stugilmour

Well, it is that time of year approaching again.

My tire data plate only has recommended pressure for my stock 265/45R20 all weathers. (34 psi front / 41 psi rear).

Dos anyone have the plate pressure data for the 19" rims and 255/50R19 tires?

Thanks

Stu

efzauner

its 34 front, 39 rear. 2011 R350

stugilmour

Thanks for that. Interesting as I thought the pressures would be a bit higher rather than reduced.

Stu

auto385

The 39 lbs on the rear is a little high. Remember, the suggested tire pressure rating is for a fully loaded car. In reality , you have a lot less weight in it. I run mine at 34 all around and the vehicle rides nice and smooth. If you want to be really **** about it, you can calculate proper rear pressure by measuring the belly of the front tire and matching the rear to it. This means measuring the maximum width of the tire some where up the side wall above the contact point above the pavement. Take several measurements as you roll the tire forward. I've done this before and it is surprising what you will find out. This is a redneck way of measuring corner weight if you don't have a set of NASCAR scales. Good luck.

efzauner

that is taken directly from the sticker... same that is on every R. Also remember that the pressure will vary 1 psi for every 10 degrees F. So If you check and fill the tires on a wam 60 degree fall day you will lose 6 psi by mid winter 0F. so much for TPMS.

auto385

Once more, the sticker is for maximum load only. Go check the sticker for an Audi S5 or S6. It will have different rear tire pressures for how many passengers are in the back. That 's where Ford got into trouble with. They recommended 27 psi on the sticker for the back tires of the Explorers. But that was for no load. The owner's manual actually said something else, but who reads the manual.

If you look at the R-Class and see where most of the weight is located, it would be in the front, not the rear. That's why I said to keep them at least the same pressure if traveling without load.

Yu Chem

Is it Bluetec? Diesel R has a bit more weight on the front, not sure whether it influences the tire pressure.
This is what I have on my 2012 R350 Bluetec with 19" tires


Tire pressure on 2012 Mercedes R350 Bluetec. Tires are 255/50 R 19

stugilmour

Sorry for the lousy picture. Pressures the same as above.
Thanks Yu Chem. That is exactly what I was hoping for.

Yes, my car is a R350 Bluetec Canadian Model with conventional non- run flat tires. Interestingly my tag only gives fully loaded tire pressure rather than two pressures like your tag.

So the conclusion I would take away is no change in recommended full load tire pressure when chNging from 20” to 19”.

Thanks guys

Stu

auto385

41 psi in the back is way too much