OCcarguy

I have a 2012 CLS 63 with 11,500 miles and the front tires are shot because of excessive wear on the outsides. The tread on the centers is good. One of the rears is also wearing on the inside. This is my 3rd CLS AMG, 1 CLS55 and 2 CLS63s and I averaged about 20,000 miles on a set of tires, various brands, on the previous 2 cars.
The dealer can’t offer any explanation. The wheels have been aligned and balanced on a Hunter road force machine. Here is my question. The tire pressure chart on the inside of the gas filler flap recommends 39 lbs all around for driving with 4 passengers and luggage at speeds up to 155 mph, and 51 lbs all around with 4 passengers and luggage up to 186 mph, BUT the sticker on the pillar by the driver’s door says 51 lbs all around, period. Which is correct?
I have been keeping the pressure at 41 lbs faithfully since I got the car. The dealer says 51 lbs is ridiculous but now I am wondering.......
I need to replace the Conti Sport Contact 5Ps pretty soon and would like to figure out the tire pressure question before I get new tires. I live in SoCal where it is dry most of the time and am thinking of getting either Bridgestone Potenza S-04 Pole Positions or Michelin Super Sports but would appreciate any other suggestions.

bacchus813

I found 39lbs is too high. I have it at 35lbs so the car is more stable. 41lbs is too bouncy and 51lbs is just ridiculous.
As for tires I would op for Super Sports because it grips!! It wears fast though, generally about 15,000 miles.

Vic55

I think we have seen 3 or 4 posts about the C218 and TP's... on stock 19's I think you should run 36-38 cold psi... I did this and got good results.

The 51 psi number is for actually going over 150+ mph with all the weight in the car- which will never happen I hope.

As for your wear, if your outsides and insides are worn but not centers that is the result of lower air pressure. The rears are going to wear on the inside due to factory camber and so much tq pushing the car from digs and from rolls.

Run 37 psi cold.

OCcarguy

Thank you both for your replies. Vic, I agree that wear on the outsides would usually indicate low air pressure but I have been fanatical about keeping the pressure at 41 lbs since the car was new. So if 41lbs is too low, then your suggestion of 37 lbs wouln't work. I will continue to experiment with these tires until I replace them but I am still at a loss here.

Thanks, Chuck

Vic55

I have not seen any adverse wear with my pressures (when I had the stockers)- very odd that you are. Of course I swapped my stockers out and run 38 cold on 20's now.

wheelsloose

Are you still running 37 psi with your HRE's. I am about to add 20s and wonder if you think 37 is still a good number

hyperion667

hmmmm, I've been maintaining around 48-49 on each tire...
feels pretty good, planning on getting a rotation and wonder if I'll see any odd wearing

wheelsloose

Rotation? Don't you have a staggered setup that can't be rotated?

hyperion667

they are staggered, but I can switch sides with them at least.......

Vic55

I run 38 cold on all the way around on the HRE's per HRE.

Wow thats way too high---- you have to be feeling the pavement underneath you and turn in's at higher speeds will not be optimal.

hyperion667

hmmmm....it feels okay to me, if it's bad for wear I'd lower them....
guess I'm just used to it...I'll see how they feel with lower pressure..
but those numbers above are warm tire numbers, so I guess they're a few less cold...

I have also been averaging 20-22 mpg, think the higher pressure relates?
gotta love this forum....

otakki

Having a solid metal disk in place of wheels/tires will definitely eliminate any drag from that area and enhance mpg.

ajag

Drop the pressure to 38 and hammer it, you'll notice a lot more traction.

Vic55

Tire pressure might make up for 1 mpg one way or the other but its a small factor. You are getting that mpg because you are NOT on your car enough... I never clear more than 15 mph in my car and I drive on the freeway alot too.