01 Is 300 Steering Shimmy

[dragr13]

My car has an interesting new problem; the steering wheel has started to occasionally shimmy back and forth (significantly) for short periods. It seems to be about 5 minutes after the car is turned on (hot or cold, after performing totally correctly for that first 5 minutes), when i throttle up to about 45 mph i can start to feel the wheel shimmy, then by 50 it is bucking back and forth (up to at least an inch of total travel), which continues until i slow down to about 40. the car itself is not shaking, it is still turning and handling just fine and not tracking back and forth, and pressing the brake actually seems to decrease the shimmy. then, after about ten minutes of the wheel jumping back and forth and me freaking out, i'll accelerate again and the car is totally fine. no shake. no shimmy. lexus operation.

I started to feel the shimmy in the wheel months ago, but it was always just a little tiny shimmy for a few moments a couple of minutes into driving and then it would go away, but today is the first day that the wheel really started bucking back and forth like that. Obviously, i'm not ok with this.

I don't even know where to begin. Does anyone have any thoughts, ideas, or advice?

[bartkat]

First thing to do would be to have the tires balanced.

[dragr13]

Well, yeah, i know that i have to go get the suspension checked; i've been planning to get some tokico adjustables pretty soon here and i'll do some ball joints and tie rod ends at the same time, but i'm pretty freaking sure that the alignment itself is still relatively ok, and not the immediate issue.

Car did the same thing this morning; i let her warm up for a good 10 or 15 before i left, everything was totally fine for literally 5 minutes (i was watching the clock), then when i accelerate up through 40 i start to feel the wheel shake, at 45 its definite, and by 50 its ridiculous. so i played with it a bit, took her up and down through the speed. above 50 the shimmy dies down significantly; it's still there, but not nearly as pronounced, almost like it is initially at 40. as i come back down it bucks real bad at 50 again and then gets better until it drops below 40, and then its gone. after 20 minutes (i *BLEEP* you not, it was exactly 20 minutes. i was watching the clock and the speedo more than the road) the car smooths out and DOES NOT shimmy anymore. i drove for at least another 20 minutes up and down through the speed range and on the same type of back in the valley roads and never felt it again.

So, i understand why you go to the tire balance (and if i can get into my buddy's shop i very well might balance them tonight, to be safe), but the car drives so normally both before and after that 20 minute period that i don't understand how it could be the balance or alignment. it's very strange.

Power steering fluid is perfect.

[bartkat]

The tires may be smoothing out after they warm up. After driving awhile the pressure is going to increase a little. If the tires have a folded nylon ply under the belt then that's going to flat spot and thump till it warms up too.

[dragr13]

jesus christ i finally laid down on the ground and looked underneath and the tires are worn on the inside terribly. i was waiting to put it on a lift to check it out but now i just feel dumb. she's supposed to get lifted tonight n i'll rotate n balance the tires and check the suspension out and let you know.

[dragr13]

ok, so the car may have some alignment issues, but it was the frozen brake caliper that was making her shimmy. frozen brake caliper! hard to believe, but at least i know i'm not crazy. i KNEW it wasn't the alignment!

so everyone remember that one: crazy unexplained (non-suspension) steering shimmy = frozen brake caliper

[NicLX470]

I have the same problem though it is with my LX470 above 45mph. For some reason I am constantly fighting with the tires to keep them balanced right. Sometimes the steering is tight and is free of bucking, then other times I have to hold on with 2 hands before it gets away from me. Also depending on the road surfaces. Every 3k miles when I get my oil changed I must get the tires road forced balanced. This is the only balance that will cure the problem though only temporary. My previous 2 4Runners did this also and I was never able to fix the problem. Are there certain tires that are made to be smoother and less prone to this issue? Currently I have kind of sporty / offroad Cooper Zeon LTZ's tires on my LX470. Maybe some maw maw type michilens will be better? I'm just waiting for these to go bald to try something new. My balance was PERFECT and the wheel never shook until the other day I got 2 nails in the back drivers side tire. I had it patched and now the steering wheel shakes again.....the front tires were not even touched except to remove front wheels temporaraly to replace the rotors which I had done the same time of the tire patching. So the only tire actually removed from the wheel was the rear drivers side. How could this make the steering wheel shake like this? It is possible an unblanced rear tire could also play a part in steering shimmy?

[baskinjaved]

i had the same problem occur to me a couple months ago. get your rotors checked...ended up that mine were warped/bent and that's what was causing for my steering wheel to do that.