Tire pressure tips

[EKam]

This sounds a bit logical to me so I'm posting this here.

This was given to me by CamryMan.org user "cdssolara" and it is the best formula for tire pressure that I have read.

Take your vehicle weight plus driver and divide by 100, this is your base.

Add 2psi to that if you have a OE suspension.

Add 2 more psi on the heavy end of your car (front for our cars)

So you say that you car weighs 3400lbs that means 34lbs is the base, so for a Camry with stock springs 38 front 36 rear, with a performance springs it is 36 front and 34 rear ...

Play with it from there to suit your taste. more pressure for performance driving and less for driving grandma to the store.

[Xenon]

That sounds very reasonable actually... Thanks elegantcam, I'll use that formula and maybe I'll notice a difference...

[Deep]

What do most of you guys run on the street and what kinda car/suspension mods do you have?

[DaksGT]

And add 4 more on top of that

[Xenon]

My friend was telling me today that 32psi is too low for my Toyo Proxies! He apparently used to put 38psi in them to get the best performance!

[86CRESSIDA86]

i put 40psi in my potenzas, gives a nice firm ride, but still grips well and the tires last a good time

Ian K

[cdssolara]

I just joined this forum recently, and I see I got credit for the formula in the first post!

Anyway, the formula is just for a basis point. A lot of people who like to drive fast will probably want to up the pressure a bit. It will keep the tire a little stiffer and provide quicker cornering. Most autocrossers like to keep the pressure higher than what is recommended by the tire manufacturer. For drag racing, you want it lower.

[NASTY]

shouldnt the pressure be the same regardless of tire?
i always thought that upping it more than 32-33 (toyotas reccomendation) would cause the center wear quick

[cdssolara]

For normal driving, the recommended pressure is probably OK. Increasing the pressure a few psi is probably not going to cause any noticeable difference in how the tires wear. At the recommended pressure, however, the handling will probably feel pretty "sloppy" during aggressive driving because the tires will be a bit soft for quick turning. In an event like an autocross, you'll be putting a lot more pressure on the edges of your tires than you will on the center.

[daidaikonnootoko]

Wow, that's really good information to have! Thanks cdssolara
I never really thought of it in an organized formulaic sense.

Right now I'm running Yokos at 41psi back and 44psi front (little more psi than normal) but I don't know if my gage is completely accurate. Regardless, the handling/cornering is excellent compared to what they used to be (32 and 31ish). Feels good.

[cdssolara]

How's the ride comfort at that pressure? Is it noticeably firmer?

[rolla1997]

yeah on my rolla i put the pressure at 34 PSI on my stock tires. Had them at recommended 30 psi and way too much roll around corners cuz stock suspension is really soft.

[superpilun]

I'm not sure I agree that the heavier end should be inflated more. In ff cars, the front tires do a lot more work so they heat up more, this usually means that during competition you need to lower the pressure some so that when the tires get to operating temperature, you have optimum handling. More pressure does not mean better. The pressure should be such that during competition, the temperature across the tire (inside, middle, outside) is the same. If over-inflated, the middle of the tire will be hotter, and you are not using the tire to its full potential. If the inside is hotter, you have too much negative camber. And so forth. The only real way to know if you are at optimum pressure is to get a tire pyrometer (temp. gauge). However, sensitive drivers can tell the difference between an under-inflated understeer and an over-inflated understeer in FF cars. Go read up on www.turnfast.com it's an excellent resource.

[Xenon]

Your advice is great, but you don't want ober inflate your tire to the point wehre the car starts skipping on the smallest bumps. I cannot have my tires over inflated because I have a very stiff suspension, therefore if my tires were very stiff I'll have an unbearable ride!

[Tex97]

I'm running 35psi on my Goodyear Aquatread 3's(They suck, but they are brand new-came with the car) and stock suspension.
I was running 32 but it was too sloppy for me, 35 seems like a good mix of road feel and comfort.