AppleFan1

I am getting very annoyed. For the past 3-4 service appointments (most minor), the technician at the dealer that serviced my S550 inflated the tires to 39 psi. Such air pressure is supposed to be limited to a maximum load. The normal load is 32. WHY are they doing this? Last Friday when I brought the car in for the 20,000 mile service, I specifically left orders with the service advisor to please inform the tech that I want the tires to be inflated to 32 psi.

So, when I picked up the car and started driving home, I set the display to the tire pressure monitor, and I was pissed. The tires were inflated to 38-39. I called the service advisor and complained. He said he forgot to tell me that the technician stated that "standard air pressure for the front is 38 and 39 for the rear." I said, the technician is dead wrong. Furthermore, the advisor told me that if I open the gas lid, it says what the cold/hot air pressure should be. By now, I was getting more angry. I explained to him that those readings on the lid are for load/weight the car is hauling and they are not a function of outside temperature. I also told him that if they are inflated to 32 when tires are cold, they will read about 34-35 after driving for a while and the tires get hot.

The advisor was brand new and I basically forgave him for not knowing what he was talking about. But I do not forgive the technician who worked on my car. Have any of you folks had this issue when they work on your car?

714Merc

Yeah, add me to the annoyed list for that too... I tell dealership now to specifically NOT touch my tires or wash my car. I even take off my amg tire stem caps before going in for service.
It's not just MB dealerships; when I brought my Escalade home in February I was bleeding air out of the tires for an entire week. They must of been set to 50-60lbs...

wilassasin

Sometimes having that extra pressure will help you avoid getting bubbles aka tire tumors when hitting potholes. However; if youre not in a location that is known to have an excess of potholes then you shouldnt have to inflate over the recommended air pressure value.

Im in NJ and my vehicle has 20" wheels , I keep my air pressure at 40psi.

Wolfman

First off, make sure you don't measure a warm tire. All listed tire pressures are cold tires and temperature easily accounts for 3-5psi.

Our dealer always inflates tires 4-5psi higher than listed to reduce premature tire wear (SL's are known for that). Haven't checked the S-Class

AppleFan1

Yes, Wolfman. Thanks. I always measure the air pressure when tires are cold. I am also very well aware of the effect the outside air temperature has on the tire pressure. And, as I stated on my post, the pressure increases by about 2-3 psi after driving the car for a few miles. Very high speeds also have an effect on the tire pressure since they get hotter with high speeds. But this time of year, with outside temperatures in the 80's and speeds of about 70 mph, the pressure increases by about 2-3 psi after driving for a while. I like the tire pressure to read 32 when the tires are cold so that I can have a more comfortable ride. I have driven the car for a bit over 20,000 miles now and the tires still look great. However, I had to replace the front passenger side tire because incredibly enough, I ran over a brick on the road at 70 mph and the tire was damaged. The rim also had a bit of a dent and it was repaired last Friday. I don't think there is any vibration now after the repair.

I am a meteorologist, and I should have knowledge of the physics involved here. Hey, they should have consulted with me on the stupid "Deflategate" fiasco.

hyperion667

sounds annoying: having to repeat yourself to the one/s that are supposed to care for your car.........I keep mine around 37 or 38 cold, then again I have 265's all around

Mitch Alsup

My Ferrari likes its tires ate 35 PSI if I am doing street driving, confirmed with a probe tipped pyrometer to verify the pressures and suspension calibrations are spot on.

The F355 happens to have the same tire footprints as my S600, yet weights only 3250 pounds, compared to the nearly 5000 pounds for the S600.

I have not had time to put the pyrometer on the S600 wheels, but back-of-the-envelope math indicates 39 PSI is in the right ball park.

WSH

Service at even best dealers even if repeat cust w/best SA, etc is suspect and requires much of own instructions/verification...been that way forever w/any car on planet....no one smart/risk-oriented works in auto industry, let alone at dealers (kinda like at inv banks despite far higher compensation and far bigger amts of money at risk (though not personal safety/health risks of cars/driving))

Irony of modern Net is any intelligent driver of >$100K cars prob knows issues and tail risks of any cars far better than any tech/SA or race car driver or MB CEO/R&D chief....wouldn't let the "expert" fallacies/gibberish fool you vs (un)common sense of own

Knowing these issues/tail risks/oppty costs is part of why I have never kept any new MB for more than 2yrs, minimizing my exposure to dealer to one annual visit for oil change/replacement of rear tires (where ~20% of time they manage to scuff a rim during process).....and shortly thereafter get rid of the ole car for a new copy....and move on....these are quite disposable/obsoleting devices, just like iPhones, but with far more profound safety risks as they decay and/or w/any post-factory "work" (think airbags/sensors, etc etc)...