Diabolis

Those are all for cars with 18" wheels. The required tire pressures on cars with 19" wheels are even higher. This is the sticker from a 2013 coupe with OEM multi-spoke 19s:

Critter

One must also realize that most likely you do not drive around with three people and three bags of luggage in the trunk unless you are looking for traction aids, .
Diabolis the strange reading on your gas door shows 44 in front and 42 in rear with specified loading, but full load seems normal. I guess the 19 inch lower profile needs less air pressure. Or two in the front and 1 in back with three 24's in the trunk.

Diabolis

Er - I suspect you mean the 19s need more pressure (they do in order to maintain the load rating as the sidewall is smaller), not less. I run 45F/45R on PSS 19s. Even tire wear throughout.

Ingenieur

Went from bar to kPa lol
2.7 bar 39.7 psi
2.8 41.2
3.1 45.6

Critter

Realized that you have a coupe, that is why the rear pressure is less on the gas door. Less overhang on the rear axle as compared to a sedan. 44 front 42 rear
The car must hit hard when driving over so so pavement, reduced pressure would give you better ride and still uniform wear. 38 front/rear give it a try. IMO

Diabolis

On our downtown Toronto roads, 38 psi in a 19" tire is guaranteed to result in cut tire cords and/or bent rims within half an hour. Yes, the ride is jarring, especially on the APX cars with the 10 mm lower & stiffer suspension, but that's par for the course.

whoover

It would be nice to know why the 18" sedan pressures were changed from 39/39 to 41/41 and from 41/45 to 44/46. As far as I know the suspension is the same. Different OEM tires? Or would the new specs be recommended for the older cars now?

Maybe a tech can shed light.

zibby43

Not sure what you're referring to with the sedans but if you're referring to LCI sedan vs. non-LCI sedan, then yes, the suspension setups are different.

The standard LCI sedans now come with ContiSportContact 5P tires (at least that's one option).

whoover

LCI = facelift?

What kind of suspension changes were included? I have the Contis and like them. So the higher pressure could be for them?

Ingenieur

use whatever is on your gas flap

zibby43

Yep LCI (life cycle impulse/improvement) is the same as facelift.

The changes included: a redesigned front axle; a reinforced rear axle and widening of the front track; stiffer elastokinematics and revised geometry with more negative camber; and a larger rear stabilizer bar

They also revised the spring and damper rates.

zcct04

Does this mean that the appropriate spacer for the front wheels is different for the pre and post-facelift cars?

Don't want to hijack this discussion - we'll pick up the spacer question in a new thread:
https://mbworld.org/forums/c63-amg-w...ml#post6055137