youngshep

After discovering a nail in my tire and plugging the hole while the dealer gets a new tire in, I checked the door sill to double check the correct tire pressure - 45psi for the front and 48psi for the rear. I hadn’t bothered to check before, assuming the dealer had them inflated correctly. They had been at 31psi.

I recall on my GTC that it called for 42 but many ran softer to compensate for the rather firm ride.

Anyone have thoughts on the sweet spot for this car?

California John

The sweet spot is 31/32. That is what is given on the fuel filler door and is much better than the driver's side door sill. Much more compliant ride.

FlyingBear

Ditto. Mine came with the highest pressure settings - maybe it’s a liability thing for dealers to deliver cars that way - but that’s for a fully loaded car operating at speeds that would get you jail time in all US states and likely the death penalty in VA :-). The fuel filler door table is my guide.

khiroshima

Did a quick search and this seems to be the only relevant thread . . . My car was delivered with 41s on all corners and I got a tire fault code, rechecked and the fronts had increased to 42s (about an hour drive) and the rears remained at 41s. Upon checking the gas cap, it looks like 155 mph (way faster than I will drive) recommendation is 31/31, I will never have 4 passengers and full-luggage; my question is if the group has also arrived at this conclusion 31s in all corners. Thanks! KH

California John

31 PSI cold is your friend.

CharlestheCat

I’m a fuel door man too! My last car was an E63s and the numbers on the fuel door made the car drive way better than the driver’s door numbers.

And if you go to the track you’ll want to drop them a bit lower than that yet!

khiroshima

Thank you, that was my knee-jerk as well. I text my MB guy and he said that they stick to 41s and that I can go with 31s, but my tires would wear faster . . . Not sure that makes any sense, HaHa

California John

He's probably right that the tires at 31 PSI will wear a little faster. The ride is more compliant at 31 PSI and you might imagine that there is a little more tread on the road. At the higher pressure the car will probably get slightly better gas, mileage and that is one of the reasons why the higher pressure is recommended by some.

wem

I brought my SL back to the dealer today to address the critical battery messages from the trickle charger. While I was waiting for my loaner, the service department checked the tread depth on my tires. The rear two are fine, but the front tires need to be replaced. The car has about 6100 miles. I guess that goes to show that I enjoy driving the SL enthusiastically and the periodic visits back to the dealership are small nuisances. Fyi, the price for the tires at the dealership were pretty close to the price at Tirerack.com. I told the dealer to hold off on the tires for now. I want to have some more seat time to do more spirited driving (I haven't done launch control yet).

RTC63

Perfect tire pressure if you drive alone and/or with a passenger and no luggage at all.
Good for speeds up to 250 kph and very good for spirited driving through curves.

MB2timer

If the front tires are not matched in pressure to within about 2 psi, the steering begins to pull to one side.
Almost every time this happened to me, I started down a thought trail of alignment.
What I have learned is, that don’t immediately think alignment, until you check tire pressure.