Another wheel shimmy solution theory

This may have been discussed but I could not find it on a search. It is an older vid and I am not proposing it as a solution. Just want to hear what those of you that know functional mechanics of our beloved 4runners more than me think about it. Feel free to shout it down or ???

https://www.youtube.com/watch?v=Cg-hKIFdSMc

 

So now its the rack lol. jesus.



Its the tires.

/thread

 

I think it could be AN issue, but not the underlying reason so many people experience the 50-60 shimmy.

 

Yeah, I'm calling bullshit on that. Gives no background on the 4Rs that he "worked" on, whether or not they were lifted, upsized tires, etc. This dude advocates for throwing the parts cannon at a probable tire/wheel problem. And not just a small parts cannon, a VERY expensive part and labor intensive removal/install process. This is precisely why you don't trust these fools. Take it to an independent shop, always.

 

I think Ford has/had this issue with quite a few years of F150. People replaced everything-wouldn't go away.

 

Thanks for the sounding board. I guess I will keep playing with tires and balance. Riding well balanced Michelins now. No improvement. Must admit like many others it’s getting frustrating and definitely robbing from the consistent joy of driving. Hopefully will get resolved or may not be keeping it as long as I had planned, which was at least 200k miles.

 

Hmm..."save your time and money and go with an oem steering rack"???

 

Must admit I am not yet convinced enough to drop the coin on that. After all doesn’t it already have an OEM rack???

 

Some have had luck with using aftermarket lug nuts. Search around here, should be able to find the thread.

 

Done

 

Drive at 80, past the shimmy zone

 

Are you on aftermarket wheels? With the correct hub bore (106.1 mm)?

 

Lots of issues can manifest as vibrations that feel like a tire balance issue. Front diff needle bearing was the most recent cause of the majority of my shimmy I think the bearing might be an issue from the factory and so the slightest tire out of balance causes the truck to shake and lifts just exacerbate it.

Just recently cleaned up the mating surfaces between the rim, rotor & hub. Doing that cleared up pretty much the rest of the shake I was experiencing. Aside from bent rims I wonder if when someone says "new rims fixed the shaking" it was really just that the rim mating surface was corroded & uneven. Speculation though.

 

Might be part of it, but there are too many people, IMO, that have this brand new vehicles, for the mating surface to be the main factor.

 

I didn't think this post was about brand new 4runners, are people replacing rims on brand new 4runners to fix shaking?? That wouldn't even cross my mind on a new vehicle I was more so speaking generally. I also know that I had a reoccurring steering wheel shake on my 4runner that I bought at 48k, the thing that finally stopped it was the front diff needle bearing when several shops diag'd it as the steering rack.

 

The post is about cause of the shimmy. Brand new vehicles with stock wheels/tires sometimes have it and balancing doesn't cure it always. The same people sometimes throw on new tires, wheels or both and still have the vibration. In these cases I don't think mating surface of the wheel is corrupt. Other cases, as you pointed out, needle bearing could be culprit-less likely on brand new vehicle. I have yet to see a steering rack that was the root cause-excluding vehicles that were in a wreck.

 

I was just adding my 2 cents from experience, thanks

 

And that is valid. Anyone chasing this issue should make sure the wheels, hubs are clean and free of rust/debris, as well as installing and torqueing lug nuts correctly.

 

My '24 has had it since driving it off the lot. Same as everyone else; shimmy between 53-63 mph. Knowing about the condition prior to purchasing the vehicle (thanks 4runners.com), I wasn't overly concerned. I went to a local (competent) tire shop and immediately had all 4 tired road force balanced. Seemed to clear up some of it, but not all. It's annoying at times, but not a big deal; seems to be sensitive to things like ambient temperature, road surface, etc...

It had 13 miles on the odo when I drove it off the lot, so no issues with corrosion on the mating surfaces. Looking at replacing the needle bearing since that has been successful for many of the folks here.

 

I am on aftermarket wheels. But was the same on the stock wheels.
EGCS Needle bearing replacement just delivered. Hopefully installing next week.
Would be very nice if that solves it.

 

When I had vibration responsibility for an OEM this specific vibration (steering wheel oscillations) was called "nibble". It's managed two ways...by setting targets for tire/wheel excitation and also for vehicle sensitivity to tire/wheel excitation.

I've never seen (or don't remember) seeing standard test data for vehicle sensitivity for a 4R but based on the fact that quite a few people get the vibration I'd guess the vehicle is more sensitive than average. There aren't a lot of options for changing vehicle sensitivity in a vehicle that's in production...and although I didn't watch the video something like rack friction could have a small influence on vehicle sensitivity.

On the excitation side stuff like lug nuts and wheel/hub fit may have a small effect but the main culprit is tires...there are a hell of a lot of ways that tires can create vibration. You say that your Michelins are well-balanced. I'd ask you what the levels of R1H are for all four tires. All tires have specs for R1H (radial force variation) and in my experience LOTS of out of spec tires can find their way into vehicles. Even if your tires are within spec for R1H, if both front tires are near the spec limit you may well get vibration.

Tire/wheel assemblies get a "road force" (R1H) balance at the factory (in addition to a traditional balance with weights) but all this does is line up the "high point" (stiffest part) of the tire with the "low point" on the wheel (which are never perfectly round) to do the best job possible of cancelling the forces from the tire high point and wheel low point. If the 4R had perfectly round wheels this trick would not work at all; it's an imperfect process compared to a traditional balance with weights. At the end of the day you want tires with low R1H and that's why I'd be curious if you know just how good or bad your tires are for R1H.

So even on a new vehicle it's not surprising if balancing doesn't always work; if it's an R1H problem a balance with weights does nothing and if it's an R1H problem even a road force balance can't be expected to make the tire/wheel assembly perfect every time.

 

Hey guys, I too have the intermittent front wheel shimmy. I was searching through Google came across this Thread.
I know I am brand new to this form and this is my first post. However, I have been a car guy pretty much all of my 48 years of existence.
Couples things i’d like to add are:
- I don’t disagree with what “Gumpus” said above which is why even though I’ve had discount tire attempt to rebalance my current wheel tire combo two separate occasions. I am still going to have an old mechanic buddy of mine do a road force balance for me while I am there watching, to hopefully minimize the wheel & tire causes of vibration as best as possible.

However I will also be purchasing The East Coast gear supply (ECGS) Clamshell Bushing. After watching the videos, they posted on there website. I think it’s pretty obvious that it is a Very strong possible root cause of the issue. Assuming of course, that everything else is mechanically sound on your specific vehicle.

Mr. Gumpus, I encourage you to watch this video as well and report back.

https://eastcoastgearsupply.com/i-8...bushing-eliminates-needle-bearing.html#videos

 

Lots of good ideas provided here. I have not suffered your particular problem yet. I found a good tire shop decades ago and always purchase & service my tires with them. I gave up on trying to get tire/suspension services from dealers. It takes talent and experience to do job correctly.
I only had one balance issue where a new guy did not remove the old weights when I did a rotate & balance. The owner personally overlooked the re-balance which provided smooth driving. Of course road surface affects steering wheel shake/shimmy, but on a good road surface my truck is smooth at any speed.

 

Very informative post! I’ve always suspected that the steering wheel “excitation” issue (I love new vocab for stuff like this ) issue is due to multiple factors. Particularly the general steering geometry of the 4runner, and the soft bushings in control arms, steering rack, and body mounts. While soft bushings make for a very comfortable ride, they probably allows a lot of “space” for harmonics to amplify.


I don’t have a steering wheel oscillation issue, but it has happened to me for about one minute at slightly lower speeds 40-50mph. But it’s only happened a few times in 70k miles. Probably a flat spot from sitting, a pebble stuck in the wrong tread, air temperature affecting flex of the rubber, or some weird variable like that was what sets off the harmonic, because it’s never lasted more than a minute or so.

I’ve seen others post about the theory of the needle bearing steering wheel shimmy, particularly with regard to tacomas. But I don’t really understand how it could even contribute to shimmy, much less cause it. I can’t visualize how noise/vibration from the slop from the needle bearing translates itself into side to side steering oscilations. Maybe it’s possible, but I haven’t heard a convincing mechanism for how that could happen.

I tend to get needle bearing noise at times, largely during cooler fall and springtime outside air temperature. But, I’ve never gotten any steering wheel oscillation when it does make noise.

I saw the video on the steering rack earlier in this thread. A new steering rack to solve a steering shimmy seems like a very expensive way to *maybe* solve this problem. It could just as easily have been that the new bushings changed the natural frequency of the whole front end. It’s great if it solves it, but it still seems like trying to balance (or verify roundness) is the best way to try to solve this problem, because it’s a trigger that has the most mechanical leverage over the whole front end.

 

At one point in time Ford & Toyota quit using "steering dampers" "steering stabilizers", at least Toyota did. The later part of the 90's from what I've seen. I used to go 4wheeling with a few guys years ago, and the 1 fellow had a Ford 150 with 36" or 38" tires and when he went down the road this thing would shake bad, so 1 of the guys said "you need to put on a new steering stabilizer." He actually got a twin stabilizer kit, put it on and the shake went away. My Dad's 1977 F-150 had a shake at 1 point in it's life, new steering stabilizer shock.. fixed it, it had stock sized tires and rims (farm truck) My old Toyota(1986) pickup had a stabilizer shock on the steering, aftermarket wheels and 33" rubber, never had issues with it. Now we tried out a new 2020 4Runner off the dealer lot, and at 45 it shook bad. It turned out to be a 'balance' issue. I think the steering stabilizers of years gone by compensated for imperfections in balancing, alignment, and maybe wear. Just a thought.

 

Please explain with more detail. How much out of round and how did you determine this?

 

I think stabilizers are only used for solid front axle vehicles to prevent death wobble, which is much a much higher energy oscillation that can actually lead to stuff breaking off very quickly if you don’t stop the car. Often times the oscillation starts after a bump in the road sets it off, but if it has a bunch of worn bushings in all the linkages, it can develop on its own.

A buddy of mine had his jeep go into death wobble for the first time recently. Scared the crap out of him because he basically went from being in control to out of control from one second to the next.

 

Yep,, I hear ya. This is a good theory except my '86 Toyota was I.F.S.. The other trucks like the F150 was a solid front end.. correct. The Toyotas I mention though are I.F.S.... FWIW.

 

Valid point! there shouldnt be a over generalization with comparing a solid axle to a IFS. completely different can of worms.

 

Will the modern day steering rack play nice with the steering stabilizer? It's certainly a thought.