air retention -- how well do tires retain psi?

[forestir]

I was wondering if others have the same "problem" I've been observing: no matter what I'd like my tire pressures to be, say 35 front, 33 rear, over the period of about a week, they leak down to about 32/32 and will then stay like that.

 

It seems there's a max pressure they'll leak to, and then be able to retain that pressure. This is with consistent 100F daytime highs and 80F evening temps in Texas. I'm measuring cold, at about the same time of day.

 

I know many of you like higher pressures (as I'm experimenting with), but do you have to check and fill up frequently?

[intercede007]

I was wondering if others have the same "problem" I've been observing: no matter what I'd like my tire pressures to be, say 35 front, 33 rear, over the period of about a week, they leak down to about 32/32 and will then stay like that.

 

Unless you are going for a tad bit better gas milage, the door panel on my '05 LGT Wagon says 32/30. It seems as if your car is trying to do you a favor

 

But no. While I've only had my LGT for a week, I put air in them last Saturday (the **** dealership had them at 22/20!?!?!?!?!) and checked them today; still 32/30.

 

Wierd

Jon

 

EDIT: Just noticed you have an Outback XT. Disregard

[forestir]

Outback XT door panel recommends 32/30 as well--same as the Legacy GT. I was just playing around with pressures to tune the ride/handling a bit.

 

The air pressure thing's not unique to this car. But I'm curious if others have to attend to their air pressures often, especially when inflating to higher pressures all around.

[melayout]

My LGT sedan door panel says 35/33 cold tire pressure.

[Xenonk]

are you reading hot and cold pressures? A tire can cool down and drop as much as 7 psi overnight after a hot drive..

[outahere]

Unless you are going for a tad bit better gas milage, the door panel on my '05 LGT Wagon says 32/30. It seems as if your car is trying to do you a favor .....................

 

I have the same vehicle, and the recommended pressures on the door decal are 35/33.

[mwiener2]

He's not asking about recomended pressures. Many of us have noticed that the RE92's perform a tad bit better with higher pressure. His problem is that everytime he pumps them up, they leak out in about a week.

 

 

I pump mine up to about 37f 35r. It stays that way. The tires still suck though.

[forestir]

I'll pump 'em up again to 35/33 (door panel recommends 32/30 for OB-XT-wagon) and try to be more consistent with temperature when I do the pumping and reading.

 

If they still leak down, maybe I'll complain to the dealer or something since it's critical that we maintain rolling circumference within 0.25"... a drop in pressure would kill my diffs. (I guess I'm only half joking on that point.)

[emlevins]

I've had two sets of tires on the car and both dropped about 2psi per week while reading cold.

[jaycee]

I have Pirelli PZeroNero M+S tires on my wagon and try to keep them at the recommended 35f/33r but they also seem to leak down to about 30psi and stay there. Maybe it's the aggressive cornering I do or something to do with the geometry of the rim? Hmm.