TruPlaya26

iTrader: (4)

Ok first of all I've got Bridgestone Potenza RE050 tires size 225/50/16 on my '01 GS430 ...

The last time I took it to the dealer they filled the tires up with nitrogen to 38 psi saying that this is how much Lexus recommends to fill them, this morning I went out to fill my tires since I knew they had to be a little low and I noticed that on the tires it says that the maximum is 51 psi ...

So I was wondering what I should do? My tires were around 34 psi when I checked this morning and I filled them to 45 psi which I thought is a good number since it's right between the number the dealership gave me and the number on the tires ...

So should I take them back down to 38?
Leave them at 45?
Or fill them up to 51?

Thanks in advance

sirblinks

iTrader: (2)

i cant remember exactly what my psi's are...but i think it was 51psi..and i was told to fill it up between 40-45. if you fill it up to the max, i heard its not good for your tires

pingu

Wow thats a lot more then what I do. I just go with what it says in the door sill.

4ntvings

iTrader: (6)

iirc, the amt on the tire is at cold temps.
i've never used nitrogen to fill mine...just use the natural resources given to us...36-38psi here.

TruPlaya26

iTrader: (4)

So it's best to fill it up slightly below the max level? (max on my tires is 51 and I'm at 45)

And btw yes, this was measured and filled in the morning, after my car had been sitting overnight, so this was cold temp. ...

sirblinks

iTrader: (2)

i say leave it at 45. thats what im on right now. just dont get too close to 51. ha ha. i think to be safe, 43 would be good.

PushinLEX

iTrader: (9)

my tires are chillin at 40 psi.........

98GSOwner

If you have factory rims and tire size, I would go with the factory rec. (doorsill or owner's manual). I know my 98 GS4 shows 32psi for the 16" wheel and 33psi for the 17" (those are cold psi numbers, certainly not after a drive). Aside from the safety issues of overinflating, you will wear out the center of the tire tread if you run too high a pressure. I would start with factory recommendations and then watch your tire wear and adjust accordingly.

sleeper408

iTrader: (6)

45 psi is very high. I'd take down to 36 to 38 psi.

45 psi cold will move up a few psi after the tires are warm. You don't want over-inflated tires.

sirblinks

iTrader: (2)

sorry just checked my tire pressure, they're at 40. bring it down to 40 oops!

Ckroush

I don't know what you guys are talking about. I've never heard of inflating them to 40psi and above. I've always been told by every dealership and body shop to go with the pressure that's in the door. And if you don't know the recommended pressure, 35psi is always right. Most places I've taken my cars to inflate to 35, regardless of what the door sill says.

Plus, over-inflating will make the ride a lot rougher, and wear out the center tread. Under-inflating will reduce gas mileage and wear out the outside edges of the tires. I stick to 35psi no matter what car I'm driving.

mitsuguy

iTrader: (2)

All passenger car tires carry their max weight at either 35, 36 or 41 psi, depending on the style of tire... p-metric, 35; euro-metric, 36; and XL at 41 psi...

The main reason for air pressure is for weight carrying, so, if you go above those numbers (again, depending on the type of tire you have), you are not gaining anything in terms of weight carrying, or rim/tire protection...

The reason that tire manufacturers have a max pressure on the side of the tire that is higher than the pressure at which max weight is carried is so that you can tune the performance of the tire... In performance applications, some tires will tend to roll over at lower pressures, so, tires are chalked, and pressures adjusted to keep from this happening, yet kept low enough to provide better traction at the same time... it's a delicate balance, and the manufacturers have already given you a starting point for OEM sizes - it's on the door placard of every vehicle...

higher pressures can unnecessarily cause a rougher ride and wear the center of the tread faster, they can also lead to easier tire damage when hitting potholes (coincidentally, lower pressures can lead to the same)

TruPlaya26

iTrader: (4)

Ok well i guess I'll be dropping my pressure tonight to around 40 psi, crazy enough though, I'm at 45 psi right now and the ride felt smoother ...

BigWaveSC

iTrader: (5)

so I have a 18-19 inch staggard setup.

225-40-18
245-40-19

what pressure should I run?

car is completely gutted and setup for drifting.

mitsuguy

iTrader: (2)

there is no tried and true pressure...

real racers chalk their tires and look at rollover on the shoulders...

basically pick 4 spots around the diameter of the tire, and use tire chalk to color the sidewall and rollover onto the tread a little bit... go out onto a course with rough estimates of tire pressure, 35 psi a good place to start, and drive it 9/10's.... when you get back, look at how much of the chalk is gone - ideally, the tire should roll over enough to let the entire tread hit the road on the turns, but not onto the sidewall at all... every tire has a specific tread / sidewall line, you'll see what I'm talking about...

at any rate, i know drifting is different, but I'd still do the same thing on the fronts, and jack up the rear pressure pretty high, so theres more slip...