Yoshimura

Sticker on pilar shows different tire pressure for different tire dimension. However, my 255/50R19 are not listed. I put 32 but noticed that thread width is not fully utilised on the rear ( almost fully in the front). Could it be an indication that my tires are little bit overinflated?

zepharus

at 32?? I would think they may be UNDERINFLATED

Yoshimura

What pressure are you running? Audi recommendations for FULL LOAD are as follow:

235/60R18 32/32
235/55R19 33/33
255/45R20 33/33

Techm8n

I always follow the Audi recommended tire pressure. Which is 33 psi. It's shown on the driver side door edge.

Reggie

OK guys - heads up - US gov is not requiring max loading pressures be listed on the door sticker. Use your manual for the recommended pressures. Myself I use the min load pressure +2lbs.

JohnBoyToo

If these are the stock tires and wheels that came with your Q, use the door placard psi and you can adjust it a bit for comfort or performance, but that's the proper pressure.

if not the stock tires, do a google search for "the chalk test"

old school solution?
do a google search for the chalk test and it will show you what YOUR car, YOUR, Wheels, YOUR load, and YOUR tires should be set at...

configuration makes a difference and then there's that personal preference thing where, yes, I can get .005 mpg better at 80 lbs than I can @ 20 lbs, but the ride is horrible at those pressures...

the correct pressure can be a range ! YRMV

A new age solution?
get a digital thermometer and drive around and measure the temp diff between the sidewall and the center of your tire at different pressures to see what gernerates the least heat...

(or just go by your gut )

ELEVENS

I'm reasonably sure that 80psi will generate the least heat but only a fool would do that.

I also think that going from 20 to 80psi would provide more like 5mpg (1000 times better than 0.005) but again, only a fool....

No, I'm not calling anybody a fool! I just don't want anybody to actually try 80psi.

4Rook

Since you are running aftermarket wheels and tires, it will be a trial and error process. I think you are in the ball park at 32 and should give it some time to let the tires break in. Take a look at the sidewall of the tire for the load and max psi ratings. Also check the tire mfr's specs for the load at a specific psi which should be available at the mfr's website.