Tire pressure on 255/35/19

[Amm4]

Hello,

I just put on S5 wheels 255/35/19 advan S.4. on my 2011 audi 2.0T quattro. I searched on google and forum, as well as looked into owner's manual. I've decided to go with 34psi in the front, and 33psi rear. I'm no expert in tires, but it looks flat... Here are some pics:







Is this what its suppose to look like? If not, what tire pressure should i run? Thanks!

[sickspeed]

i think most people run a little higher than that, i.e., 35-40 psi. as for how it looks, i see what youre saying and i have the same tire specs on my stock s-line wheels but i think its probably a matter of the tire being somewhat wide or square for the size/width wheel. im guessing those wheels are 8-8.5" wide? if so, 255s might just be a bit meaty for that size wheel and causing the "flat" appearance youre referring to.

[coolwater]

38 front and 42 back is from factory.
Dealership did 41 front and back on my last rotation.
You are currently way too low....

-cW

[gunsmoker]

38 front and 42 back is from factory.
Dealership did 41 front and back on my last rotation.
You are currently way too low....

-cW

The factory sets a high pressure for a different reason. 38/42 is way too high. The wear will tell you if certain pressures are too high or too low for your average load and driving conditions.
I run my 18" at 34/34 and haven't needed to rotate the tires for my 23k miles (mine is a quattro) and the wear is even front to back, side to center.
The mid point between the full and normal load settings in the manual is always a good place to start. You can give it 1PSI up if the roads where you live are not great.

[coolwater]

You are comparing 18's to 19's.
The reason why the dealership service dept puts 41psi all around is because that is what is recommended on the door jam.

-cW

[dscline]

My '11 Avant with s-line package came stock with 255/35/19, and the sticker on the door says 38 front 42 rear. That's obviously for a fully loaded car, but is at odds with the 35F / 35R recommended in the manual for fully loaded. FWIW, I do 39 all around, as it's generally a couple psi low by the next time I check.

[jbradle7]

38 front and 42 back is from factory.
Dealership did 41 front and back on my last rotation.You are currently way too low....

-cW

This is what I run as well.

[jbradle7]

I'm no expert in tires, but it looks flat... Here are some pics:

as for how it looks, i see what youre saying and i have the same tire specs on my stock s-line wheels but i think its probably a matter of the tire being somewhat wide or square for the size/width wheel. im guessing those wheels are 8-8.5" wide? if so, 255s might just be a bit meaty for that size wheel and causing the "flat" appearance youre referring to.

Visual appearance is a terrible indicator of a properly inflated tire, always use a tire pressure gauge to be safe.

[hiwords1]

idk what tire you have but i'd run at least 39. you want more air in your tires since you have less sidewall. it'll help absorb some of the shock over certain bumps

[gunsmoker]

You are comparing 18's to 19's.
The reason why the dealership service dept puts 41psi all around is because that is what is recommended on the door jam.

-cW

I wasn't comparing 18" with 19", but it's beyond me why the pressures at the door are so high, given the reasonable numbers in the manual. What I meant was that the factory overinflates the tires to avoid flat spots before the sale.

[Amm4]

i think most people run a little higher than that, i.e., 35-40 psi. as for how it looks, i see what youre saying and i have the same tire specs on my stock s-line wheels but i think its probably a matter of the tire being somewhat wide or square for the size/width wheel. im guessing those wheels are 8-8.5" wide? if so, 255s might just be a bit meaty for that size wheel and causing the "flat" appearance youre referring to.

I'm running on 255/35/19 on 19x8.5 S5 wheels

[Amm4]

Thanks guys! I've decided to go with 39psi front and rear. Will post pics later to compare the visuals.

[coolwater]

I wasn't comparing 18" with 19", but it's beyond me why the pressures at the door are so high, given the reasonable numbers in the manual. What I meant was that the factory overinflates the tires to avoid flat spots before the sale.

I also questioned this when I switched from 18s to 19s.
The consensus from everyone including the service dept was to run it higher.
Helps with stiffening side wall and protecting wheels...

Anyway looks like OP has his answer.

-cW

[typer100]

Thanks guys! I've decided to go with 39psi front and rear. Will post pics later to compare the visuals.

Always around 38 for me. I'm getting older and sport suspension is already stiff enough...

[Big Nodge]

Curious why people run even f/r pressure if factory recommends higher psi for rear? I have 255/35/19 and run 38/42 per door sticker. I was psyched to see the rear bias as I figured it was meant to compliment the 40/60 f/r torque split on the B8s awd system, and the weight distribution (battery in trunk, etc). Split was 50/50 on my B5 and B7 and the B8 is def the most fun on back roads.

I guess for tire wear, but I rotate at winter swaps and that seems to be enough for my wear to be fairly even, so far.

[Amm4]

After driving around with 39f/39r, i felt a lot of road, I switched it to 37f/40r and the ride is much smoother.

Here is a pic of my fronts (top pic 33psi, bot pic 37psi). I tried to get it at the same angle, but there is a noticeable difference between the two in person.

[dscline]

Curious why people run even f/r pressure if factory recommends higher psi for rear?

Because the higher rear numbers are for full load conditions i.e. rear seat full of people and trunk full of cargo. If you look in the manual, it actually recommends slightly higher pressure in the front under "normal" load conditions, because the car does have a slight front weight bias. That shifts to the rear under fully loaded. The door stickers seem to only list the fully loaded pressures, probably just to be safe. I run even front/back as a compromise, since it's usually just me or 1 passenger, but I occasionally have rear passengers or cargo. If I were going on a road trip with 4 people and luggage, I would bump up the rear pressures.