At what tire size does the great Lexus ride quality start to fail? I want to upgrade my stock rims to 18's or 19's but I really don't want to feel the road too much. Thanks

 

You will notice a decline in ride with the 18's. A friend of mine has the standard rim I think you probably have. She has a 2001 LS which rides much better than my 2006 LS Ultra with the standard 18 rims. Less tire wall means less of a smooth ride.

 

Going to a larger wheel while maintaining overall diameter of the wheel/tire, you are basically substituting 1 inch of compliant rubber sidewall on the tire for 1 inch of non compliant aluminum - ride has to suffer with every incremental increase in wheel diameter.

 

Ride is important to me but these stock rims are gross. I'll try looking for a good looking set of 17's and see what I come up with. If anyone knows of any, please post a link. Thanks for the help.

 

Yeah there is just no way around it, all else being equal less sidewall = harsher ride. Also the lighter the tire/rim package (less unspung weight) the better. You have to find your own sweet spot of looks/handling/comfort, no one can do that for you.

 

Do you have an Ultra Luxury?
I had an 01, sport package with 22" lexanis on lexani 235/30/22s tires. I was surprised with how much my ride quality was not changed. also every time someone brought up that the tires would make the car ride like crap i would invite them for a ride and change their minds.
i will tell you that my 06 ls430 modern luxury, sport suspension is slightly softer than my 01 was. but i will also comment that ***** I FEEL***** that the factory air suspension on my 04 UL ride quality is not as comfortable as the factory springs on my 06.
i currently own the 04 UL and the 06 ML so i have done the comparisons.
If you know someone who will let you try on wheels, do it you may be surprised at how it rides.
lexus has put a lot of time in designing the spring rates of these cars.