Hi All - I posted a few weeks ago about the sound levels inside my 2006 LS 430. Just a quick background - I am running on 18 inch chromed Lexus wheels and Yokohama tires. There are many wise members on this forum who rightfully explained that the 17 inch wheels would do me much better as well as other tires perhaps. I purchased a proper decibel, meter and I am running about 65 dB generally speaking in the cabin. A newer Mercedes S class supposedly runs at about 50 dB. I test drove a 2023 LS 500 last weekend. The asking price is $83,000 from my Lexus dealer in Tacoma Washington. Although it’s a great car I didn’t feel like it was $83,000 great. My decibel reader measured 60 dB in the 2023 LS model. And I am just as happy to keep my 2006 LS 430. I really like the 18 inch wheels both for their looks and handling. The Yokohama tires really make it perform spectacularly. But of course, I do have to contend with a little more road noise and I suppose a slightly bumpy ride. But most of the time the ride is very smooth although the road noise is may be a bit louder than I would like it to be. I decided that the handling and looks characteristics are too good to give up, and I would like to try to find other ways to dampen sound. I considered, putting in some sound deadening material in the doors or the trunk or the fender wells. I watched some videos where the doors are removed and it doesn’t appear that there’s any room to put any sound deadening material inside. It looks like Lexus did a pretty good job doing that already. In the opinions of the members on this forum, who are much smarter than I am, do you have any suggestions on where I might put sound deadening material? Or is it even worth bothering? Maybe I should just live with it. In the scheme of things I guess it’s really not that bad. It is still the most comfortable car I have ever owned or driven. I am just always looking for perfection or making something just a little bit better. Open to your wisdom fellow LS owners.

Victor

 

On the LS 430 and 460, the front wheel wells aren’t lined in felt like the newer models are which help quiet tire noise. Also if your LS 430 isn’t a UL or CL model, you most likely don’t have the double laminated door glass which makes a huge difference in quieting outside noise.

One way to help dampen the road noise up front which I did on my LS 460, is to buy some stick on sound deadening foam padding on the plastic wheel. This helped cut down on road noise on the car tremendously.

I actually did a combination of the thick foam padding and the stick on rubberized sound deadening pads.

Switch out those Yokohamas and get some Continental ProContact tires, those are very quiet tires and absorb road shock well.

Moving up to a fatter tire with larger sidewalls will definitely help with bumps better, but you’re going to have to source some wheels from a pre facelift LS 430.

This is why I hate modern cars at times because tire sizes keep shrinking, while wheel sizes keep growing which always makes the ride of a vehicle very rough especially if you live in a place where your infrastructure is falling apart and you have to drive in horrendous streets and freeways with broken pavement and potholes left and right. I’ve seen so many cars locally with blown out tires and bent rims because of the potholes are destroying peoples cars around where I live, it's terrible.

The previous owner of my 05 LS 430 installed some 18 inch aftermarket Lexus wheels, and the tire size is a horrid 45 series, which is way too thin of a tire on a luxury sedan IMO because it allows too much road noise and harsh road impacts to enter the cabin.

I found some nicely used chromed 17 inchers from a 2003 LS 430 that I plan on installing some time soon. Those tires are a 55 series, which is a lot more sidewall which will help with ride quality and smoothness. IMO a 55 series tire is still too short of a sidewall, but it’s still better than 45 or 50 series by far, as a 60 series is even better at absorbing potholes and very rough roads.

 

My 2004 LS430 is considerably quieter than any other cars I have owned, including two Acura RLs (1998) and a 2001 S320CDI. Mine has the factory 18" wheels with 245/45-R18 size tyres.
Before buying it I test drove a couple of pre-facelift models on 17" wheels and a few LS400s on 16" & 17" rims, and none of them were as quiet as the facelift models.

The fatter sidewalls make the ride more compliant and reduce damage from crappy roads, but they don't really have any effect on tyre noise.
You will get more of a reduction by shopping for quieter tyres or else fitting sound deadening to the inner wheel wells as stated above.
I am going to try the Pirelli P-Zero PZ4 next as they have a good reputation for being quiet but still having good grip and wear.

 

Thank you sir! I appreciate the feedback very much. I believe I'm running on the ML version of the LS430. Wondering if it's possible to replace the windows with double-laminated door glass. I suppose just finding them would be a challenge let alone installing them if it's even possible. I think I'll take your suggestion and start with the wheel wells which was on my list of sound dampening. My main concern was the amount of space between the fender and the plastic wheel-well guard. Did you have any trouble replacing the plastic guards after you insulated them? My Yokohamas are only a month old so I'm probably not going to replace them now but I will certainly consider the Continentals the next time around. Continentals were on my shortlist of tires but another LS430 owner recommended the Yokohamas. I have to admit that they really handle well in spite of some extra road noise. Presumably they are supposed to be tuned to eliminate noise but I'm not so sure. However yesterday I had them up to 70 mph and they actually were 2 Db quieter than at 60 mph so who knows. I've watched Youtube videos of guys literally stripping the interior of their cars right down to the floor boards and installing Butyl backed aluminum sound deadening material. Of course they were not LS model cars and probably didn't have much noise insulation to begin with. I don't have the guts to remove the interior of my car. I can already imagine the nightmare of things not fitting back together right and ending up with creaks that I didn't have before. And then of course being left with extra nuts and bolts that I missed. No thanks! I am wondering however about the trunk area. When tapping around the car I notice the rear quarter panels sound very hollow and tinny and not as solid as other parts ot the car. It looks like it would be fairly easy to remove the trunk liner and that's something I think I'd be comfortable taking on. Sound deadening the trunk may not be that hard and there does seem to be plenty of room to apply the materials. The question is - would sound deadening the trunk have any impact in the cabin. I sort of have my doubts but I'd be curious to hear the opinions of others. Thanks again!

Victor

 

Thank you for your reply BigBoomer. I'd be very curious to hear how the Pirelli's perform verse what tires that your currently running on. What tires do you have now? These tires were also on my short list of tires. I do plan to insulate or sound deaden the wheel wells. I'll report the Db change after it's completed.

Victor

 

Currently have Goodyear Eagle F1 Asymmetric 3.
They are moderately noisy and were from new, but grip and handle well.
However, they have only 15k miles on and are at 4mm tread depth so the wear is poor.
I am not impressed with the mileage.

My previous tyres were Avon ZZ5 and they lasted 30k miles, were comfy, grippy and quiet.
I would have bought them again if they hadn't been discontinued.

The choice this time is between the PZ4s and the Primacy 3 or 4 but I am leaning to the PZ4 due to reports of how quiet it is.

 

I spent weeks trying to decide what tires to buy. I was about ready to pull my hair out reading reviews. It seemed as if every tire had good reviews and bad reviews. I would read 5 reviews about a tire that raved how good they were and then one bad one saying it was the worst tire they ever had. It certainly made it a difficult chore trying to decide. As much as I like the way the Yokohamas handle, I believe that you're right and that there is a quieter tire out there. After only having the Yokohamas for a month now I don't think I'll be shopping for new tires anytime soon. Therefore sound deadening is my next pursuit. I actually considered buying a set of 17" rims to keep on hand and put some quiet tires on them. I was thinking that maybe I'd use the 17" rims for winter driving and the 18" rims for Summer driving. It was just a thought. I was seriously considering upgrading to a newer LS500 but after a test drive couldn't justify the cost. I love my LS430 and not ready to give her up. The engineering and build quality is some of the best.

 

It would be best just to find another LS 430 in CL UL trims than trying to find double laminated door glass off a donor car. I can’t imagine the expense having to replace all four door glasses.

Here are some photos of the products I used on the plastic wheel liner for my 460. The process is the same on the 430. You just want to make sure that you have enough space so the tires don’t rub on the material.

I first laid down the rubber pads, and then the closed cell foam padding on top of it. So far it’s been over a year and the pads haven’t come off or peeled away. The foam pads are pretty thick so again, make sure you have enough space. You could definitely do the trunk and or the inner quarter panels to make for a more solid feel. The foam pads helps more for sound absorption vs cutting down on vibration. But both work best for cutting down on noise altogether.

 

Thanks FnL. The pics are great! I noticed that you applied sound deadening foam and material to the outside of the wheel well. I've seen video's where they applied on the inside of the plastic wheel well guard. It wasn't an LS model but one guy put it on the inside of the wheel guard and on the inside wheel well. Doesn't seem like there would be much space in there but I've never removed the guard so really not sure. I don't think they were using the foam but rather butyl and aluminum sheets like Dynamat. Would you say that your application of the materials made a noticeable and significant difference to improve road noise levels? Also curious why you picked Siless? There are so many products out there that it's a little overwhelming knowing which one to go with. I'm not worried about cost so much and really looking for something that will work well.

 

I watched a few Youtube about how people tried to add sound deadening material in the wheel well. The results aren't that impressive. It added cost and weight to the car. Again, those are just the opinions from those guys who posted.
Chasing quietness seems little too much for an older car. If I drive my older Civic for a couple days, then my LS becomes super quiet

Oh, btw, I also checked out the newer LS at the dealer the other day. They have both LS and ES parked inside. Man, the ES uses the "same" steering wheel/odometer, look alike dash, front end but near half the price as the LS. So wrong...

 

I think that's one of my biggest concerns Intermec. Spending time and money on something that doesn't do much except weigh down the car doesn't sound like such a great idea. However there are those that report that it made a big difference so I guess it just depends. I wouldn't say that my LS is overly loud but maybe a little louder than I think it should be. It does seem to be emanating from the tires and otherwise the car drives as smooth as silk. I just love the 18" chrome wheels and just bought new Yokohamas that handle amazingly. So I guess that's the price you pay for performance. Nevertheless I'm still searching for a way to keep my current wheel/tire configuration and knock off 5 Db in the cabin. Pretty amazing about the similarities between the LS and ES. I just test drove a 2023 LS 500 at the dealership in Fife and although it's a very nice car, I'm not sure it's $83K great - Lexus' asking price. Of course my 2006 LS 430 doesn't have massaging seats, HUD, or the 2400 watt 23 speaker sound system or air suspension but there are a lot of bells and whistles that probably cost a lot to repair and maintain that I don't have to worry about either. I'm very happy to stick with my LS 430 which was engineered to go 1,000,000 miles. Just want to find a way to make it even better!

 

Yes the difference was definitely noticeable. It muted the road noise much more compared to before. Out here in California most of the freeways where I live are concrete which is loud to drive on, I instantly noticed a difference driving on the coarse pavement prior
to adding the material.

I think closed cell foam padding really helped more
so with dampening the sound waves than say the butyl rubber pads. I think adding the material to the plastic wheel well works better because the tires also flick rocks and debris which I could hear before sometimes while driving and now it’s literally non existent.

if you’re worried about added weight, you can possibly skip the rubber pads and just add the foam pads which are feather weight light.

Adding more mass to a car IMO gives an added sense of quality. Very heavy cars like RR’s ride extremely smooth because of that added weight density helps the car absorb road impacts and vibrations.

Of course suspension setup and tuning also matters a lot, but every lightweight car I have ever driven are all usually very loud and ride harsh.

A quick example I’ll give you is that many years ago I used to own a 98 Honda Accord coupe. The doors on those cars were very light. I decided to add some sound deadening pads to the inner door panel on the drivers door since something was wrong with the window so while the door panel was off of the car, I added a few sheets of butyl rubber pads. The effect of the rubber pads was highly noticeable.

The door closed with a much more solid “thunk” vs a “clank”. It was heavier feeling, but a nice quality heavy feeling as the doors closed with nice feel. Compared to the passenger door, it honestly felt like a different car door altogether.

So it’s up to you on how far you want to take this, but it’s worth a shot trying. I chose the Siless brand because it has great reviews on Amazon and the price was reasonable and not ridiculously expensive like say Dynamat which is essentially the same thing as the Siless brand.

 

Great info - Thank you FnL. I very much agree with you that some added weight also adds the sense of quality. I have no issues adding weight if it improves ride quality. I think I'm ready to go down this path. Just hope I don't end up down a rabbit hole - Lol.

Thank your sir

 

No problem, glad to help. Keep us updated on what you decide to do and what the outcomes are.

 

I have been giving it some serious consideration on sound deadening and decided to invest in some what I think are pre-facelift wheels. They brand new Lexus chromed OEM 17" wheels. Toyota stamped on the back. I plan to put on some Michelin Primacy 3 tires and this will be my first step towards sound deadening. I love my 18" chrome Lexus wheels with the Yokohamas and I plan to keep them. I started thinking that wheels and tires are kind of like shoes. You wear shoes for different reasons and different occasions. I might use the 17" wheels for Spring and Summer and the 18" wheels for Fall and Winter. Or would put on the 17" wheels for a road trip but the 18" if I wanted to do a little more spirited driving. I guess the idea is that I would have options. Next plan is to insulate and sound trap the wheel wells, all four doors, trunk and I might even attack the floor pan. But I'll do this in stages. I also plan to upgrade the existing sound system with new speakers and maybe an amp and a module that will allow me to play music via bluetooth. I currently have a bluetooth adapter that I can plug into my tape deck but I don't think the sound is all that great.