MILIN1609

I have a 2001 S430 with 18" Lowenhart wheels and 245/45ZR18 96Y tires. My question is: since they are not original MB tires, should the tire pressure be same as listed on door. 29psi in the front and 32 psi in the rear. or different? I just bought this vehicle last month. So, I am still learning. Any sugestions, please.

x-tian-230k

Look on the tires. It should have a PSI rating.

BBH

That tire rating is the maximum recommended. Most authorities recommend following the manufacturer's recommendation. This is typically based on ride comfort, so if your priorities lie elsewhere...

MILIN1609

When I bought this car, I drove about 1200 miles to bring it to my house. I didn't check the tire pressure at that time, but the ride was excellent. After reaching home, I checked the tire pressure. It was a bit low in all tires. I adjusted to the MB specs. But since than, I am not happy about the ride. That's where this question arised, should I follow the MB specs OR not? Will it hurt the tires, if I put little less air?

newton22

Find out what the maximum pressure rating for your current tires are, and then tell me how the car is driven usually, and I'll get back to you with an answer.

MILIN1609

Thanks for your offer to help.
The details are as listed.:
BFGOODRICH g-Force T/A KDW tires
size: 245/45ZR18 96 Y
Max load 710 kg(1565 lbs)
Max Pressure 350 KPa (51 psi)

The car is driven usually on city roads and on interstate, roughly 50 miles a day with an average speed of 50 mph.

sprink49

Go with the sticker in the door jamb.

newton22

My opinion-

Comfort: about 29-32 PSI cold all around
Mixture of comfort and economy: about 32-35 PSI
Economy: 37-42 PSI
Sport (for cornering) - about 40-45 rears, 35-40 fronts
Sport (for straightline runs/drag strip) - About 40-45 fronts, 20-25 rears

From your description of its daily use, I would probably go 33 all around or somewhere close.

You guys can chime in if you believe my pressures aren't exactly right.

sprink49

Sounds good to me...I run 32 all 4.

MILIN1609

Thanks a lot for the info.

koreanpers

i just had my 18's put on and asked that exact q to the installer, he said it should be fine to go 35-40 all around. the michellin tires say max psi of 51 i think.

desipyar510

Guys, sorry if this is off-topic, but it has been mentioned in this post. Could anyone shed light as to why you would want different pressure in the front tires and back tires (ie. 29 psi in front and 32 psi in back).

I am still new to all of this and am trying to understand why this is the OEM recommended pressure.

Thanks a lot!

newton22

That the pressure recommended for the stock tires and for comfort. Pressures vary depending on the type of tire you have and how you use your car.