This appears to be a stupid question, but I'm at a loss so here goes -

Wife has BMW (nothing I could do about that) that appears to eat through rear stock tires (EcoPlus Continentals). Wife also insists on stock tire replacements (nothing I could do about that either - she wants everything exactly BMW or what came as stock on BMW). My advice and common sense means nothing when it comes to this damn car. So anyway, my question:

I'm already on the second set of rear tires, first set went much faster before I realized there was a problem, but the second set is already showing signs of overinflation (wear pattern in the middle greater than the outer edges). I have religiously kept the air pressure at the recommended psi (35), but still an overinflation pattern, so I started thinking, does ambient temperature (cold tire) mean a reading on an undriven tire:

1) first thing in the morning
2) at the highest outside temperature of the day in the shade
3 at the highest outside temperature of the day in the sunlight.

This might make a big difference in Florida, as a morning reading could be 32, a noon reading in the shade might be 33, and a reading while the car sits in the sun could be 35.

Anyway, since I'm stuck with stock it's figure out what I'm doing wrong or buy a new set of tires every 6 months.....Funny that I got 70k out of my stock Wranglers on my F150 but can't even get 15k out of stock BMW tires.

 

The cold psi typically to me has been cold weather. I don't check the tractor and truck tires until there is a significant sustained temp drop. I'd try dropping the psi to 31 or 32 psi. Heck I'm only running 35 on my truck for towing.

 

Hey I think your wife tried to race me at a light yesterday......thats where your tire wear is from!!!!!

Just kidding.......35 pounds sounds like a lot for car tires.....I'd try 30.....and really you should not go with stock tires EVER....all car companies put the cheapest rubber they can on them. There's no warranty on factory tires........ever wonder why? Get a decent set of dunlops or BFG's and the car will drive way better and get better longevity on the rubber. Just my 2 cents.
Take care Phil

 

What does the BMW owner's manual or door sticker recommend for tire pressure? Center wear is over-inflation. 35psi is higher than most passenger car tires are recommended to be inflated. I usually run 1-2psi less in the rear tires.

 

Are you sure the reccomended psi is 35 thats what it is on my truck id put it at 30/31 i mean who cares about the cold temp whatever if its overinflation wearing what do you do= deflate it a lil bit problem solved

 

tires also get hot when being driven. so alot of hard driving will build the pressure. what is her driving style?

 

OK, Casper is on his soap box here, please bear with me. . .

We all need to keep in mind that the PSI listed on the doorjamb is for the baseline model tire installed on a vehicle. If it is a "P" series, you can expect, for most vehicles, that the number will be between 30 and 35 PSI, which is a very common max cold PSI rating for a "P" series tire. With that in mind . . . from a safety and tire wear standpoint, always reference the ratings on the tire sidewall, not on the doorjamb. Your vehicle may have been upgraded with different tires at the dealership, or a sports/off-road package installed, etc., which negates the baseline standard on the door. Case in point: My truck came with the weenie P235/70/R16 Firecraps. They were rated at 35 PSI max cold. I replaced them with Revo's, size P265/75/R16. They are rated at 44 PSI max cold. If I were to run them at the doorjam recommended 35 PSI, they would sag like no one's business. I guess my point is that the PSI on the door is the car manufacturer's recommendation, not the tire manufacturer. Tires are designed to run at their max cold PSI without abnormal wear, and running at or near max PSI will always give you better gas mileage, though this may mean your vehicle rides a bit more "stiff".
Finally, checking your tire pressure with a quality gauge in the morning before you run the vehicle will give you the most consistent numbers.

Sorry for the rant . . .