What pressure bar/psi, should i load the 20 inch wheels?

I have 3,2bar at the rear land 2,6 at the front but i think is not right

 

I suggest you direct your question to the Tire Rack, one of the forum sponsors.

 

It should state the preferred pressure on the sidewall of the tire

 

I've been running 34psi in the fronts and 40psi in the rears but I wonder if I should run something different..

 

I have been told to run factory recommended tire pressure of 36/44 Should you hit a rut or bump in the road less likely to bend a rim.

 

We suggest you increase the air pressure 2lbs per every inch you increase the wheel size.

So for example if the door says 30 for the fronts and 40 for the rears for 19's, and then you put 20's on the car, run 32 and 42.

 

Most tires tell you what the max psi the tire's can hold but this is not what you should be running.

 

what pressure should i run with 325/25/20?

 

whats the door say for the rears? I think its 42 or 44lbs. Whatever the door says, add 2lbs to it and you should be just fine.

 

The stocks are 19'' 305

 

Is there a reason for this?
I would have thought since larger rim makes the car's ride harsher, if anything you want to decrease the tire pressure?

 

It depends on the car really. Over the years from selling wheels and tires and talking to manufacturers. However on the cayenne when you go from 18's to 22's thats an 8lb increase which brings it up to almost 50 which is near the max load for the tire so in that case we bring it down some. But most SUV's now are coming with 20's so we shouldn't run into that issue so much.

 

To Original Poster,

Is 3.2 bar = 46 psi for rear, and 2.6 = 38 psi at the front? I think unless you are measuring this in the Sahara , you are WAY WAY WAY too high.

Porsche's recommended is 33/39 (cold ---> car not driven). However since air pressure varies with temp, these numbers go up and down depending the ambient temp. When it's colder like it is now, the reading could be quite a bit less.

As a starting point, I would use the TPMS in your car. Set the car to "Partial Load," and use the differential reading, the one that you use the stalk to check, so that it reads **zero** in all 4 tires. The TPMS takes care of temp variation so even if it reads say 31/36 early in the morning when it's 50 degree F, you are ok AS LONG AS the differential reading is zero.

My opinion is that the stock Turbo's suspension is so soft that a lot of dealers compensate by over-inflating. How do I know I am right? I don't. Just kidding. My car has Bilstein and 19 wheel, and with this method I find the car to be perfect about 15 minutes into a drive, when the tires are properly warm. I also use a reference level gauge but that's another issue.

I would start with this and see what happens. If you need to inflate a LOT more than this, I would suggest you click the thread in my signature and get Bilstein.

 

3,6 at the rear and 2,6 at the front seems to be perfect, thx Cannga,

thank you all for your interest

 

Please do not listen to this...that is the maximum PSI for that tire, it has nothing to do with the vehicle it is one...on a passenger car you should not be anywhere near the maximum PSI on the tire. If you upsized your wheels the generic rule of thumbs is about 2 psi per 1" you went up over the PSI on your door jam. The best way to do it however is to look up the load carrying capacity of your factory tire at the factory psi and then find the PSI for the new tire where load carrying is equal.