JohnEnglish

Out of season, yes, but I was thinking about this over the weekend.

I have a RS5 with 275/30 R20 summer tires. The user manual recommends 36 psi front and 33 psi rear. I got the Audi winter tire package from the dealer which came with 235/40 R19 tires on the 19"Audi Sport wheel.

I asked Audi corporate (Europe and US) what they recommended and they both came back with "Ask your dealer". The dealer said 41 psi per tire which is the recommended pressure for the summer tires at maximum cargo capacity. i know the general rule of thumb is winter tires are inflated 3 - 5 psi higher than summer tires, but that's for identical sized tires. Since these tires are smaller I'm wondering if I could get away with the same pressures.

DaveSNJ

rule of thumb - go by the tires load index rating #. A higher load index than the OEM standard = lower pressure. A lower load index # = higher pressure. Use the chart in the owners manual for real recommended pressures.

if we could attach files I could post the chart

JohnEnglish

The OEM tires have a load index of 97. The winter tires I got have a load index of 96. So that looks like it's 1,609 lbs (OEM) vs 1,565 lbs (winter).

DaveSNJ

Whoa - 1609 is at 42psi - way too high.

At recommended pressure 36/33 the carry capacity is 1423/1319. To duplicate that in a 96 load index tire you'd want to run 38/34 or 38/35

Yoshimura

You also need to take into account tire speed rating. Lower speed rating could need higher pressure. So better to check owners manual.

JohnEnglish

Thank you

mhoran89

If this helps you on my S5 cabriolet I am running 39f/37r on 255/35/19 and it is working well for me so far. As previously mentioned, 42psi is too high for anyone doing any sort of normal driving....
I was running 38f/36r on 245/40/18 all-seasons during the winter months... and that worked well too....