ibidu1

iTrader: (1)

Just because all your tires are cupping doesnt mean its from bad camber. Post a pic of your tires and we can see what is going on

isfdude

iTrader: (11)

Sometimes a bad toe adjustment will also cause cupping.

350AWD

What fellow Lexus members are saying is true. Cupping can be caused by few things, bad shocks, toe, etc. Google search tire cupping you will find few good videos that will give you an understanding on what's going on.
How many miles on the car?

In my case, first I had rear inner tire wear caused by camber I installed SPC bars but had cupping. I decided to take one shock out and tested it. Shocks were bad at 51k miles.

When was last time you did an alignment? How often you rotate tires? You have AWD or RWD? If you give us more details on what's going on I am sure someone here will guide on the right track

energie8

I stored the summers which has the issue, I'll post them once spring kicks in when I take it out of storage.

energie8

I have 300k KM, twice a year alignment/rotate, all stock on 18 inch, AWD.

cschroder

I've had lexus gs's for 2 generations of the car now to the tune of 300,000 miles. Tire cupping has been an issue on both, especially if you are a "spirited driver". When tire cupping becomes an issue the first place i always look is the lower control arm bushings, front and rear. To properly inspect them, you have to remove them, put them in a vice, insert and punch or screwdriver into the metal internal ring and pull and push. If it moves more than just a little little bit, replace it. These cars are heavy, fast, and have good brakes. When you mash on the brakes, if there is any toe in at all, which there is from the factory for better handling, it is greatly exaggerated by even slightly worn bushings in the lower control arm, add the camber to that and you have crazy stupid inside tire wear with cupping.

I put lots and lots of miles on my cars, my rule of thumb with these lexus gs cars is that every 100,000 replace all the bushings front and rear including struts and strut mount kits, if they "need" it or not. If you drive like a teenager, which i have been known to do" then maybe a little earlier than 100,000 if inside wear and cupping develops. I use moog bushings/control arms and kyb shocks. If you are going to do it yourself or have it done at a non dealer shop be sure the "preload" the suspension before you tighten everything up. Usually ends up costing about 500.00 per axle in parts then an alignment. i try to do it right before i replace tires so i can drive to the alignment shop on old worn out tires, closes one is 40 miles away, to ensure i dont chew up a good set on my way to get an alignment.

all the camber kits in the world wont help if when you hit the brakes it throws all the alignment specs way out of whack because of worn bushings.

cschroder

these are the usually the problem in the front:

http://www.rocar-usa.com/product.php...roducts_id=113

in the rear it is usually this one:

http://www.ebay.com/itm/LEXUS-GS300-...FRQLBA&vxp=mtr

ibidu1

iTrader: (1)

Great info!! I have been suspecting lower control arms for the rear as ive been putting off replacing them because of there cost. Ive replace all the rear bushings except that.

I agree also with you on using top chamber corrector, it will align on the rack but throws off the alignment when a bushings shifts a different angle.

350AWD

Good references, I checked the rear and everything was good, but my problem end up being the shocks. But I'll keep on eye on this in the future.