What tire pressure are you running?

[riceboy22]

I'm just wondering what tire pressure people are running. I know we have a lot of different setups out there, so if you feel it's worth highlighting, feel free to add in the comments. I'm running 275/40r20 and aim for 38psi (although I appear to be way off that from the alignment I just had done).

Edit: It appears polls don't show up in Tapatalk.

[B_Boy]

36 psi for 265-35/22 tire on 22x10.5 wheels

[Resoom]

39 psi on 275/40R20 on 20X10 wheels

[NYSpeedRacer]

I'm actually running

265/40/21 F
295/35/21 R

@ 40psi

I think mop had it at around 43psi originally.

Sent from my Rickshaw

[BarryT82]

Mine has the factory 20" peelers. The door label shows 29psi, but it rides like crap at that. The manual shows that the SQ5 with the same size wheels and tires should have 39psi. I called Audi customer care to ask what the difference was and they couldn't tell me. I looked up the curb weight and the Q5 TDI is a little bit heavier, but not by much.

[riceboy22]

Mine has the factory 20" peelers. The door label shows 29psi, but it rides like crap at that. The manual shows that the SQ5 with the same size wheels and tires should have 39psi. I called Audi customer care to ask what the difference was and they couldn't tell me. I looked up the curb weight and the Q5 TDI is a little bit heavier, but not by much.

I think the difference is primarily driven by the maximum speed for each car, and ultimately I'm sure by the associated liability. The recommended tire pressure needs to support the maximum speed for the car. The reality though is that's not going to be particularly applicable to most of us given where and how we drive.

[DannyDeez]

Bumping this thread instead of creating a new one. I was wondering what you 20" wheel guys were running since the door jamb in the wifes Q5 only shows pressure for the stock 19's.

Im also surprised to see it listed so low at 33psi when my S4 calls for 41psi. Can anyone tell me why its like that? Shouldn't the bigger, heavier car need more pressure to support the load, or do I just have no idea how this stuff works?

Thanks!

[NYSpeedRacer]

Bumping this thread instead of creating a new one. I was wondering what you 20" wheel guys were running since the door jamb in the wifes Q5 only shows pressure for the stock 19's.

Im also surprised to see it listed so low at 33psi when my S4 calls for 41psi. Can anyone tell me why its like that? Shouldn't the bigger, heavier car need more pressure to support the load, or do I just have no idea how this stuff works?

Thanks!

I'm at 40PSI for my 21s


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[q5 dave]

38PSI on my 21's

[riceboy22]

@DannyDeez, for reference, here are the tables from the manual (stolen from AW):




If you're looking at the door jamb, I believe it only shows the full load pressure. The recommended pressure under normal conditions is lower. I think people sometimes mistakenly assume that running a higher pressure (and the associated ride discomfort) equates to better performance. There's a point though where all you're doing is reducing your contact patch to sub-optimal.

I haven't gotten around to chalking like others have suggested, but I'm currently running 36 psi on my 275/40R20 setup. For wider tires of the same diameter, my understanding is you'll generally want to run a lower pressure than the equivalent narrower tire.

Edit: I mentioned this earlier in the thread, but I think the higher pressure recommendations for the SQ5 are partially based on the higher maximum speed. I may actually try dropping my pressures even a bit more.

[DannyDeez]

@DannyDeez, for reference, here are the tables from the manual (stolen from AW):




If you're looking at the door jamb, I believe it only shows the full load pressure. The recommended pressure under normal conditions is lower. I think people sometimes mistakenly assume that running a higher pressure (and the associated ride discomfort) equates to better performance. There's a point though where all you're doing is reducing your contact patch to sub-optimal.

I haven't gotten around to chalking like others have suggested, but I'm currently running 36 psi on my 275/40R20 setup. For wider tires of the same diameter, my understanding is you'll generally want to run a lower pressure than the equivalent narrower tire.

Edit: I mentioned this earlier in the thread, but I think the higher pressure recommendations for the SQ5 are partially based on the higher maximum speed. I may actually try dropping my pressures even a bit more.

Thanks for the post! The 20's I just put on her car are the OEM size 255/45/20 and they're currently set at 36psi.

The door jamb shows 'cold tire pressure' which I can only assume means the pressure after the car has sat overnight (or at least a few hours) without being driven?

Here's a pic of the door jamb:



So the manual shows full load as being 33psi, but the door jamb shows cold pressure as being 33psi.
I'm guessing since a lot of guys are running a general range it doesn't matter too much, but does anyone know which is correct?

[riceboy22]

So the manual shows full load as being 33psi, but the door jamb shows cold pressure as being 33psi.
I'm guessing since a lot of guys are running a general range it doesn't matter too much, but does anyone know which is correct?

They're both correct really. Recommended tire pressures are given as cold pressure, so that basically means the car hasn't been driven recently and the air inside the tire is the same as the ambient temperature. The door jamb for legal reasons shows only the full load pressure; the owner's manual is allowed to have both the normal and full load pressures. Those are all cold pressures though.

I'm at 36 psi as well, so I'm a little below the recommended pressure for the SQ5 on stock 20s, but I'm also running a wider tire. I'm planning to drop it down a bit to maybe 34 to see how much it improves ride comfort. I'm ok with a little more squishiness in exchange for a softer ride during daily use.

[DannyDeez]

They're both correct really. Recommended tire pressures are given as cold pressure, so that basically means the car hasn't been driven recently and the air inside the tire is the same as the ambient temperature. The door jamb for legal reasons shows only the full load pressure; the owner's manual is allowed to have both the normal and full load pressures. Those are all cold pressures though.

I'm at 36 psi as well, so I'm a little below the recommended pressure for the SQ5 on stock 20s, but I'm also running a wider tire. I'm planning to drop it down a bit to maybe 34 to see how much it improves ride comfort. I'm ok with a little more squishiness in exchange for a softer ride during daily use.

Ah ok, makes sense. Thanks for the info. The wife hasn't complained about ride quality, and it still feels fine to me so I might as well leave it where it is.
I was just afraid that the pressure was too low given that my S4 has 41 listed on the door jamb.