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Subject says it all.

I've had my WRX for about two months now. I recently decided to check my tires. I noticed the pressure in all the tires was around 30psi. I'm not sure if the dealership did this or if they ever checked the air. The max printed on the tire is 44psi. I filled them up to around 40psi.

The ride feels a little harsher, but I'm not sure if I can tell. Might be psychological. What psi do you guys recommend using the stock tires at? Any seasonal recommendations?
 

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On the frame of your driver-side door, about where your elbow would be if you were in it, there is a small sticker giving recommended tire pressure. I believe it's 32 psi front and 29 rear.
 

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Thanks Bedabi for the reference, I was wondering that too.
BTW, pending on ambient temps, here in MI, I've found my tire pressure to change 3-5 psi between cold and driving temp.
 

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Ah, that's what the manufacurer recommends but not neccesarily the best for handling.

Here's a search with some threads on the subject.

http://www.clubwrx.net/forums/searc...d=100112&sortby=lastpost&sortorder=descending

You'll find recommendations of 38-40 front, 34-36 rear depending on how you want the car to handle. I run 40 front, 36 rear. Also see the suspension tuning table in the Technical Reference thread at the top of this forum.

Those are cold tire pressures. Well, I guess cold is around 70 deg, so if it's 20 go a couple of pounds less! ;)

Chris
 

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Careful, putting too much air in there may not necessarily help your traction. Putting more air in may help keep the car from sloshing so much and the tires from rolling off in an extreme corner, but it may also lessen your contact area.
 

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Good point. What you really want to do is find the optimal pressure that gives you the most grip. This has to do with sidewall stiffness, slip angles, etc. The scientific way to do this is to measure the temperature across the tread with a pyrometer. Find the pressure that gives you even heat across the tread. Then adjust one end or the other to tune the handling. For tires of the stock size this seems to be between 36 and 40psi. The rears are backed down a bit to dial out some of the understeer.
 

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i filled up my tires w/ air at a gas station near the 1/4 - after the 1/4 i drove back to adjust the pressures again, and when i checked them, the fronts were at a whopping 51psi!!!! damn houston summers, you really hafta watch how much air you put in there - anyways, moral of the story is that whenever you race or goto the track, your psi's go up alot more than you think
 
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