I just purchased 4 new Michelin Pilot Sport A/S 3's for my 2005 LS430. They are 245-45-18. I noticed I could hear a little whirring noise from 40 mph and up. Long story short, they were repaving an area I drive on every day. As I drove over this, my car became absolutely quiet. But then as I got back to the old pavement, there came that annoying sound. So I got to thinking maybe I could play with my air pressue a little to try and eliminate the tire sound. What air pressure are you running if you have the same tire or what would recommend? I'm thinking about going up a little.

The tires are 245-45-18...my typo

 

It's funny you mentioned the whirring sound. I bought some Premier A/S 245/45/18 tires a few months ago, and I noticed a whirring sound at certain speeds, especially when slowing down. My tires are set to 32 PSI cold. I really miss the Primacy MXV4.

 

Have you played with air pressure to see if you could minimize the whirring?

 

I know on some of the new pavement they lay down, they actually grind up old tires and mix it in with the asphalt as a sound deadener. It makes a huge difference and communities near roads really appreciate how much less noise it makes. It also lasts longer.

 

I don't think pressure will make difference. It's the pattern that dictates the quietness of the tires. Pressure may help, but on what expense.
I start with the recommended PSI then go + or - 2 to 4 PSI. But don't go below 30. Usually I am on the + 2 as its a bit stiffer and this is how I like it.
Currently I am running Sumitomo HTR III 245/45-R18 at 33 PSI.

 

I kept my tires at 34 to 36 PSI and never heard any noise.

 

In my opinion, I have never had a car with a quieter tire than the Primacy. However, the pilot sport a/s has a bigger and more aggressive tread block affecting the road noise. Don't forget that 18s will never be as quiet as 17s either. Correct tire pressures are important but shouldn't affect the road noise unless way out of the proper range.

 

I'm going up from 32 to 36 and see if it makes any difference. As I read some about these tires, some people said after a few thousand miles they really quietened down. We'll see....

 

I have the Pilot a/s it is a pretty quiet tire. Sure do Not miss my Primacy. Pilots if available from now on.

 

Same tire run at 33-34 psi