I'm having a major issue with a vibration coming through the steeling wheel. This issue occurs when I'm accelerating between the speeds of 60 to 80 MPH. I have had improperly balanced wheels in the past so that was the first thing I thought of. What has me confused is that I've had the same issue with my stock 17's (slight vibration), my 20's (moderate vibration, and now my new GS430 wheels. I will mention that the car has the NF (1 to 1.5 inch drop) springs and has been aligned, but I might need to have that checked again. Has anyone had this problem? Or can anyone give me some ideas to what could be causing this?

Could it be lowering? Alignment? Or do all AWD's have this problem?

 

alignment, doubtful. lowering possibly.
no vibration for me even at 145mph, so I don't know. Tire out of balance?

 

I have no idea. I have tried 3 sets of wheels and tires that were laser balanced. Could it be something related to the AWD?

 

You got AWD in CA? Thats a first one I hear I could be mistaken, but I have been following all the "lowering" threads in here and I think remember reading someone (maybe even a few) having a similar problem on East Coast with NF210 when they come to a stop and feel vibrations.

I have AWD and don't have this problem, and don't remember reading it from anybody with AWD with stock springs and wheels. As a matter of fact when I start accelerating, I don't even notice up until I'm at 80 or over.

 

Did you have the problem before the installation of the springs? If so, I'd rule out the springs. If not, where did you buy the NF210 Tein S. Tech Springs? It really sounds like a balancing issue or bad front tire, but it could be the springs if the problem occurred after installation. I know that in the past there was a problem with counterfeit NF210 Tein S. Tech Springs. A very remote possibility, but if you bought the springs from EBay or a third party you might want to read this: http://www.tein.com/counterfeit/warning.html .

Good luck in isolating the problem.

 

I have the same setup and problem. After one year it still happens and I had re-alignments. However, I never re-installed my stocks, so I couldn't say if it were to vibrate with my stocks. I had the car lowered prior to installing the 20's. My vibration started after installing the 20's. I assume that it's because of the wheels/tires. I am having a tough time finding the exact root cause and solution.

 

Are there any other GS300/350 AWD's lowered that are currently experiencing issues in ride quality? Vibrations during acceleration? Are there AWD guys that are lowered with springs with no issues at all? Are there any spring manufacturers that have released an AWD option?

Nardeezy, this is driving me insane! I was thinking that it could be something loose underneath the car stabilizer bar, sway bar, etc. If this continues I'll have to put the stock springs back in.

 

No problems here.

 

I believe a few members, one identified as 4thone who has an AWD with the same springs as us with 18's and another guy named SGT who (last I read) has the same springs as us with 18's as well.

 

sbrown02, what size wheels and tires are you running? With my stock 17 inch wheels/tires the vibration is a very fine that could be mistaken for the AWD drive train.

 

This type of issue is very subjective. My wife thinks the car runs perfectly fine and she drives the car the most. I had to really show her what I was experiencing on the freeway for her to understand, but she still thinks it's okay.

At this point, I have almost accepted the issue. Maybe it's the tires, the iforged wheel outer rim is not concentric with the hub, etc.? The main thing is I was the guinea pig on this forum, I was the first to experience the issues with a lowered and staggered first year model 2006 Lexus GS300 AWD. I may have mentioned it in a few threads but it did not get a lot of responses because not a lot of AWD members were both lowered and staggered with dubs. At least now I know other people have the same issues, which makes me feel comfortable.

The thing that strikes me is that MKIV98TT put his stocks back on and still has the issue. I never experieinced this issue when the car was lowered with stocks.

 

Nardeezy, I mentioned that with the stock 17's I feel a very fine vibration in the steering wheel during acceleration of speeds over 60 MPH. I figure that the larger diameter tires could be absorbing most of the vibration....and with smaller diameter tires there is nothing to absorb the vibration. What's really weird is that the vibration goes away if you let off the gas. So coasting at speeds over 60 there is no vibration. This leads me to believe that it has something to do with the position of the drivetrain. Do you agree?

I really would like to keep these NF springs on my car, but I don’t think I can live with the vibration on my $50k car.

 

We are experiencing the exact same issue and you make a very good point! However, for some reason I have a hard time believing that it's due to just the lowering, although it could be a factor. When I first lowered the car we drove it for about a month until I installed the wheels. I had no issue of vibration what so ever during this period, all of the vibration occurred the moment after the wheels were installed. Immediately after the car was lowered it was aligned. When I initially got the wheels/tires installed, they were balanced and I got them aligned (#2). The first time I drove on the freeway after the wheels were installed I felt the vibration between 60-75mph. Since then, I had the car re-aligned one more time (#3) and had all of the wheels/tires road force balanced except one (another story). As the technician indicated, everything checked out okay, there is no documented proof that the road force analysis passed unlike computerized alignments.

NOTE: Prior to lowering the car it had issues of pulling and the dealer had to re-align it twice, a total of 5 alignments since owning the vehicle.

I think that the road force balancing and alignments may have technician variability. Some technicians may have more expertise and patience when performing a road force balance than others, especially on large staggered wheels with very low profiles. Installing those wheels on a lowered AWD adds more factors for error.

Prior to installing the springs and staggered 20’s I performed as much research as I could to avoid any issues by; talking to different tire technicians, wheels shops, engineers, calling the Lexus technical department, talking to Lexus service technicians, comparing RWD & AWD technical documents and spec’s, talking with Audi guys who roll staggered setups, AWD forums for the Mitsubishi GTO, etc. Throughout all of that research I went with the Tanabe NF210 and staggered 20” wheels with a 0% difference in diameter from front to back. The specifications that Dunlop posted on their website indicated that the front and rear tires I ordered had the same rolling diameter. I am not sure what tolerances are in place but I highly doubt that they are the same in diameter. I can visually see that there is a bit more rubber on the rear wheels versus the front wheels but it may be due to the camber of the rear being more negative than the front, causing it to appear like there’s more rubber. I was successful in one aspect, I did not want the Lexus computer to trigger and problems due to the AFS (lowering), or the AWD system detecting different tire sizes.

The stock tires for my car were Dunlop runflats. On the Dunlop website, the exact stock tire that I have indicates that the rolling diameter is the same as the Dunlops that I purchased for my aftermarket wheels. I totally disagree with this because when I put my 20” wheels/tires next to the stocks, the 20’s were significantly larger in diameter. It might be possible that the tires we are using are too large in diameter and the % diff from front to rear doesn’t help. This is a difficult topic to experiment with because it’s very expensive to obtain samples but I wonder what the ride would be like with 245/30 in the front and 285/25 in the rear. These size tires are very much closer to the stock rolling diameter.

Sorry for the long reply but let me know what you think?

 

nardeezy, I've contacted a couple of my friends....one being a field tech for Lexus and the other being a drivetrain specialist for Hyundai. I'm in the process of working through a few things now. I'll let you know what I come up with. If this idea works we will be able to continue to run the springs with no issues.

 

Any update guys? I just picked up my AWD GS350 and I want this thing to sit lower!

Thanks!