Yes thats kind of scary :/ ! I don't disagree with the design, just think it needs something in there. Don't know what yet! anyways thanks for your input, if you ever figure it out let me know ill try a few more things to see if anything helps!

 

bimmer
its on all cars. that's why they tell you to always check your ball joints.

 

Yup, had to replace mine for the second time now because last ones got worn out fastt : /

 

Highway vibrations with lexus vehicles usually fall into three categories: wheel imbalance, road force variation, and (particularly with '10+ GX460 models) suspension harmonics. The Sc suspensions tend to absorb road irregularities fairly well, but have issues with the heavy, easily bent OEM wheels and stiff runflat tires. I recommend a quality set of aftermarket 18-19" rims with quality non-runflat tires for a better ride. Lexus does sell(or did) a compact spare kit that can be installed in the cargo area. I have driven many sc's and this seems to be the best solution. The GX's, as mentioned in a previous post, are another issue entirely and have more to do with suspension harmonics(even though Lexus claims the steering gear TSB helps). To all you SC owners out there with vibration issues, keep track of when it occurs; cold tires?(roadforce) rough patch of highway?(suspension) 50-65mph?(tire imbalance) this will help to narrow down your concerns.

 

Same here. I replaced aftermarket rims with oems Friday and it cleared up the vibration. I too had a low speed vibration between 45 and 55 and when it passed 55 the ride was so smooth I would soon see 85. OEMs are best for a smooth ride.

 

Well my oems must definately be bent because it rides really bad with those but my aftermarket wheels are good and I think the recommended tire size by lexus is wrong on the oem, the tire is too wide and tends to direct the wheels. As for the vibration, it doesnt seem like its because of the wheel or tire, I have changed alot of stuff, got rims switched from one side to other, brand new tires but its mostly on my right side and it feels like the suspension doesnt hold the wheel properly or something, its really wierd and there is also this up and down hopping sometimes. Not sure what to do :/ i mean its definately better then before but sometimes its just so bad that it feels like your driving a shed rather then an $80k car :/ I think I should also change the rear bushings though, might make a difference

 

I had this problem on my SC430 when I bought it 18 months ago with 11K original miles on it. The car was practically brand new but two of the wheels had slight lip bends even though there were no signs of impacts. I had them repaired at Wheel Techniques in San Jose.

The SC430 is very sensitive to any slight wheel imperfections, out of balance tires, and out of round tires.

Jack the car so that one front wheel is off the ground. Rotate it. Look for spots where the rims on the outside and inside move in or out. They should be within 1mm of true. Next look for out of roundness on your tires. Some are worse than others. Repeat on the other side.

Then jack the rear up by the center diff and and put the trans in neutral and do the same checks. Rear wheels/tires won't cause the shake as much in the front but they will still do it.

Make sure your tires are roadforce balanced and they must be done at operating temperature. The balancer should run the wheel applied to the drum at highway speed until the tire is up to temp and then the tire should be balanced.

Any of these will cause a vibration at 65 which is natural frequency for this diameter wheel to show any balance or trueness imperfections. People spend way to much time replacing steering and suspension components without looking at wheels and tires first.

 

Count me in I get vibrations too! Especially when I go close to 40 - 55 and after that It's pretty smooth.

 

My '02 with 82K miles has factory rims (no curb rash or damage) and doesn't do any of those vibrations at any speed. Have had it up to 100'ish MPH also with no noticable vibration although I was preoccupied with getting back into my lane after power passing several cars who insisted on doing the speed limit

I'm guessing that this might be something that I get to look forward to as the car ages or with the next set of tires if not properly balanced? I've never heard of road force balancing so I'll be sure to inquire about that!

 

It has been almost a year, are your issues resolved satisfactorily? I am asking because I have the same thing, more noticeable on rough roads (20/30 miles/hr). I put in 2 new front tires Ponteza RE760 245/35/20. has been rebalanced twice. What would U suggest to fix it?

 

Well I finally fixed mine today!. I have OEM rims for my winter tires and Dolce rims (stock size) for my summer rims. No matter what tires, no matter who balanced them I would get the same shimmy from just before 60mph up to about 65mph and then smooth as glass. I tried the urethane steering bushings which did not help. The car just passed inspection which includes a full suspension component test . I also just had 4 new summer tires installed on my Dolce rims. Nothing made a difference.

Then when I was under the car replacing the rack bushings I looked at the rack and it reminded me of my Infiniti FX45. I had the same type of shimmy on that car....maybe a little worse. The fix for that car was a pre-load adjustment on the steering rack. When I looked at the rack on my SC430 there seemed to be the same adjustment spot.

Here is just one FX write up (there are others):
http://www.infinitiscene.com/forum/t...el-shake-fixed

What I did was mark the inner section in relation to the outer housing of the rack so I knew my starting point. You are better off adjusting it too little then too much. I needed to apply a little heat to the locking ring to make it break loose. Since I didn't have a special tool to fit inside the rack I found a nut that fit inside (it fit a 15/16th socket) the rack so I installed it halfway into my socket and the other half went into the rack. I turned the inner section clockwise (facing the front of the car) about 1/4" (not 1/4 turn...about 1/4 inch) and my shake is virtually gone. I think I might turn it a bit more but I want to get some highway miles under my belt first. I got it up to 65mph in town for a brief few moments and I maybe, just maybe, felt a whisper of a shake. Nothing near what it was like. The car also returns to center as it did before.

When i did this to my FX45 I put over 60,000 miles on it with no issues.

 

Just a quick update. I took the car on my regular 50 mile commute to work this morning. About 25 miles on the first section of highway where I normally drive above 65mph. My acceleration through the 60-65mph zone showed absolutely no wheel vibration.

The second stretch of highway is about 10 miles and most of the driving is usually around that 60-65mph speed. The road is also different in that the worst shaking always occurred on this road. I don't know if it was how it was constructed or what but it consistently shook worse on this road.

I am please to say that the shake is 99% gone. If I didn't know it was there before than I would say it was 100% gone. There might have been a very, very, very little shake for a few moments but it might have been me just looking for it.

So after 3 different sets of tires, alignments, two sets of rims, new brakes (with rotors) and the urethane rack bushings I can now say that with this simple adjustment my car feels great.

And to clarify how much of an adjustment I made.....If a 1/4 turn would be 90 degrees then I would say I turned the center section a little less that half of 1/4 turn.

Try it...its free and easy to do.

 

Good to know jspbtown. Thanks.

 

Hi Prasha, im going to answer that in 3 weeks.. I have just added coilovers now im waiting for my suspension parts to come in including the upper adjustable arms.. once installed and allignment/road force balancing done, i will let you know how it goes and everything I dealt with from the past.

You are the second person to mention this aside from v300graham on my thread long ago:
https://www.clublexus.com/forums/sc-...bushing-3.html

many do not agree but after looking at suspension designs of MANY cars near SC's weight, I find that the SC's suspension weak for its weight.. with one MAIN joint above and below... the secondary stability joint is PUT uppon the steering rack tierods.. which are what keep your wheels in same angle both sides.. unfortunately with uneven roads and angles, the wheels pull in different angles and the tie rod ball joint arent capable of keeping them straight and thats how you feel everything thru your steering.. (an easier way to explain is that the steering is not only taking care of your turning but is also playing the role of a control arm) ....My steering was very dangrous at one point.. I would have to hold it quite hard that I would have the steering imprinted in my palm.

Now that the suspension design cant be changed we will have to try different things to see what helps and steering dampening looks like it would definately help.. so thanks for sharing your experience also.. I will also attempt this soon and get back to you guys!

 

I'm still good, no wobbles have returned, car steers like a go-cart, plenty of feel and nice kickback on bad roads, but no wobbles or shimmys.