Tire pressure

[evolved13]

OK guys and gals-
What is the optimum air tire pressure for an MR evo X, with stock suspension, tires and wheels?
This would be based on it being a DD and wanting a balance between good handling and tire longevity. Â*Evo 8 and 9 owners please chime in as well. The assumption is it has a stock (from the dealer) alignment. Thanks. 8)

[kambodianboi]

On the driver side door, there should be a label with all that info. Usually 32-35lb for tire pressure. But can always defer depending on what tire brand.

[tryme_4g63]

read the tire it stats a cold pressure go with that

[I like to Smash]

^^tire does not show you cold pressure. It shows maximum psi for the tire.

PSI shown on the door panel is for comfort level. If your a spirited driver, fill about 3-5 psi more than psi shown on the door panel.

[Rencii]

^^tire does not show you cold pressure. It shows maximum psi for the tire.

PSI shown on the door panel is for comfort level. If your a spirited driver, fill about 3-5 psi more than psi shown on the door panel.


question... why would you put more air in the tire for spirited driving? just curious what the logic in that is, not bashing on you at all.

I'm curious because (and i really am most likely wrong) the way i think about it, if you fill up a tire with more air, you increase the roundness of the tire, and lower the rolling resistance. Hence the reason people put more air in their tires to get more MPG.
However... if you let out air out of a tire, you get a slightly larger contact patch with the ground due to the tire being less round, which would then increase the amount of grip at the limits. Of course... only to a certain limit, because if you let out all the air you would end up with a ruined tire.

[kambodianboi]

@Rencii, your point is true, but it also depend on the tire size (ie. 255/35/17, etc) which the width of the tire is pretty much consistent contact to the ground even at high PSI. But if you run narrower tires like 225/45/17, its rounded.

Also more air in the tire, basically make it more stiffer/firmer, allowing it to respond better on turns.

[BudLightMike]

i like to check the tire preassure!!!

[AlphaKennyBody]

I heard that there's a few guys out there that track on NT05s notice a better feel and lap times with more air in their tired than less... It was talked about in the Vette, and Bimmer forums.

[Rencii]

mmm thanks for the clarification kambodianboi. I came from a subaru, and only had the evo since sept so going with big wide tires is a bit new to me. The widest tire i've ever run on my subaru was 235/45R18 and from that experience is where i was speaking from in my first post. i could understand how if you had a very wide wheel having more tire pressure is better because it would allow for a more even contact patch.

[EvoBaja]

ive teched on teams from dragsters to class 7 off road trucks

tire pressure is so important and different based on every element

weather, condition of road (or dirt), weight, desired result, and wall height of tire.

[I like to Smash]

mmm thanks for the clarification kambodianboi.Â* I came from a subaru, and only had the evo since sept so going with big wide tires is a bit new to me. The widest tire i've ever run on my subaru was 235/45R18 and from that experience is where i was speaking from in my first post.Â* i could understand how if you had a very wide wheel having more tire pressure is better because it would allow for a more even contact patch.


As well as stiffening sidewalls and giving you unwanted sidewall flex during spirited driving. Plus, filling up 2-5lbs more than oem specs wont effect your contact patch unless your on a road course lap after lap constantly heating up your tires. Ive auto crossed many times in my old car (subaru wagon that could) as well as in my X and inflating your tires 2-5lbs above your normal oem spec, helped dramatically. Especially when your not on R-comps and using a Street/Summer tire.

As for road course tire pressure, we leave it at normal psi, after a few laps, check the psi to see where its at. then you adjust accordingly. If you fill up your tires above oem specs, then your asking for over inflation and a scary ride around the track.

PSI also reflect understeers, oversteer etc etc. That would be a another discussion.

[wrctuner]

that makes sense. just follow whats stated on the door, i sometimes add a little more psi as well.