PetrosSRB

Good day,

What would be the optimal tire pressure for W212 Saloon?

Front tires 235/35/19
Back tires 255/35/19

Thank you very much for your help!

DFWdude

What is the max pressure molded on the tire sidewall? Subtract 10% and go for it.

Mercedes-Benz has no earthly idea what tires you will install on your "saloon."

PetrosSRB

My mistake about the ''saloon''. Yeah.

So you're saying 45 wouldn't be too much?

DFWdude

Low Profile tires have different inflation suggestions than regular sidewall tires... width also dictates pressure.

Point is... The tire manufacturer makes several tire sizes, each with their own pressure recommendations, based on their testing of their tires.

If you go by the pressure amount on the gas filler cap (32ish psi), then you will burn through the tread life on a 50psi tire in no time flat.

Assuming your tires are rated at 50psi Max pressure, subtracting 10% (5psi) would be the minimum "minus" pressure... 45, 44, 43, 42psi would be fine, tuned further based on how you like the ride.

My tires are set at 44psi (cold) and they are 18"

jadatis

Made you a cold pressure/ axleloadcapacity list for both tires, with build in maximum reserve, at wich comfort and gripp is still acceptable.
For that I give 90% of calculated axleloadcapacity for 160kmph/99mph, wich then is maximum speed to use.



First googled the given sizes, these low aspect ratio tires are almost always XL/reinforced / extraload, and only found XL googling.

Front 235/35ZR19 91Y maxload 1356 lbs AT 42 psi upto 99mph.
Rear 255/35 R 19 96 Y maxload 1565 lbs AT 42 psi upto 99mph.

In front of cold psi for front axle, behind for behind. Logical way I think.

Now you " ONLY" have to determine the axleloads in your use 99% acurate. Succes with that, the most tricky part and your responcibility.
Frontaxleload/ cold psi/ rear axleload
1149 lbs/ 18 psi / 1326 lbs
1204 lbs/ 19 psi / 1389 lbs
1259 lbs/ 20 psi / 1453 lbs
1313 lbs/ 21 psi / 1516 lbs
1368 lbs/ 22 psi / 1579 lbs/ minnimum EUR
​​​​​1423 lbs/ 23 psi / 1642 lbs
1477 lbs/ 24 psi / 1705 lbs
1531 lbs/ 25 psi / 1767 lbs
1585 lbs/ 26 psi / 1830 lbs/minimum US
1639 lbs/ 27 psi / 1892 lbs
1693 lbs/ 28 psi / 1955 lbs
1747 lbs/ 29 psi / 2017 lbs
1801 lbs/ 30 psi / 2079 lbs
1855 lbs/ 31 psi / 2141 lbs
1908 lbs/ 32 psi / 2203 lbs
1962 lbs/ 33 psi / 2264 lbs
2015 lbs/ 34 psi / 2326 lbs
2069 lbs/ 35 psi / 2388 lbs
2122 lbs/ 36 psi / 2449 lbs
2175 lbs/ 37 psi / 2511 lbs
2228 lbs/ 38 psi / 2572 lbs
2281 lbs/ 39 psi / 2633 lbs
2334 lbs/ 40 psi / 2694 lbs
2387 lbs/ 41 psi / 2755 lbs
2440 lbs/ 42 psi / 2817 lbs/ reference-pressure
2493 lbs/ 43 psi / 2877 lbs
2546 lbs/ 44 psi / 2938 lbs
2599 lbs/ 45 psi / 2999 lbs
2651 lbs/ 46 psi / 3060 lbs
2704 lbs/ 47 psi / 3121 lbs
2756 lbs/ 48 psi / 3181 lbs
2809 lbs/ 49 psi / 3242 lbs
2861 lbs/ 50 psi / 3302 lbs
2914 lbs/ 51 psi / 3363 lbs/ mostly maxcold pressure

DFWdude

Sorry, too much rocket science to figure pressure for me.

PetrosSRB

Sorry for the late response.

Really appreciate both of the responses and details put into them.

Front and back tires are all 50 Max PSI.

I'll try running them around 40 PSI and go from there.

Everything you're saying makes sense so I'll see how the car behaves after.

I've read a lot of reviews where it basically changed how the car's behaving after getting higher tire pressure.

ColonelKlink

Yes, changing tire pressure will change handling. A 'soft' low pressure tire will have a lag in response. A 'hard' high pressure tire will have a more quick response. But, there are other consequences as well. Too high tire pressure transmits pothole shocks that can damage the rim (and other components). Too low tire pressure does not protect the rim either. (there are plenty of threads here about cracked rims. I have repaired two.) Around the City, I have close to 'normal' pressure due to bad roads. For my long distance 'Autoput' driving, I run higher than normal pressure. Load factor (as mentioned above) and temperatures will also have an effect. Your tires are your only contact with the planet surface. I support your attention to them.

Bruce Hubbard

Pirelli 19 inch 275/30 on the rear 9 inch rims and 245/35 on the front 8.5 inch rims
Around town I run 42psi
On the highway for less rolling resistance and better fuel economy I run 45psi

The wheels look nice when you get rid of the rusty rotor hubs by painting them silver
and the stone guards silver as well, and paint the brake calipers red.

A 7.5 inch alloy rim will fit in the wheel well if you want to ditch the junk space saver spare wheel
Just pay attention to the size of the tyre you fit so that it is close to the same circumference as the others on the car

juanmor40

Personally I do not like harsh rides. Setting at 40+psi is too harsh for me.

Run mine at 35/36 psi cold. When hot they reach 39/40, perhaps 41 in the middle of the summer, and running hard on the highway.

Vehicle @98K miles on the 2nd set of ContiContact. First set lasted 50K+ miles. Currently rear ones have 8K left at best, front ones easy another 15/20K.

NOTE: never rotated either set, and the car was checked (no alignment required) for alignment at the 50K miles service. My car is still speed limited, so the maximum speed on either set has been around 120mph