what do you set your tire pressure to?

[MacDaddy]

I'm running stock wheels/tire size and i decided to bump things up 2psi front and rear, so now i'm at 38psi front and 36 in the rear, so far so good.

just wondering what everyone else is running and how they like it.

[S4 John]

32 in the front and 34 in the rear to reduce the understeer.

[SilverThing]

32 in the front and 34 in the rear to reduce the understeer.

^^^ x2 - works for me

[S4_NE]

41 and 40 my 235 18's they stick like glue still F1's but on stock rubber i run 34/36 ( winter mode)

[Dimcorner]

40 front and 42 rear.

[BITRBO]

just topped 'em off yesterday at 40psi front and 38psi rear (235/40/18)... gas is too expensive to be running 34/32

[wheel366]

40 all around.

[yellowbuster]

35psi all around

[Evilevo]

38f 40r Toyo T1R 225/18 on CHs

[Kruat]

36psi front 38psi rear 245/35/19 FK 452's... Works good so far.

[Quattrocket]

40/40

[Tifosi]

40F/38R on 225/40/18 or 38F/36R on stock 225/45/17

[VR4-S4]

40/40

+1

[MacDaddy]

looks like half the people set the rear higher and half the front higher, some the same.

I used to set the rear higher because some website said it reduces understeer, which it seemed to do until i went auto crossing one day and i discovered all that did was make my front tires roll over onto the sidewalls.

I find setting the rear higher helps turn in response, but not much else. considering how light the rear is on a S4 (and that i don't have traction control), i'm going to leave the rear a little flat so i can a bigger contact patch.

thoughts?

[BITRBO]

^^yeah, I was gonna ask the same thing: how come all of you guys are running less tire pressure up front where there is more weight/load??? I had heard something similar re: tire pressures for a track set-up, but I'm not sure if it applied to awd cars or not. I'm also willing to bet that 99.9% of people here don't track their cars so it seems kinda pointless to me...

36psi front 38psi rear 245/35/19 FK 452's... Works good so far.

38f 40r Toyo T1R 225/18 on CHs

40 front and 42 rear.

32 in the front and 34 in the rear to reduce the understeer.

[Dimcorner]

I haven't tracked this car, but I have the Mazda3 and the rear pressure helped A LOT (and yes, all the weight is REALLY in the front of this car).

I don't know how increasing the rear tire pressures make your front tires roll. Could it be that since the back is now sliding more you are slowing down (braking, engine braking) and transferring more of the weight up front?

On the Mazda I run 38 front 42 rear (warm).
Tires were the OEM RS-A's. Anything less than 35 and they feel sloppy.

On the Audi I have Nitto NeoGen. I haven't tracked it yet but I probably won't track these tires. The side wall is way softer because they are all-season tires. If I had stiffer sidewalls the pressure might change depending on how the car feels. Right now I have pretty neutral steering. Tail doesn't slide out, but it won't exactly plow either.

If you put more pressure up front the side walls stiffen and the contact patch get's smaller so the front would slide more. Also remember that a good chunk of the engine sits in front the the axle. So you have all the weight up front, smaller contact patch, and now you are asking the tires to pull the car sideways. The rear tires help a little, but only in going straight so no help turning, they are just along for the ride. If you are accelerating through a turn, this will transfer more weight to the back and the patch up front gets smaller. I always brake later (or engine brake) and use the throttle to help me turn the car. Not much, just small adjustments.

I think in the end it depends on your driving style and how you plan to use the car. Just remember that it changes every time. Different tire brands, road conditions, temp of the day, etc. You really can't use one set setup every time. You can start with it, and then make adjustments from there.

Personally I keep them high and I have been getting almost 23mpg combined here in Miami :(. Up when I was in Raleigh I was hitting 28mpg combined. This is using 40+psi on the tires.

[rouellettea4]

Hmmm, I usually run mine 34/34 on my oem wheels 225 tires. I guess I can be running a bit more pressure huh. Always was curious here.

[dennisS4]

40 front and 42 rear.

X2^^

[Dimcorner]

Hmmm, I usually run mine 34/34 on my oem wheels 225 tires. I guess I can be running a bit more pressure huh. Always was curious here.

Make sure you are under the max rating for the tire when it's warm.
42psi cold is not the same once you start driving so keep some overhead just in case.

[audiwop]

looks like half the people set the rear higher and half the front higher, some the same.

I used to set the rear higher because some website said it reduces understeer, which it seemed to do until i went auto crossing one day and i discovered all that did was make my front tires roll over onto the sidewalls.

I find setting the rear higher helps turn in response, but not much else. considering how light the rear is on a S4 (and that i don't have traction control), i'm going to leave the rear a little flat so i can a bigger contact patch.

thoughts?

You are right on this one... I track my car at least 4-5 times a year and have tried tons of different settings. I have come to the conclusion that our cars handle way better buy running more pressure up front. Right now I went for a drastic setup and it's working very well (front set at 36psi cold, rear set at 31psi cold). I know this looks insane, but for those of you who try it, I think you will come to like it....

[Bee Five]

+1

x2

I run 40f/40r psi on all my cars, best combo for fuel economy and even tire wear

[MacDaddy]

I haven't tracked this car, but I have the Mazda3 and the rear pressure helped A LOT (and yes, all the weight is REALLY in the front of this car).

I don't know how increasing the rear tire pressures make your front tires roll. Could it be that since the back is now sliding more you are slowing down (braking, engine braking) and transferring more of the weight up front?

I wasn't meaning that increasing the rear tire pressure increased front tire roll (thats how it sounded, i know). what i meant is not inflating the front tires really high allows them to roll over onto their sidewalls, i could have been more clear there, my bad.

anyway,
despite the fact higher front tire pressure moves the contact patch more to the center of the tire, my grip is far better in a corner as the contact patch shifts from the side and middle of the tire instead of entirely to the side/sidewall.

next time you track your car, try setting the front higher and you'll probably have to set the rear proportionately lower to balance things out. what your looking for is the little arrow on the side of the tire pointing outwards to the tread, you don't want to see any tire wear above or below the tip of that arrow. Once you get it in that sweet spot up front, experiment with the rear tires to find what works best.

[Dimcorner]

I wasn't meaning that increasing the rear tire pressure increased front tire roll (thats how it sounded, i know). what i meant is not inflating the front tires really high allows them to roll over onto their sidewalls, i could have been more clear there, my bad.

anyway,
despite the fact higher front tire pressure moves the contact patch more to the center of the tire, my grip is far better in a corner as the contact patch shifts from the side and middle of the tire instead of entirely to the side/sidewall.

next time you track your car, try setting the front higher and you'll probably have to set the rear proportionately lower to balance things out. what your looking for is the little arrow on the side of the tire pointing outwards to the tread, you don't want to see any tire wear above or below the tip of that arrow. Once you get it in that sweet spot up front, experiment with the rear tires to find what works best.

I wouldn't be surprised if this is the case. Every car is different and every tire will act different too. Once I get the turbo's done I'll probably hit up a AutoX and test out pressures.

[BITRBO]

This is some good dialog guys! I can see that running even more pressure up front than the rear (greater delta) for a track setting might be very complementary to our car's natural short comings. I'm def. gonna try it when I hit the track soon (*knocks on wood*).

But during the week and around town, you should probably run F&R a little closer to one another, with no more than 38F/36R cold IMO. Since there is a more weight up front and less in the back, running reverse pressures (i.e. 36F/38R, or worse) is sure to wear the tires unevenly: the fronts will wear more towards the outside edges, leaving the center "unused"; and the rears will wear out the center, leaving the edges unused. Now combine that with prolonged unbalancing, tire rotations, and/or alignments and you're bound to get feathering, cupping, or crap that will wear out a tire real fast...

After installing countless of tires for PepBoys in my youth, and checking/adjusting tires pressures for clueless customers, I can honestly say I've seen it all I will agree it all depends on the tire brand, compound, side wall height & stiffness, climate type, driving habits, etc., etc.. So many variables, but pressure is the most commonly overlooked one.

[BITRBO]

I wouldn't be surprised if this is the case. Every car is different and every tire will act different too. Once I get the turbo's done I'll probably hit up a AutoX and test out pressures.

hey man, you mentioned you get 23mpg around Miami? What are do you frequent, cause I'm in Coral Gables... Not sure if you attend any of the meets, but I hardly see any B5's

Let me know if/when you hit the track next time.

[DraxeofDclan]

Good thread! 32psi front 34psi rear. (for track) max psi for long distance travel to obtain optimal MPG. I run higher psi in the rear to allow the rear end to slide out. This helps in control for aligning the car in turns. Otherwise it will keep going in the same direction even though you turn the wheel. "Sipped" Toyo Proxes 4

[vladbe]

42 psi all around.

[AUDILUX]

So, some of you are saying front tire pressure should be higher for better handling (due to higher weight load on the front tires) and some of you are saying that rear tire pressure should be higher for improved handling (in order to decrease understeer/create oversteer). Which one is it??

[S4 in_lowplaces]

lol

[Dimcorner]

hey man, you mentioned you get 23mpg around Miami? What are do you frequent, cause I'm in Coral Gables... Not sure if you attend any of the meets, but I hardly see any B5's

Let me know if/when you hit the track next time.

I live up in Pines, but my parents live in Sweetwater right next to FIU so I go down quite often. I tried to go to a meet last time but now one showed up (Tropical park at 2:00pm or so on a Sat.). When is the next meet?

As for tires...

I believe that I ran 38 front 36 rear on my RX7 because it was too tail happy (I also set the struts to max on all 4 corners, Yokahama tires). I went back to stock size with BFG KDW's and had to increase rear because the car would now plow.

Yeah there are a lot of variables. If you are just driving every day and not really trying to get around a track in the shortest time then as long as you are at least the recommended pressure you should be fine. Otherwise you will just have to experiment and get a few runs in.