2009c63soon

Morning all. OK, so I have the 19" twin spoke staggered factory wheels.

I picked up the car last weekend and checked the tire pressure - amazed to find them 45psi front and 47psi rear! Felt a little high speed roughness that I attributed to this.

The inside door sticker, which is correct for the 19" option shows 32psi. I set my cold tire pressue to 32 last night and reset the system. This morning I get a tire check warning - pressures are still around 32 (+/-1) but the car does feel very floaty on the highway. After talking with teleaid tech support, they reinforced the 32 but advised I check inside the fuel door for another sticker. This shows 32psi <100mph and 35psi >100mph.

It would seem that 35psi is the way to go but am interested if anyone else has worked through this same issue and found the optimal pressue for performance, wear, handling and safety.

Thanks!

steveb9771

I have staggered 19's on a 2007 with Continental Contisportcontact 2 tires. I have been using 35psi cold and add air when it gets down to 32psi.

Rear tires wore out at about 17,000 miles. Uniform wear across entire width of the tire. Replacement rear tires were slightly over $400 each mounted. Most places charge over $500 each.

2009c63soon

Thanks Steve - most helpful.

17,000 sounds great. C63 drivers are getting ~5,000 per set with regular driving (without burnouts).

WSH

Have always gone w/the >100MPH rec'd tire Ps; IIRC, there's some process to reset TPMS calibration after changing tire Ps; what brand/model of tire does your car have? Was car sitting for mths before you bought it (flat spots/tire decay esp w/a 5K lb car)? New car (risk of bent wheels/misalignment in a used car)? ABC in Sport mode?

Have only gotten perhaps 6K mis out of rear tires on previous CL600/63 030; I never do aggressive launches from 0 MPH but almost always aggressively accelerate in mid/upper-range (600 or 65 truly supersedes 63 in this range) and stress tires (and brakes) w/exuberant mtn twisties driving (yes, I rather prefer a 5000lb luxury car for my mtn twisties pleasure driving)

Red Marko

I just switched from my winter tires (Soto Zero) to my summer ones (Michelin Pilot Sport PS2), I set them to 33psi, tires being checked every 2 weeks.
I've got 19" double spoke wheels (MB), which by the way I bent and replaced 4 times already within 1 year.
Thank God, I purchased tire/wheel replacement warranty ($950), one of the better deals I made at the time I bought the car.
I'm covered for 5 years with replacements if MB can't balance the tires. My SA is telling me that, the Company is losing their shirt on the East Coast, West Coast having MUCH better roads.
But I digress.
Michelin - 33psi works perfect for me.
Contis (OEM) - 35psi was good.
BTW, no comparison between original Contis (flobby) and Michelins (fantastic traction and cornering). Again, you get what you paid for.
Mark.

2009c63soon

Thanks guys - running the oem conti's. Good point re: the car sitting around before i got it - I had wondered about flat spots. Might bite the bullet and just put some new rubber on all around. Michelins seem like a good option

neodoc

Something similar happened to me a couple of weeks ago when I took delivery of my new GL550. I checked the tire pressures and was shocked to find them at similar pressures to the ones 2009c63soon had on his car. My truck was built in 3/09 and I took delivery one month later, so sitting around wasn't much of an issue, but my guess is that the factory and/or the dealers set tire pressures up high to avoid flat spots while the vehicles sit in their lots. In my case, my truck was delivered to me from about 200 miles away and I guess the dealer forgot to set the proper tire pressures before the driver left their lot. I'm very meticulous about tire pressures so the first thing I did the morning after receiving the truck was check the pressures. I let some air out to reach the recommended 33 psi and reset the TPM. No problems at all to report.