Just aquired a beautiful 2004 LS 430 with 67K miles - beautiful car...except it rides like a truck!
My LS 400 is cream compared to this 430. Every bump rattles the car and road expansion joints seem to risk suspension damage. OK, reading all the posts - it's the tires or the struts (no air).
The Dunlap S-4000 tires are good - but even at one or two lbs below the 32 lb level, it's no help.
And, on concrete the noise is high whatever the pressure (that's the tires). So, the KYB struts - Lexus inspected it before my purchase and did not report strut seal leaks. They said replace the tires. I don't want tt drop $800 or so on MXV4s and find out I then have to replace the struts too.
Also, there's the seats - beautifully crafted and adjustable every possible way - and rock hard!
The LS 400 seats have a nice supporting softness to them but the 430's are...well, hard and not all that comfortable.
I can't change the seats - and if it means thousands fixing the tires and the struts - I may just sell the 430 and give up all the other wonderful things about it.
Will brand new tires change the ride to the smoothness thqt the LS is noted for?

 

i bet its the tires?

 

I had the same tires as you and I replace them with Michelin mxv4 tires and the ride was 100 percent better.
I am testing the new Nitto Movito tires. I let everyone know how these tires work out.

 

I currently have both an LS400 and an LS430. I am very happy with my LS430 but it is primarily due to the gadgets such as laser cruise control. I agree that the LS400 rides softer but it also doesn't handle as well. Also note that the recommended air pressure in the 430 is higher which adds to a harsher ride. i'm fortunate that my 430 has the uncooI 17 inch wheels so at least my ride is better than many LS430's which have lower profile tires.
I also agree that the seats are more comfortable in the LS400. Also, the cooled seats don't work well and may actually be part of the problem with the seats not being as comfortable in the 430.
My LS400 has quite a bit more wind noise but that is primarily due to my being too cheap to put out $500 for door seals on an old car.
The 430 has quite a bit more power with a great transmission so that is good.
Unfortunately the 460 has moved significantly further from the 400 so we'll never see an updated LS400. That would be a car.

I had the Dunlops and replaced them with Michelin Primacy and that made a significant improvement..

 

Just broke the LS430 out for the first time in 5 months (on summer break)! I must say, after getting used the winter car (a 2008 5 series), I noticed that the LS was much quieter and rode quite a bit smoother (really insulates you from the outside). Seats were also really plush compared the 5. I guess it's all relative.

If you're unhappy about the road noise, try swapping out the tires for those primacys. Shocks are not going to increase road noise. A softer tire will also make the ride smoother. I'm also currently on the stock Dunlops. I think they're adequate, but not great. I can only imagine what the primacy's will do!

 

Auto upholstery/reestoration shop for the seats, new Primacies or comfortred touring for tires.
If you new it needed new tires and then bought the car when you did not like the ride why are you waiting to get new tires and just bite the bullet?

My car is fantastic, but I drove a 04 with Kumho tires and it was loud, handles poorly with a poor ride. I gave the keys back to the dealer and thanked him and left.

It prolly can't be the struts especially if it has not been a city cruiser. A motto for cars I use "when in dought do without"

 

I have winter tires and wheels...17" Hankook H727...that I switch to from 18" Dunlops Even with low air pressure, they make a very small difference in ride quality compared to the 18" Dunlops. I think you either learn to appreciate the firmer suspension control and better responsiveness of the LS430, or you need to switch to a different car.

The firmer ride put me off at first too, but you get used to it. This is still an extremely low NVH car, with a very steady ride. It's hard to beat the super smooth transmission and immediate acceleration. The reliability reputation is worth a lot too. So, I say keep the car and appreciate all it has to offer, including the more nimble handling from a more controlled suspension.

 

Most luxury cars these days have firm rides. It's not like the old days when a Caddy would float over the roads giving you that feeling of floating over everything. That's unfortunately the not really the deal anymore. As luxury sedans go, the LS is the softest IMO.

Compare the 7 or the A8 to the LS and you will find even firmer suspensions and tires with even lower AR than lexus uses.

Changing tires will improve the noise issues and "roll smoother" but it won't be a dramatic suspension firmness change. If you want that, go get yourself a 1970's luxury GM barge like a Buick LeSabre or a Lincoln Town Car (77 is my favorite...so huge..)

 

Why did you buy a car that "rides like a truck"? Just wondering.

 

People in my car use the word smooth, I prefer huvmobile its made to absorb the rode not tame it. A8 535xi I drove push your speed into the turns. After 30-35 this car susp gets scarey/spongy in turns not inspiring. It has many more good qualities than bad and does not break.

 

Tires can make a huge difference. I have 17 inch wheels and running Primacy - ride is smooth and handling very good given the reality that the 430 is a land yacht .

 

Sounds like air suspension issues to me. When mine sits for a few days it rides poorly for a few miles while the air sorts itself out. If the car has air I'd look there first.

 

How about checking the motor & tranny mounts?

I had similar issue, which was resolved with
mount replacement.

 

How about having a Lexus dealer look at the car and get their opinion as to what is wrong?

 

What does NVH mean? Where can I find what these abbreviations mean?