grabber2

Driven my new ride for 2 days, here's my feedback:

My sc430 generate loud tire noise even under 30mph, so loud that it cover wind noise above 60mph+, increasing vibrations on steering wheel at 50mph & above , rougher ride on average NYC road that My 05 G35x. & TPMS light was on all the time even my tire are at 32~33PSI

Was it because of the RunFlat Summer tire??? I mean its so rough & loud that I thought my spring/shock is failing. (maybe its failing with 82K miles??)
My sc430 comes with 245/40R18 Dunlop SP Sport 01 DSST RunFlat (Ultra High Performance Summer). Link to Tire on tire-rack.

Does anyone here use the same tire & have issue with it??? or my suspension is due for replacement?? I really think the SC's ride should be much more smoother. I initially plan on getting a set of 19" MRR GT1 Link with 255/35R19 Ultra High Performance all season (non-runflat). Now I will have to rethink if I should get 18" & touring tires due to the rough ride & tire noise.

Poqman

I bought my '02 with 84k miles. Immediately realized I had to get rid of the run flats. Bought new wheels and Bridgestone Potenza's. Stayed with 18" wheels to try and keep the best ride and allow me to do 4 wheel rotations of the tires. Definitely request the tires be road forced balanced when they are mounted. This solves the high speed vibration problem typical felt on these cars. (FYI, Can't recommend the Potenza's due to flat spots when the temperature drops below 55F. For the first 3 miles every morning in winter, it feels like Fred Flintstone tires.) These solved the ride harshness and noise, but did not solve suspension problems at high speed. Some interstate road conditions made the car feel like the suspension was unstable. Had the car inspected by Lexus, who reported all suspension parts were okay. Drove for a year assuming this was the best the car could do. Several weeks ago, I replaced the OEM coilovers with Megan EZ coilovers. Problem solved! Now with 96k miles, the car drives and rides great. If you have 82k miles, I highly recommend you change the coilovers and swap out the RF's..

grabber2

Yes, I looked into the mega coilovers but not sure if it will make the car feel stiff or smoother. I don't want to lose the comfort on the SC. I have the runflat summer tire now but outside temperature is 25F~35F.

mandyfig

The issue I think is the set of tires. I have the same HUM noise that is irritatiing on speeds below 40 MPH. Once you start reaching 65+, quiet as a bird. But there has to be a good set of quiet tires. Unfortunately I have a brand new set when I bought the car, no name brand though.

Poqman

Definitely smoother. Provides a very comfy ride.

scdroptop

iTrader: (1)

Huge fan of the Megan coilovers! Just had mine done a few weeks ago and love them! I actually think it feels more like a IS250/350 and G37 (I get one for a loaner every other month or so for my FX35 when it's in the shop) now with the coilovers. I don't have an aggressive drop and it's not on the stiffest

Do your MRR GT wheels and stagger them, put nitrogen in the tires, then do the Megans. After all said and done, get an alignment and it should be smooth!!!

TooCoolSC

There have been several people report that coilovers made a big difference in the driving experience of the SC 430. So if the suspension and ride seem to be a problem and/or complaint, coilovers are likely the best solution.

But if you aren't ready to spend the money on them, some here have noticed a definite improvement by replacing the lower control arms.

Getting rid of the runflats are also supposed to make a big difference, but I've always wondered how a car would drive WITH runflats AND coilovers, or WITH runflats AND new control arms. In other words, are the runflats really the problem of the bad ride?

It seems everyone always starts trying to improve the ride by getting rid of the runflats first, and doing suspension related tasks (coilovers/control arms) after that. But what if you were to START with the coilovers?

Anyone here have coilovers AND runflats? It would be interesting to know how that combination works.

The main reason I don't like the runflats, though, is their expense for the limited mileage you get on them. Regardless of the ride, I don't want to have to spend big bucks every 15,000 miles or so.

grabber2

Thanks guys. Will definitely get the 19" MRR GT1, stagger or not......most likely 19x9.5" all around. As far as coilovers, I never try non-stock suspension due to reiliability issue & stiff ride. Unless I decided to drop, I will keep it stock if nothing wrong with them. Btw.....I have to put my wife's concern on the ride comfort as the SC is technically her car.

I just realize I have a set of spare Michelin pilot All-season 235/45R18 that I gave to my friend's 2004 LS430. He's using the snow-tire now. I will swap them for the winter to see a different vs OEM run flat.

Harold57

It is common for some of the tire treads to get "cupped". Once they do that, they do get noisy. My last two sets of RFs did that. They started out quiet and got real noisy. The first time I heard it I thought that I had wheel bearings going out because that is what they sounded like. So most likely it is your tire wear creating the den.

Proper alignment and puctual rotation will keep that from happening as much or as soon. Once it happens, there isn't much you can do short of replacing the tires, having a tire shop machine them flat again (shortens tire longevity) or just bear with it, maybe using some earplugs...
Harold

mandyfig

Sounds like I need an alignment. At least to not damage the tires. But my tires are new but they make the humming noise, perhaps they are el cheapo, no name brand?

Harold57

Some tires are just noisy from the get go.

mandyfig

As mentioned above, this sounds like a bearing failure hum...I need to get it on a lift and find out. Will check the front wheels on free play.

scdroptop

iTrader: (1)

Aren't our stock tires 245/45/18? At that size they will be stretched more to meet the wheel width, therefore be lower/shorter in stance and may perhaps be a rougher ride than the stock size. You may want to go with lower air to compensate just for comparision purposes.

Trust in the CL brother/sisterhood...the non RFT's are 200-300% better!!

grabber2

Thanks guy,

Friend use the Michelin 235/45R18 on his LS430 stock rim (OEM tire 245/40R18) and have no problem. I drive it and it was great. It's Performance touring so it's comfort and quiet.
It will definite better without the RF summer tire. I will use the Michelin for winter and get the MRR GT1 on Spring 2011. so hard to decide If i should get them in hypersliver or chrome..

Thank you guys for all the help......I love the color of the PB SC, especially the interior & the MARK LEVENSON

Pnuge88

iTrader: (1)

those run flats are RIDICULOUSLY LOUD! and my car doesn't grip for nothing!!

you won't be disappointed in upgrading with coilovers. if your not planning to drop it. the coilovers will still enhance your handling. the stock suspension feels too "loose" the dampening is also adjustable so you can get a ride close to stock or even the same if you keep the height in stock specs