I am getting my RFs replaced today with the Sport Pilot. Any suggestions on the tire pressure? I have been using 39 on the Dunlop RFs.

Just hope the new ride is all people say it is. Presently rides like a Jeep. My Dunlops are actually falling apart at the seams after 25k of light driving on good roads.

 

I just had my RFs replaced with the Pilot Sport tires and, so far so good. I am now aiming for potholes. Not quite, but close. What pressure should we use in these? I know 39 was recommended for the RFs to "smooth" them down. Oh, no more tramming that I can tel. That was one of my biggest complaints, other than loose fillings.

 

I have the pilot sport ps2 and keep them at 40psi. I think most people keep them at around 36 to 38. I keep the extra pressure to help protect the rims from potholes

 

Well finally I di replace my RF tires with michelin Pilot Sport PS2. There is ahuge difference as everybody else says. I hope to sell the RF tires on ebay. I hope I can find some takers.
I have one more question. What is the proper pressure for the tires in this car? The manual says it should be on the side of the Driver side door. However, in my car there is no such information on either side doors. Can someone look at the info in their car and tell me what should be the proper pressure of the tires. For reference I have a 2003 SC 430.

Thanks

fatih

 

Fatih, Lexus recommends 32lbs. Depending on where you live you might want to carry more, because of temperture flux. I run 38 psi at 70 degrees, since you lose 1 psi for ever 10 degrees of flux. So I am good to go for down to 10- 20 degrees. The tires feel the same from 32 psi to 38 psi and the higher pressure protects the wheel rims since the lower your pressure the potential increases for rim damage with our low aspect ratio stock tires.

 

rule of thumb, ALWAYS ALWAYS measure tire pressure when COLD, nothing else. measure it after you wake up in the morning and the car has not been driven at all (in the garage). that's the only accurate measurement. anything else is not. the ambient temperature outside has absolutely nothing to do with the temperature inside the tire, which is the important factors. depends on your driving habit, road surface temperatures, etc... the temperature inside the tire could vary a lot

that's why, ONLY do it when cold.

with that side, on 18s? usually i recommend about 35psi cold. 38psi the most imho

 

Anyone use nitrogen fill? What are the benefits? Downside?

 

Benefits:
Larger molecules don't work their way out of the tire as easily. (Tire will not lose air as quickly)
Nitrogen is inert (less water, etc.) so it isn't as susceptible to pressure change with temperature.

Downside:
Cost? (Expensive for the shops, but negligible for the customer.)

PS: Can't wait for the tires to wear out on the SC.

 

Wrong; it absolutely does. What temperature do you think the air inside your tires is? It's the same temperature as the outside. And after car is driven, it'd be 'x' degrees hotter than the outside temperature. Outside temperature is always going to be a factor. And yes, tire manufacturers take into account the tire's air being heated much higher than ambient temperature; that's why is so important to check air pressure when COLD indeed (just like you said).

Now, if you check your tire pressure in your garage at 80º, and you park it outside at 60º, when the temperature equalizes (change is not immediate, just like when hot food starts getting cold), air inside the tires will also be at 60º, and 2 psi lower in pressure.
By the same token, if you start driving right away under the above scenario, you'd be fine then, but still be 2 psi lower the day after.

When temperatures start to plummet, is more important to check air pressure more often. Inversely, you hardly have to add air from winter to summer, because rising temperatures usually offset normal air leakage, and pressure seems not to fluctuate at all for a long time. Good day.

 

true, i agree with you. i guess what i was trying to say is that you don't drive to the gas station and put in air when reading from the car that it's 70 degrees outside.