelins on my Cayman for around 20,000 mls. When you have the alignment done ask about the amount it is in error before correction camber, toe in, the lot.

Scotbox · Nov 15, 2011

I do sympathise-I had only 5,000 miles from my Michelin PS2 N3's on the rear of my 2.5 Boxster lately which really cheesed me off (but mine were 285x30x18 993 wheels im told) so have after much advice have bought Boxster Wheels but my alignment/geometry was out as well.
What is the difference between alignment and geometry ?
I am left with Michelin 225x40x18 front tyres which have around 5mm left but after my terrible wear I will not be buying Michelins again and may be purchasing Pirelli P Zero's N4's for the rears.

Mark_Bennett · Nov 15, 2011

ORIGINAL: Scotbox

I do sympathise-I had only 5,000 miles from my Michelin PS2 N3's on the rear of my 2.5 Boxster lately which really cheesed me off (but mine were 285x30x18 993 wheels im told) so have after much advice have bought Boxster Wheels but my alignment/geometry was out as well.
What is the difference between alignment and geometry ?
I am left with Michelin 225x40x18 front tyres which have around 5mm left but after my terrible wear I will not be buying Michelins again and may be purchasing Pirelli P Zero's N4's for the rears.

DO NOT MIX TYRE MAKES ! Seriously.

The Michelins will wear fine if the geometery is correct. If you mix tyres you are likely to find the handling goes out the window!

Edit:
In light of Buddy's post below, I have corrected "Alignment" for "Geometery"!

Buddy · Nov 15, 2011

Difference between alignment and geometry.

Alignment is simply the toe in/out usually of the fronts to the rear but should refer to all four.

Geometry refers to toe in/out of all four wheels plus castor of the fronts and camber of all four.

Camber may well be set differently according to the type of driving. track or road.