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Old 05-18-2012, 09:28 AM   #1
Pickler
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Default what tire pressure are you guys running

im running 36front and 33rear psi cold on 09 impreza sedan. it works great in twisty roads but i sense a bit of harshness in bumpy roads. tires are noisy when taking twisties fast but grip is adequate for amount of power 2.5i has. no understeer as well even without much throttle. tires are oem potenza re92a and my only mod is a rear sti sway bar. is there anyone else here who has found excellent pressure for auto-x or spirited canyon driving on oem tires?
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Last edited by Pickler; 05-18-2012 at 09:37 AM.
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Old 05-18-2012, 09:51 AM   #2
wurlyvalve
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You need to use a pyrometer at the least. Makes life much easier to get close, although the stopwatch is the better piece of equipment. Try going firmer on the front as an experiment. I drive a 98 legacy estate and used a pyrometer to get the temps more even. I'm running 48psi front and 40 rear, the front was running on its edges until I really cranked the front pressure up and I picked up oversteer whilst increasing it. On the other hand, my lotus 7 I run 20psi front and 8psi rear, so it is all irrelevant if there are any difference in car, tyre, driver etc.

P.s., is this in the wrong forum?
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Old 05-18-2012, 11:06 AM   #3
cmiovino
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It depends a lot on the tire too.

For example, my Hankook v12's are at 48 front, 43 rear for autocross and I've just kept them that way to even them out. I'd have to run my Kuhmo ASX's up around 50PSI front too as all the tires I buy seem wear on the outside edges if I don't. And yes, I do have a correct alignment.

Suspension comes to play too. GF210 spring, AGx struts, strut bars, and 20mm rear sway + endlinks for me.

Tire pressure makes a big difference and with any tire, I find you have to go above what the door says. I do understand I get a bit less grip with them pumped up as high as I do, but if I don't, they wear down quick.
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Old 05-18-2012, 04:41 PM   #4
Gmantanman
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You don't want to run too high of pressures for daily driving, especially if your roads aren't very smooth. It'll cause a lot of unwanted rattling and can become permanent if you run high pressures all the time. I run 34psi up front and 33 in the rear for dailying, and 37/36 for the twisties on re92s. Higher than that will give you better steering response but makes it kind of unpredictable at the limit with these tires. 22mm sway up front 19mm rear with endlinks for me.
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Old 05-18-2012, 06:08 PM   #5
Pickler
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Quote:
Originally Posted by cmiovino View Post
It depends a lot on the tire too.

For example, my Hankook v12's are at 48 front, 43 rear for autocross and I've just kept them that way to even them out. I'd have to run my Kuhmo ASX's up around 50PSI front too as all the tires I buy seem wear on the outside edges if I don't. And yes, I do have a correct alignment.

Suspension comes to play too. GF210 spring, AGx struts, strut bars, and 20mm rear sway + endlinks for me.

Tire pressure makes a big difference and with any tire, I find you have to go above what the door says. I do understand I get a bit less grip with them pumped up as high as I do, but if I don't, they wear down quick.
wow 48psi is a lot specially for a ventus as i have heard they have specially stiff sidewalls! yes i have heard of pyrometer but how would that be accurate at the track considering inner/outer sides of tire patch get warmer in corners and hence naturally cause uneven temperatures accorss tread? i do have oem springs/shocks and just sti RSB, so im thinking because of body lean i would also need more tire pressure but i was thinking 40f/36r.

yes for daily driving i use 36/33 but i did go on a track once with this and it had too much lateral motions (slipped sideways in corners). this had me thinking of even lower pressure maybe?!
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Old 05-18-2012, 06:37 PM   #6
RaceFaceXC
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guys (ladies?) there are several tire pressure discussions in the tire/wheel forum with useful, informed suggestions from people who know what they are talking about. Not saying no one here does, but it's not looking to good so far.
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Old 05-19-2012, 08:07 AM   #7
wurlyvalve
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lol, I knew my phd in active suspension was a waste of time.
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