GeriatricSQ5Guy

A few months ago my summer tires were ready for replacement, so I bought a set of Michelin CrossClimate II, 245/45/20. The tires ride a good bit rougher than the old Michelin Latitude summer tires, presumably because the rubber and the sidewalls are harder. But at least I can drive the car now in colder winter temperatures without worry.

The manual says 36F/33R for driver and 1 passenger, regular suspension. Would it help to lower the pressure some? Hopefully someone with the CrossClimates can chime in.

ColoradoSpringsAR

I have CC2 on my 18 Q5 and I'm running them at 34/34 right now.

rdA4WtQ5

Did you miss type 245 or miss buy your new tires? 255/45-20 is the standard size. Close, speedometer is now reading a slightly faster speed than actual if 245. And air pressures in the manual are not 100% valid and you may need a few more PSI.

GeriatricSQ5Guy

More a matter of misremembering than mistyping. I was going by memory and got it wrong.

Wires

I was just running the OEM door pressure (same tire size as the car was delivered with).

Wantboost

I hate them !!!! Killed the ride quality. I've lowered pressure 3psi all around helps a bit.

SMac770

Not sure Canada's regulations, but Audi in the US only puts the full load recommended pressures on the sticker. You have to look in the owner's manual for more complete inflation information. Though if you regularly carry around 4-5 people or stuff or tow, then full load it is. I am 95% of the time the only "payload" in my car, so I run the partial load pressures.

Even then, you have to use some thought to what's behind the numbers (such as running 170mph pressures when you'll never break 120mph).

Look at the MY18 Q5 owner's manual.
The 255/45r20 101W line is for the Pirelli Scorpion Verde 101W SL AO summer tire - https://www.pirelli.com/tires/en-us/...-r20/101w-audi
The 255/45r20 101H line is for the Pirelli Scorpion Verde All Season 101H SL AO tire - https://www.pirelli.com/tires/en-us/...-r20/101h-audi
(they use others like Michelin Latitude Sport 3 101W SL for the summer role, but I couldn't determine which Michelin A/S they might use, if any, for the comparison)
So what about those dictate a +3 psi increase under partial load and a +5 psi increase under full load for the summer tire? They are both 101 SL tires on the same vehicle. Is it simply catering to the response expectation of someone using "performance" tires?

So be at least 33/30 for partial load or 36/36 for full load. Beyond that, it's about your own call on comfort vs mpg vs response vs even tire wear. And whatever you work out for your tire, it's starting over as soon as you change the make/model/size/index to something else. Dan99 had posts discussing those sidewall markings as well regarding pressure vs tire roll; it's an interesting read as well.

Wires

User manual in the glove box states "correct ire pressure is shown on the door jam sticker" with a cartoon of the door jam sticker. It's what I've used for years, and have always gotten even tire wear across the tread. The sticker would only be applicable for the tire size/tire style as delivered with the vehicle though.

SMac770

Good for you? If you read the next sentence in the manual, "Use the tire pressure specified for a normal vehicle load when the vehicle is partially loaded => table on page 337."

Wires

And the next line below that says "if you exceed the partially loaded recommendations, you must use the full load recommendations". Partially loaded is "3-people". Thanks Audi, what does that even mean? 3, 150lb Europeans, or 3, 250lb North Americans? It's the most useless table on the planet. Why not spec a weight if you are going to use "load" as your inflation guidelines.

BMW spec's theirs as a loaded weight under 100mph, and a loaded weight above 100mph. Nice and easy to understand.

What happens when running the lower pressures and you decide to wind it out on a secluded backroad?