Tires: Tire Pressure, 2000 mercedes s430, tire placard

Question
I have Nexen 255/35 R20 on my 2000 Mercedes s430.  What is correct tire pressure for this car on these type wheels?

Answer
Will

According to Tire Guides, a 2000 Mercedes S430 originally came with 225/60R16 98H inflated to 29 psi front / 32 psi rear.  Please compare this to your vehicle placard as the rest of what I write is based on this.

On every vehicle sold in the US, there is a sticker – commonly called the tire placard - that lists the original tire size and the proper pressure for that size.  The placard is usually located on a doorpost or in the glove box – but sometimes it is located in the trunk or on the fuel filler door.

So if the info I posted is correct, a 255/35R20 needs to have 34 psi front / 37 psi rear to get the same load carrying capacity.

But you might want to consider that the sidewall are pretty short and that increases the risk of impact damage to both the rim and the tire.  I'd recommend you use 3 to 5 psi more reduce the risk.