ScBouncE

So the factory tires are said to be driven on 32lbs of pressure. Just wondering if riding on more pressure would affect the ride quality of my car as well maybe increase fuel economy? What do you guys ride on?

Luxor

iTrader: (15)

I have always filled up my tires 5psi lower than the maximum pressure. I would assume that more pressure would give you better gas mileage, but will hinder your ride quality.

iwannadie

iTrader: (1)

I just checked the ole ladies sc300 tires and topped them all off at 32psi. I always figure if I am running factory rims and tire sizes that factory PSI spec is best for me.

STRTORPTR

Same here.

"Keep a Lexus running like a Lexus should" I always say...

good2go

iTrader: (6)

Hmmm, to be honest this just sounds like a pretty bad idea. Ride QUALITY is not defined simply by softness. Sure, this will give you a softer and more plush ride quality on the cheap, but in an emergency situation, it could mean the difference between having a catastrophe or not. IMHO, if you are seeking that soft and plush of a ride on a long term basis, then you would be better off tweaking your suspension to that end while still maintaining a fully functioning (responsive) tire pressure.

While I'm constantly seeing people on the road with underinflated tires, I just always thought they were negligent operators, but your post makes me wonder if that many people do actually sacrifice their car's emergency handling capability in the interest of a free soft ride.



EDIT: I'm assuming you meant 5 lbs. lower than the inflation number given by Lexus for your vehicle with stock tire size, and not the true MAX tire pressure stated on the side of the tire. Those are completely different specs, although I'm pretty sure that 5 psi lower than the tire's true max is still not anywhere near optimal pressure either.

MidloSC

iTrader: (1)

I think he meant the mas PSI on the tire. ie: If the max rating on the tire is 55psi, he will inflate them to 50psi. At least that is how I read it.

good2go

iTrader: (6)

That doesn't make sense though, as the car would ride like a rock.

QwkSC

iTrader: (1)

OK, I am going to say 2 things first:
1. I work at Discount Tire
2. My family owns a buisness, where we test tires.

You should always inflate your tires to the manufacturers recommended pressure. This is important for several reasons
-Underinflation will wear the outsides of the tire faster, while killing your gas mileage.
-Overinflation will wear the center faster than normal and can give you a harsher ride.

There are a few times you may want to run lower or higher than normal.
-Inflating your tires OVER the recommended pressure can give you better gas mileage and help if your vehicle is heavier than usual(like while towing something)
-Inflating UNDER the recommended tire pressure can be useful if you need more traction (like on a 1/4 mile run)

If you are running stretched tires, you may want to inflate over the recommended tire pressure(pure guess, say 40PSI) since the shoulders are getting used more, overinflation may help even out tire wear(Disclaimer: It is NEVER recommended to run stretched tires)

4thHorsemn

38psi here! I need to put some nitro fill in!

Luxor

iTrader: (15)

Yes, you are correct. My maximum pressure on my tires say 51psi. I inflate them to 45-46psi.

vietunit

iTrader: (5)

34 psi on my stocks

RedPhoenix

iTrader: (10)

37-40psi...

VinnyMac

iTrader: (1)

I run them at 35psi..

After reading qwkSC's post over stretched tires...I might try 38psi to see if the wear evens out a bit

iwannadie

iTrader: (1)

I always am surprised by the people that read the tire sidewall and inflate to that PSI thinking that is the correct PSI and not the Maximum.

If you inflate to the maximum and go beyond the maximum weight rating for the tire you are in for some trouble fast. Even at the max tire PSI and hitting a harsh pothole can end badly I'd imagine.

I can't remember where I heard it(one of those car tv shows) but they made a compelling argument for not Under inflating street tires at the track. They explained the tires are designed to get the most grip when properly inflated. Under inflating and deforming the tires doesn't gain grip as it would on a drag tire that is designed around low inflation. I'm sure it's going to be one of those things that everyone has their own opinion and proof to back it up though.

QwkSC

iTrader: (1)

Yes that's true, but Competition Tires (like drag radials) are designed to be run low(like 22psi). You really should play around with tire pressures to find out what gives you the best times even if you have regular street tires. For instance, I usually inflated my fronts to the max(least amount of drag) and the rears I ran at 30 to get the best times.