Hello all,

I know that this topic has been discussed before but I recently purchased a 1998 GS400 and whenever I am going around 60 mph, the steering wheel would start to shake pretty badly.

I took it to Lexus and I got the tires balanced as well as got the brakes changed too. The car has basically brand new tires, but the tech told me that I have flat spots on my tires. Would that really cause the shake only when I am going 60 mph and not any other speeds...?

I was wondering if tightening up the steering pre-tensioner would help at all with this issue or would it be only the flat spots?

Any help is greatly appreciated as I know this issue is pretty common with these 2GS,


Huss

 

 

How are your front upper control arms? The rest of the suspension?

 

Have the same issue, actually just got worse today. Almost as soon as I hit 60 or 65 mph it starts shaking. I'm going to replace the sway bar and steering rack bushings with Daizen ones and see if that makes a difference.

 

Do exactly what I did. I practically changed my upper control arms. Lower ball joints, sway bar links & put another rack & pinion in my car & it still shaked at highway speeds above 55. I went to the salvage yard and got me some caster arms off a 2001 GS. Then ordered superpro caster arm bushings. Any machine shop can remove the old bushing. Torch it out and it pops out. In stall the new bushings, properly grease the bushings with the supplied grease & install on your car. Highway shake, vibration and wandering all over the road will instantly cease. I just did mine last week and my car rides like a dream now. You guy won't be disappointed. $40 or $50 for the arms depends on pricing in your area, bushings cost $90, & I paid $50 for the machine shop to press out the old & reinstall the new bushings

 

Are you saying to get the 2001 GS caster arms or just to get new caster arm bushings? If it's as easy as that then I'm glad. Definetly not trying to go through what you had to.

 

Did anyone answer his question about the bald spot on the tires? (I'm not gonna read the whole thread for that)

OP, YES, that bald spot can cause vibration at a single speed. Its basic physics. How do i know? Been there, done that.

Are there flat spots on all 4 tires? I'm willing to bet you or the previous owner slammed on their brakes or if its just 2 tires, slammed on the e-brake while effing around. Thats really the only thing that would cause that. ABS lights on?

If its just 2 of the tires, swap them front to back and see how it changes the shake. To save some $$, you could put the tires with the flat spot in the rear and do a few burnouts until you even the flat spot out with the rest.

Got any other wheels to throw on to confirm that it is what I've mentioned? thats the cheapest way to do it. Wobbles can quite literally be like 50+ different things and not a great idea to ask on a forum, thats a good way to waste a LOT of money doing suggestions one by one. You need to get a professional to do an inspection and find exactly what it could be.

Want another suggestion as to what it could be? Could be your carrier bearing. Thats where "I" found my wobble at, a very small crack in the rubber. Nowhere near a suspension component... Again, could be anything. need a professional; well you got the info from a professional already.

As for wobble being a common issue with the GS... Nah, thats a common issue with cars in general. Busted ball joints... Now THATS a common GS issue

 

I'm glad I did it bcuz buying new arms cost more.

 

Sometimes the simplest adjustments can make a lot of difference. Check your tire pressure and make sure they are all with in 1 psi of each other. If you have low profile tires it is even more important. Don't use high pressure either, 30 to 33 psi is fine.

 

Where do you get this from? Regardless what tire you use, its relative to the weight of the car. Simple physics dictates that the heavier the car (thus creating a fold in the tire from the weight) requires more air pressure to keep the tire evenly placed on the ground. Tires need to be filled to the manufactures recommended psi, regardless if low-pro or not. Also relative to the application and use of the vehicle.

 

Where do I get this from? Well it's on the door jab of every car...even yours!
​​​​​​You’ll find the manufacturer’s optimum or recommended tire pressure for your car on a sticker in the door jam, or in your owner’s manual. Some models even place the stickers on the trunk lid, in the console or on the fuel door.

Recommended pressure is usually between 30 and 35 PSI. That number indicates the minimum amount of air pressure needed to support your vehicles maximum load-carrying capacity. Any less, and you’ll see poor fuel economy and handling as well as premature wear from too much flexing and tire overloading.

When your tires are inflated to the recommended PSI, you enjoy their optimum life and performance.

 

Hey Kevin,

I actually got my rear pads and rotors changed, as well as got the front rotors resurfaced. And yes my tires are new but I think the flat spots are starting to play a bigger role now with the issue unfortunately.

Thanks for your input,


Huss


Hey Doc,

My upper control arms seem to be fine. No problems or issues with them as well as the rest of the suspension. The mechanic said that the bushings seemed to have been replaced as they were fairly new. Any other ideas?

Regards,


Huss


Hey Mr. Jokster,

Really? The flat spots would cause the steering wheel shaking at those speeds?

Regarding why the car has flat spots...check it: I bought the car from the original owner and she barely drove the car. It was a fairly old lady, the owner, and she had an LX470 as well so she just needed extra garage space. The car has 131,000 miles on it, and it is a 1998. So...the car has been driven an average of 6500 miles a year. LOL! I wanted a low mileage car...and, uh, that's what I got. And yes, I have the flat spots on all four tires.

What I think I am going to do now is try to get some other tires and wheels on the car and see if that issue still persists. I also will take the car back to the shop and have them check the carrier bearing. Who knows? That could be the issue itself

Thank you for your insight, Mr. Jokster,


Huss


Hey Steamboat,

Actually...funny thing is is that the tech who was working on the car said that the tire pressure was extremely, extremely high on the car. I believe he mentioned around 50 psi...I highly doubt that they were but...again, who knows? He changed em and matched em all up to be the same pressure.

Thank you and I will try to not overthink it and check the small things,


Huss

 

Thanks everyone for all of your replies!

I wanted to wait until the winter to get some new tires and wheels, but I think I'm going to get some cheap wheels and see how they fair on the car. Hopefully, that will take care of the issue.

Regards,


Huss

 

The high pressure in the wheels you mentioned could have cause them to bend. So it might not be flat spots, but the tires bent because of the steel band inside of them.

also, try changing the front sway bar links. That fixed my issue. It's cheap enough that if it doesn't fix it atleast you know you can rule it out. The parts are about 80 dollars for both.