bwilder10h

I bought my car a little over a month ago with 57k. With the stock wheels, the car shook on the highway over 70mph and the wheels were curbed pretty badly so I assumed one was bent.

I've since bought 20" wheels and the vibes are much worse (no surprise right)

The car starts to shake around 50 but sometimes 40 and the weird part is it doesn't do it all the time, nor does it shake constantly from 40-80. There are speeds where it is better or worse than others.

Today I took the car to a local tire shop and they rebalanced the wheels twice on a road force machine and it is slightly better but still not good. The steering wheel shakes so bad at 60 it's ridiculous.

Given the issue happens with both sets of wheels, I've ruled them out but when I asked the shop to check the tie rods and ball joints, they said everything was tight and looked good.

Suggestions on what to try next? I've seen all the posts about ball joints, steering rack adjustments (which I dont know if mine has being a 98), tie rods, etc, etc but I dont want to just throw expensive parts at it and not resolve the problem. Dont have endless $ supply...

carbongs

iTrader: (13)

someone else had a mechanic tighten up all their bolts to spec torque. then it could also be your steering shaft pretensioner. that was a common issue.

UZ214

i had to balanced my wheels 3 times in my GS400, before i found a better shop to do it, basically you need to go to place where they know what they are doing, go to different shops they need to use the newer HUNTER machines with updated software or something that what the tech told me...so good luck

06CWIS350

most likely its your castor arm bushings. These go bad after 60K miles. Try searching bushings and youll find thats what most gs4 owners found as the solution. Oh yeah make sure you got hub centric rings and oem lug nuts... also u need to get ball joints and tie rod ends anyways... might as well do it all at once, i wish i did..

SoCalSC4

Are the hub-centric rings installed in your 20s?

What brand of tires on both sets of wheels?

Giggzz

I just replaced my castor arm bushings today and it does help alot. Im waiting on my Dazion bushings to come to do the rest.

GeorgeGS4

99% of car vibrations are caused by bad balancing or bad tires. I'd recommend taking it to a different shop like someone suggested. Get someone TIA certified and only with the Hunter balancing machines. (they're most accurated on where to place the weights) Anything more than .25oz off and you will feel it while driving.

A wheel can balance out and have low road force, BUT still be warped, too.

Is the vibration coming from the seat or the steering wheel? If it's the wheel, it's coming from the front, if it's the seat, it's from the rear.

Did they check the condition of the tires? For instance, heaving scallopping on the shoulders or a belt seperation/shift will also cause a vibration. Just know what to ask for when you go in there and make sure they know what they're talking about. good luck

bwilder10h

The tires on the stock wheels were Pirelli's that I had road force balanced. The tires on the new 20's are Kumho's and are incredibly quiet. I've had them on the last two sets of aftermarket wheels I've purchased and they are awesome tires for the money.

At this point, I'm pretty confident it's something on the car. The hub centric rings made no difference, nor did centering the wheels carefully and torquing to 76lbs.

How do I know what bushings/parts are bad? I dont want to go throwing parts at it and end up spending tons of money.

What do the castor arms look like?

Giggzz

See here Castor arm1
and here : Castor arm2

From what I have read there good for about 60 - 70,000 miles, mine had 125,000 so thought they were due. It does make a difference in the handling, the front end feels firmer. I will also be changing my upper control arm bushings when they arrive.

Hope this helps

DaveGS4

iTrader: (2)

Some folks have also reported that slightly warped brake rotors can cause the shaking issue.

From many member experiences (and as posted above) , the newer Hunter machines seem to be the one that does the best job at balancing. If you don't know what your shop uses ask - the model numbers are posted in threads here (just search for hunter in the 2nd gen gs forum).

bwilder10h

Thanks for the posts showing the castor arms. Where is a good place to get those and is there a way I can tell if they are bad?

sputniknyc

iTrader: (2)

our vendor

http://www.lexus-parts.com/partdetai...bCategoryID=85