sbgs400

ok so my car has had a high speed (65+) vibration ever since i bought it in july. it has gotten progressively worse and is really uncomfortable now. so far i have done:
-new ball joints and tie rod ends
-new rotors and discs
-new wheels and tires, balanced and aligned
-daizen control arm bushings

all to no avail, it's still vibrating like a ****. when i was doing the control arm bushings i had a look at the shocks, they look good, no leakage and they rebound properly (but that's not a definitive test). i have not done the steering pretensioner trick because i consider that a compromise rather than a fix and i don't really see how it fix this heavy vibration that i'm getting anyhow. i don't think it's the steering rack because the steering is good, it doesn't wander and doesn't make noises. i'm starting to wonder if it's coming from the back? any ideas?

maximussp

Did you get road force balancing? If so, I'm in the same boat with you. Can't igure out y it shakes. Makes no sense.

sbgs400

the place that balanced the wheels didn't have a road force balancer, i'm going to try another place tomorrow. another $100, *sigh*.

jonathancl

Road force balancing is necessary.

Tirerack.com will tell you what places near you have what machines (if you pretend you're buying tires and choosing a place to ship).

You can then look up how much each machine costs and go to the place with the most expensive machine.

I've also found vibration to increase over time as tire pressure falls...but that's not your issue.

chuckb

if they were road force balanced, they should have a number in lbs for each wheel that tells how well it's balanced. in general, those numbers cant be higher than low 20s for a smooth ride in our cars.

also, do you have aftermarket wheels?

sbgs400

i got the wheels balanced on a road force balancer last weekend. i was going to wait until i had a chance to go on a high speed run before reporting back, but i haven't had much time all week. the few brief times that i've gotten above 60 it seems really smooth. so i think that did the trick, the daizen bushings probably helped too. cost $28 to do all 4 wheels.

skyak

When you get your 98-00 GS tires balanced ensure that the tech (lexus or otherwise) has the attached technical service bulletin. I used to continually have vibration problems until I found this (the wheel balancing machine inputs need to be set up a certain way).

sbgs400

thanks, that looks useful. however i have 06 gs300 wheels on my car and they are 17x7.5, so the correction factor for 17x8 wouldn't be right.

bsmith203

iTrader: (1)

I have a similair problem with my 98 gs 400. However my car runs smooth throughout the entire 0- 90 mph range. The car for some strange reasons just randomly shakes when I change from different highway surfaces( aspahlt to cement). Have no idea where to start diagmositics

mole

iTrader: (3)

https://www.clublexus.com/forums/sho...d.php?t=244553

see this post as it discusses highway speed shaking and resolutions that havent been discussed here.

sbgs400

hope i don't offend anyone by saying this, but i don't consider that pretensioner adjustment to be a fix. IMHO that just covers up the problem by making the steering tighter. i'd rather fix what's causing the vibration first.

mole

iTrader: (3)

no offense, I would say I dont necessarily consider it to be masking the problem since the steering rack has slop built into it, and additionally, from what others have said, when lowering the car the vibration usually becomes worse. In my opinion, the pretensioner has an "adjustment", so I am I figure I should use it. But then again I am not super mechanically inclined and dont
have the knowledge many here do, so I am just using what I can.

Good luck on solving your issue and if you find out what it is, please keep us all in the loop so we can apply the same.

John

sbgs400

oh mine is fixed, all it took was the right balancer. i didn't adjust the pretensioner at all. of course my car has new ball joints, new brake rotors, new tie rod ends and new daizen control arm bushings as well. i'm sure those helped as well.

mole

iTrader: (3)

i just read this, your in the 2 gen section. I am not sure what would be different, but you may want to post where other 3 gen owners can help you.

sbgs400

mole my problem is fixed, proper balancing along with replacing worn out suspension components fixed it. my point was that doing the pretension may alleviate the symptoms but it doesn't address that worn out suspension components could be part of the problems. and it's a gs400, so it's a second gen gs.