joliett

The tires are wear rated for 50,000 miles. The tires lasted 40,000 miles with the extreme wear on the inside edges (so actually the wear probably was evident at 30K miles). The passenger side wore worse, but both tires are wearing on the inside edge. The rest of the tire tread has a bit more tread over the wear indicator.

I'm the first one not to trust unknown mechanics - I'm an engineer - but this place is run by the Porsche Club technical advisor for the East coast. I've known him and his wife for 30 years, through 3 Porsches and now my C6.

I may have been running 28 lbs cold, which would quickly go up to 30 psi while driving and hence it would fool me...maybe that was my problem. And the worse wearing passenger tire lost air for part of it's life, so it may show low pressure but then the DEC would quickly go back up to near 30. That's the problem...I'm almost certain.

Inflating and checking air pressure MUST be done when the tire is COLD...and rechecking especially when the air temperature changes .

buckmeister2

[QUOTE=MH663;1594998834]Your guy is full of BS. The only wear you will get from tire pressure is when "Both" the inside/outside wear simultaneously, underinflated or "Center" tread wear, overinflated. If only the inside edge or outside edge are wearing uneven then its an alignment issue.

Wellll, the OP did say "my excessive outside and inside tire wear". Then, he went off on a tangent about inside tire wear. A bad alignment will not give you both excessive outside and inside tire wear. Hard to say what is really happening.

cmonkey713

[QUOTE=buckmeister2;1595008451]
Right on point, classic example of under inflation.

joliett

[QUOTE=buckmeister2;1595008451]This is absolutely correct..should have been obvious to me..."The only wear you will get from tire pressure is when both the inside/outside wear simultaneously..."

HOXXOH

Your alignment shop says your alignment was perfect and I'm assuming you probably had that done 40K miles ago when you bought tires. I'm guessing that you had normal wear on the tires you removed at that time.
Part of your first post said you had one tire worn on the inside to the cords and now you say both fronts are worn on the inside, but one is worse. That's typical of a bad bearing/hub or a suspension problem. I'm at 145K on my '08 and have no bushing or tie rod problem, so I'd suspect you don't either.
I suggested yesterday to check for a bad bearing/hub, but haven't heard if you did yet. It makes no sense to talk about past air pressure issues if you haven't first eliminated a possible mechanical problem.

BTW, what is the temperature that you consider to be COLD? Your cold in NY is a lot colder than my cold in AZ.

joliett

I will check the bearing Sunday.

BTW, I did scrape a low wooden curb - right at the apex of circular U turn in a closed dark parking lot. It made a small scrape mark on the wheel, but afterwards I did not notice any misalignment, pulling, or noise. But now that I think about all this...I bet that's the problem. Thanks HOXXOH.

Trick question?? COLD is ambient temperature...

AORoads

Yes, COLD is ambient and as said by several above, it can be 30 or 105, which means you have to adjust accordingly. And cold also means not driven on for at least a few hours. HOX is also correct that when you put your car outside, if one side is in the sun it can very easily have tire pressures above the other side in the shade. Just repeating what you already know.

mikeCsix

I'm as bad if not worse than HOXXOH for tire pressures, and I'm going to be a little contrary here. It could very well be your alignment too, the front toe may be off. These cars like some negative camber front and rear but it isn't camber settings that wear tires, its toe. Since it sounds like you don't visit race tracks and want the most mileage out of your tires I would set the camber settings to the low side of OEM and set the toe settings to 0 or very slightly toe in for the front and 0 toe for the rear.

AS for pressure, 30 cold. Even when I am on the race track I'll keep them close to 30 - but that is a hot setting and I regularly see more than 1g in the turns on street tires.

Red08

I keep mine at the recommended 30 psi when checked cold.

Mad*Max

What kind of tire is rated 50k miles on these cars?

joliett

245/40ZR-18 Michelin Pilot Sport A/S 3+ ZP (W- or Y-Speed Rat Run Flat, 5-Rib Tread Design

285/35ZR-19 Michelin Pilot Sport A/S 3+ ZP (W- or Y-Speed Rat Run Flat, 5-Rib Tread Design SL

Mad*Max

How well do the all-seasons grip? I was thinking of going that route soon...

joliett

They're quiet and they grip like I'm glued down to the road.

WW7

If you use these specs you won't have any uneven wear caused by alignment... These are the specs shops should use for street driven cars not used for racing.....WW

mikeCsix

My guess is not as good as a good HP summer tire because the tread isn't set up for best handling, but more for varied seasonal changes.

During one of my hpde's, I was getting ready to pass a Porsche 911 as we came out of a turn. His tires couldn't hold his line so he spun in front of me. I was able to safely get around him and caught up to him in the paddock. I looked at his tires and he had a new set of Michelin A/S tires on. I'm not suggesting these are bad tires, just be aware they may not corner as good as a run flat.

Gary '09 C6

^ all-season tires may not corner as well as a summer performance tire (assuming proper ambient temps. for both)

run-flat vs non run-flat is yet a different parameter (same tire type)...