I recently purchased new tires and had an alignment performed on my 2006 GS300 and am noticing a few symptoms:

1) Steering wheel vibration (jitters slightly to the left and right while driving straight)
2) Wheels/tires making an intermittent hollow-ish noise with each wheel rotation (not quite sure how to describe the sound)
3) Feeling of lessened control over concrete pavement going 40+MPH (car seems to track to the left and right as if I'm moving the steering while going straight)

My initial set of tires I've swapped out were Falken RE912s, which were great tires, but had uneven wear on the outer edges. I went with the BFGoodrich g-force Super Sport A/S as replacements, which were much louder and did not handle as well. I had the alignment perfomed the same day the tires were installed. The shop said they put all of the specs to factory, except the offset because Lexus does not specify the info for this vehicle.

I noticed the symptoms noted above. The tire shop rebalanced my tire, noting that the balance was more than 1+ off from when I installed them just a week prior. I drove around for another week and still had the same symptoms. I brought it back noting the same symptoms and this time the shop swapped out the tires completely for Michelin Pilot Sport A/S Plus tires. They mentioned that certain cars do not perform well with the BFGoodrichs, such as Lexuses, BMWs, and Mercedes. The Michelins are a lot quieter and feel a lot sturdier, however, I'm still noticing the same symptoms above.

I'm pretty convinced that the tires are not the issue and am planning to bring the car back to the alignment shop later this week to have that redone.

Has anyone experienced a similar situation or any advice on what may be causing the symptoms?

Also, would anyone happen to have the alignment specifications for this vehicle? I've read somewhere that shops may sometimes incorrectly align the 2006 gs300 with the 1998-2005 gs300 specs.

 

Regarding your steering vibration, 99% chance its your tires out of balance. Are you on factory wheels? If not, are the wheels you're running hub-centric? If not, that's your issue. Just remember that when tires are balanced to a wheel, they are balanced by the center bore. If your wheel is not hub-centric (center bore is the exact same size as the hub of your wheel), then you are not mounting the wheel on the hub, rather by the lug nuts. You could have hub rings that typically help.

#2 and #3 sound like tire issues to me.

 

I have the same tires and I don't have any of your problems.

 

Yeah, I'm on the 17" factory wheels. They've re-balanced the tires 3 times and also remounted a new set of tires, so I'm starting to think it's not the tires. Hopefully the re-alignment will do the trick... I'm still kind of weary about the specs they're using for the alignment.

 

When I got my '06 GS300 w/the Dunlop RunFlats & 5-spoke 18" factory wheels pulled from a new GS430 as part of the deal, within 1 week I started experiencing drifting & disconnected steering wheel where the car felt as if it was floating. I had to constantly make corrections with the steering wheel to keep the car in my lane. I went thru 4 wheel alignments (3 by dealer & 1 by a local Goodyear) within the 1st year of ownership. At one year, during safety inspections (Virgina requirement) the tech noticed I had unever wear on my tires (which had just been rotated the day before). Long story short, I went back to the dealer w/the complaint & Lexus Corp had them test suspension parts, alignment, & etc. They concluded I was sold a bad set of runflats, & they gave me a new set in June '07. I have not had the problem since & miraculously my alignment has been fine since them.

I concluded that when the tires & wheels were on the GS430, they sat at the dock or the dealers lot since fall '05 when they began shipping the cars to the USA, resulting in what are called "dead spots" which can develop on runflat tires if the car sits for extended period of time.

 

Alignment has nothing to do with the vibration you are getting. Goodrich tires are mainly junk compared to high end tires like Michelins and will have more pain in getting them balanced. I would not trust that brand as I have had experiences with those in the past. Pure crap tires. Now, I recommend that you pay more money and go to your Lexus dealership and get them ROAD forced balanced. Not a simple dynamic balancing. Road Force balancing Hunter machines will detect bad tires or bad rims and help mount the tire on a better position on the rims. Those Michelin Pilot Sports however caused my car to vibrate badly despite road forced balancing and 1 lexus dealership told me that the agressive tread patterns on the Pilot Sport can cause some vibes on highways and grooved roads. Thats why I got rid of them last year and got the Michelin Primacy for my 18 inch rims. Look at those Michelin Exaltos for the 17 inch rims. Those are perfect.