Diagnosing front wheel shaking/wobble at highway speeds
 

Hey all, I've been trying to diagnose a front wheel shaking that been going on with my 4x4 Blazer for about 18 months now.

When it first started, I thought it was a wheel balance issue. I took it to Pepboys where I bought the tires to have them re-balance it, but they said the balance is fine.
The techs at Pepboys then showed me that the tires had begun to cup on all 4 around the inside treads of the Cooper Adventurer A/T tires I had at that time. They explained to be that the cupping was caused by bad shocks, and that the cupping is causing the shaking/wobbling/oscillation when driving at or above 55 MPH.

Taking their diagnosis to heart, I then began planning for new shocks and tires over the next few months. I bought new Bilstein HD shocks (the old OEM Bilstein's definitely were worn out), and after that I replaced the Cooper Adventurer A/T tires that were severely cupped with a new set of Cooper Evolution H/T tires. I opted for highway efficiency this time around since that is all the driving I ever do.

After test driving the new tires, the shaking/wobbling was still happening. My father, who had worked on older Chevy's most of his life, says it's the ball joints that are causing the shaking at higher speeds. So we began planning to rebuild the whole front end. Ball joints, bushings, and tie rods were all replaced. Spent about 2 weeks on this and finished today. We also packed the front CV axles with fresh grease while we had everything apart. I was fianlly able to take it over to Pepboys to get a proper alignment done and I gave it a proper test drive.

20 miles later at 70 MPH, the shaking is still happening. So now I'm at a lost to what could be causing the problem. Any thoughts?

Here's all the work I've done so far.

• New brake rotors and pads about 18 months ago
• Wheel hubs/bearings replaced about a year ago
• New shocks installed about 3 months ago
• New tires installed about 3 months ago
• New ball joints, bushings, tie rods installed about 1 day ago

Could CV axles be out of balance? I don't how to check that.

I also have concerns about the wheel hubs too. Is it possible that these can go out of balance?
These hubs are from Detroit Axle, and I've expressed in an earlier thread about how bad their quality control is when I bought their front end suspension kit.
I'm worried these might be worn out too because of how cheap they are. But even for cheap ones, they don't wear out that fast, do they? I've only had them for about a year.

I'm going back to Pepboys to have them check the wheel balance again. I didn't see any weights that popped off, but I don't know what else can cause this behaviour.
The wobbling is definitely something that feels like the wheels are out of wack somehow.

You should be able to test the hubs yourself to see if they are loose.

You didn't list the idler arm or pitman arm as parts you replaced. The OE spec idler arms are nortorious for wearing out so that the center link can move up and down which allows for some steering free-play for the front tires, in particular on the right side. If you do replace the idler arm, use a Moog or Proforged one as they have a more durable design. I've only ever rarely heard of the pitman arms needing to be replaced.

Did you replace both ends of each tie-rod?

Probably less likely, but have you checked your steering gear and rag joint?

Idler arm is what I would look at next if you haven't. And I would check the hubs, as cheap ones dont usually last.

Switch fronts with rears - same sides as a diagnostic

I did. They seem to spin okay.

Yes.

No. I'm not sure what those are.

I'll look into these next.

What about the center link? Would it cause this behavour too? I was browsing parts on Rock Auto and notice this part has greasable fittings too.

I looked at some quick videos on these parts. Would these parts only be related to steering sloppiness and handling?
My problem isn't steering wheel wobble or shakiness. Yes I feel a noticeable vibration in the steering wheel, but that's because the whole vehicle is vibrating/wobbling/oscillating/shaking.

When it comes to diagnosing vibrations and wobbles, it is hard to do via the web as one person's wobble is another person's vibration. But you say the whole vehicle is oscillating?? That is weird and definitely should not be happening. It sounds like some sort of resonate phenomena, like with an unbalanced wheel, but more. Did you have the rear wheels balanced too?

Did you figure out what a rag joint is? I should have used a better name. It is the joint between the steering wheel shaft and the steering gear.

As for checking those other parts, I would say you might as well.

You said the center link has greasable fittings? I would think those fittings would only be on the things that are attached to it; e.g. the idler arm.

What wheels (rims) are on that Blazer? OEM ones? Or some aftermarket?
Are the wheels running true? (lateral and vertical, when checking on the rims)

What Christine said. Post a picture of the cupping but idler arm had been a Chevy wear item for decades.

George

Long shot...


I've had ujoints on my driveshaft go, wear the yoke on the rear axle. That created a shake/vibration.

also, do you have any play I the rear wheels going to the axle? Maybe any signs of fluid arou d where the axle bearing is on either sides?

I know its front end, but could travel.

but I dont think the center link itself would be an issue. But the idler arm and the one on the end of the steering box.

This is a classic case of where proper diagnosis is essential to avoid the parts cannon. You analyze the tire wear as a starting point then go through the suspension and steering components one by one looking for play using a pry bar, jack, stands, hand cranking, etc. If bad shocks are involved in the wear then its because old shocks stopped damping the oscillation from worn parts in the first place. As I mentioned in a previous post, I agree with Christine that you need to evaluate your steering components with the idler arm being a prime suspect. There are plenty of you tube videos on checking everything but steering is one of the easiest. Jack up one side only and try to create side to side play at the wheel and see what you get. Our 2012 Malibu is the first Chevy I have ever owned that did not need an idler arm by 75.000 miles.

George

Wow George that’s surprising. I have never had to replace one on any of my GM vehicles over the past 40 years. Front ends were religiously checked re-greased with #2 every 3k miles.

Yes. I had all 4 balanced when I got new tires installed. Yes I didn't check mine. That's what I saw on Rock Auto for mt model Blazer. These are the OEM wheels for the 2002 models that have the console shifter (which mine has). They have cosmetic imperfections, but they're still structurally sound. Do you mean is the caster alignment good? I was told that the passenger side caster was maxed out and couldn't be adjusted, but Pepboys assured me that the alignment is good. Here's the diag print out they gave me.
https://cimg9.ibsrv.net/gimg/blazerf...46c77c6135.jpg
Here's the previous tires I had with the cupping. I still have these A/T tires. I'm currently running H/T tires I bought new.

​​​​​​
https://cimg4.ibsrv.net/gimg/blazerf...326c8d9ae8.jpg


Inside tread top of image.
https://cimg7.ibsrv.net/gimg/blazerf...7bfb32366c.jpg
​​​​​​​​​​​​​​I didn't check for play, but I can. No signs of fluid. I just changed out the diff oil recently. ​​​​​​​​​​​​​​

My wife mostly drove the Malibu, maybe that's the issue. She drives much more conservatively than I do. LOL.

George

The angle on those tread wear pictures is not great for seeing the problem. Is it inner or outer tread blocks that are ramped or is it cupping spread across the entire tire surface?

George

Malibus were nice cars, I remember I had an early eighties one of them with the 3.8 in it. I think the most I ever had to do to that car was valve stem seals. I can still remember finishing up the job and installing clips on the rockers so I could adjusti the valve lash while it was running 🍻

Sorry for the bad photos. I currently have the tires stored at a remote site.
It's the inside that's cupped. It's not really visible, but you can feel it.

Is it every so many tread blocks or are they all kind of ramped?

George

I just gotta say, this previous post shows some "Ninja-Level Multi-Quoting" going on! :icon_clapclap:

Sounds like you have systematically eliminated several culprits. But I know I've been tricked several times by where I thought a noise or vibration originated.

It appears to be vehicle speed, not engine speed dependent, which means that it can include all four wheels, the front suspension and steering components, and rear drivetrain.

It just occurred to me that perhaps the mounting bolts for something have come loose? This doesn't seem to fit the resonance behavior you are witnessing. I mention it because I'm running out of suggestions. LOL I once discovered that the bolts to a ball joint had worked themselves loose. It was right after I got the truck and I had a shop do the work for me. (Yet one more event that made me restart doing my own work again.)

I'm liking the suggestion that perhaps there is something going on with the driveshaft or components attached to it. Is the transmission output yoke loose?

I also wanted to ask if perhaps the torque converter was not working correctly. But then you reported that there was that weird tire-wear on the front tires which would suggest that the problems are in the front suspension. Ack! However, it wouldn't be the first time there has been more than one thing going on.

Did you recheck the hubs for any wobble? There should be no detectable free play and the only motion they allow is rotational.

In reading over this, the items I did not see that were checked or replaced were the upper control arm bushings, upper or lower ball joints, or lower control arm bushings. The lower ball joints take all the weight and wear. Upper ball joints pretty much last a long time.

It's less spammy if I can answer everything as I see them, lol.


I'm guessing it could be engine mounts then. I feel a bit of a shake at idle engine speed when stopped at a traffic light. But, reving the engine in netrual nutralizes that idel shake, so it may not be a contributor at highway speed. Regardless that's something I should check anyway.


I'll respond with a video where I'm checking it. I did check them, but wasn't sure how exactly they should feel. They seem fine to me.
https://drive.google.com/file/d/1bf_...ew?usp=sharing


I wouldn't think it's not working right. The whole transmission still shifts very smooth for the it's age.


Yes. They seem fine. No lateral play at all.


I did replace bushings. just forgot to mention. The upper control arms were replaced completely while new bushings were pressed into the lower control arms.
The driver side bushings were really worn out. Passenger side bushings were fine, so that lower control arm was left alone.

Update on the shaking. It seems to have mostly (if not completely) gone away.

i took it back to Pepboys to have then double check the wheel balance. The tech working with me did say that all 4 wheels are very slightly off balance.
He said that the previous guy who installed my new tires (same store where I bought the tires) didn't install the weight correctly, so he took them all off and reinstalled new ones on the outer rim.
It feels much better now. Any vibration now is definitely from the road.

https://cimg5.ibsrv.net/gimg/blazerf...d437a1bd2c.jpg

Rear issue possibly
 

Observed same issue years ago in a car. After exhausting all issues up front moved to rear. Finally replaced rear rotors that took care of vibration. Thought for sure issue was in front, funny how vibration transfers in a vehicle.

Did you happen to notice how the wheel weights were previously installed?......Trying to figure-out how the weights could not be installed incorrectly....wrong place on the wheel, okay...but ???....unless they were against the tire instead of the wheel??

Good to read the vibrations are gone.

You know, I might need to check into this too. My rear rotors are definitely due for replacement. I replaced the front ones over year ago.

The weights before were more or less how they are now. Just only on the inside. The tech said he pulled them all off and re applied them. Seems he added more.

I'll post some photos of the weights, cause it seems odd that so many were needed. The passenger side has the most.

https://cimg6.ibsrv.net/gimg/blazerf...a7ff7924f0.jpg
Rear passenger with these strange inner-rim weights.


https://cimg8.ibsrv.net/gimg/blazerf...3899b48257.jpg
Rear passenger inner weights.



https://cimg9.ibsrv.net/gimg/blazerf...d26b1a0df6.jpg
Rear driver inner weights



https://cimg0.ibsrv.net/gimg/blazerf...9fd0bc02a5.jpg
Front driver inner weights



https://cimg2.ibsrv.net/gimg/blazerf...88a558ddd2.jpg
Front driver outer weights.



https://cimg7.ibsrv.net/gimg/blazerf...7ce1037673.jpg
Rear driver outer weights.



https://cimg8.ibsrv.net/gimg/blazerf...8de9a5961e.jpg
Front passenger outer weights.



https://cimg9.ibsrv.net/gimg/blazerf...b62548a14f.jpg
Rear passenger outer weights.

Wow that looks like @ss. Who the hell puts clip-on weights onto the outside of an aluminum wheel.

On a more constructive note, that is A LOT of weight. Normally tires need no where near that much to true up. I’m thinking the idiots at pep boys probably should have mentioned that to you, but it comes as no surprise.

I’ll take a bet you’ve got a problem with at least one of your tires. Excessive heat and other issues can cause the tire belts to squirm or begin to delaminate; sometimes this isn’t readily visible.

Your felt vibration may be another issue altogether, but I’d take my bets on a bad tire.

I've noticed that using that many weights is a cause of a) a bent rim, or b) the tire bead isnt sitting right, they should have let the air out and turned the tire 1/4 turn on rim.

hey Don, at first I was thinking bent wheel too, but the wheels don’t look damaged, so that’s unlikely for an aluminum wheel. I never saw a bead not sit right, but I only did tires at a garage for a year or two when I was a kid. Usually they’d pop right in once you had enough pressure behind them

Sorry I guess I wasnt really meaning the bead.

I guess I mean more the imperfections of the rubber walls. I used to do tires in a mechanics shop and a tire shop (a couple of years total). The older guy in the mechanics shop I worked in, would tell me to take the weights off and turn the rubber and try again when theres a bunch. Any time I did that, I used less weights the second time.

yep, sometimes taking it off the bead and spinning the tire 180 on the rim will solve some problems due to cheap castings, valve stem weight, etc.

I’m still thinking bad tire though. Btw, OP, what’s the date code on the tires?

Huh...

Whenever changing tires you always remove all the weights. We also remove all remaining adhesive. Remove the old tire, check the rim for dents, bending, cracks and the sealing shoulder/lip. May need a quick brush if too much rubber residue from tires sticks to it as it may loose pressure. (These usually take a long time but you can add a psi every week or so.)

For sportscars I usually give the rim alone a quick spin on the balancing machine to check for runout and the machine is far quicker in telling me if something is wrong. Also one needs to know his balancing machine to get the rim properly centered.

If the first spin with the new tires gives more than 30 g (grams where 30 g approx. 1 ounce) I rotate the tire 180 degrees marking the initial spot of the correction on the rim and tire. From where the correction wanders to you can determine if the tire is the culprit.

Aluminium rims which make up about 90 percent of today's wheels never use the weights that attach with a bent metal tongue. You can damage the paint! The weights (correct is "masses") that are glued to the inside of the rim are those to be used with aluminium wheels. On the picture I do not like the look of those. They look "old" to me.

As it is OEM wheels they are usually very high quality and I have hardly ever seen a rim which was more than 5 - 10 g out of balance. (Only the rim by itself)
A good tire shop balances to +/- 1 g, while the Blazer is happy with about +/- 3 g. Above that you start to feel it at higher speeds. Above 15 g it starts to wobble and vibrate. Above 30 g you are not going faster than 35 mph for fear that something is shaking loose.

Really? I just bought these tires. They have less than 500 miles on them. Should I take this concern to Pepboys and ask them to investigate? Could new tires come damaged?

Does anyone know a chain shop that's really, really, really good with tires? If you all say that aluminum wheels shouldn't have/need weights on the outside, and that the OEM wheels don't need that much tuning, then there is something very wrong with the tires apparently, and I need to get an expert diagnosis. I've been to several Pep Boys locations around my area, and I'm not sure I can really trust their techs.

How would you know if the wheel is out of wack versus the tire? Would you balance test the wheel with no tire, then check it with the tire?

This is a Blazer I use as a long distance commuter (45 miles one way to my work place). I need to have good tires installed correctly.

A few observations, some of which have already been made:

Wheels can be out of round. They can be spun on the balancer and observed or even checked for runout with a dial indicator. You can jack up the truck on that corner and check the rim with a dial indicator with the tire on the rim or fix a reference at the outer edge and spin the wheel.

Tires can be out of round from the factory. Michelin and Yokahoma's are some that have a good reputation for being true, some other brands not so much. I always ask to see the runout on the balancing machine slowly rotated after the tire has been mounted. You would not believe how much hop you will see with some brand new tires on a good rim. Weights cannot fully balance a wheel/tire combo that is hopping really bad.

Blocky off road tires can need more weight than top shelf car touring tires.

If a wheel tire combination needs a lot of weight on the first spin up then yes you can "index" the tire on the wheel by rotating it 90 or 180 degrees and try again. Some tires have dots on them telling the tech where to start in reference to say the valve stem.

Usually on aluminum rims the weights are stuck on on the inside inner wheel surface. I don't know if some Al wheels these day are set up to accept pound on rim weights but I agree that it looks like a**.

Balancers can be out of spec. Techs can get the wheel on the spindle slightly off.

The best tire shops in my town are independent small outfits not chain shops. You can spot a better shop if it has older more experienced techs. Also look for someone who does road force balancing or tire truing. Ask them if they do tire indexing to minimize balance weights. A really good shop will do more of these things. Ask them which brands of tires routinely have out of round problems vs easier to balance brands and see if they sound like they know what they are talking about. Of the chain shops here, Tires Plus is the best.

Good luck, chasing tire issues can be a PITA for sure.

George

I've notice that I have to specifically ask for the sticker weights... they always try to give me the clip on... i hate them!!

any shop really i think it's just a way for them to save money? Lol

I called around some different places just trying to pick their brain. A resounding majority of the people I talked to said there's way too much weight on all 4 wheels.
On the rear passenger I counted the following weights: 1.75, 1.25, .75 on the outside, and 1.25, .75 on the inside. For just one wheel.
When the tech who did this balance returned the vehicle, I only saw the one outside weight on each of the driver side tires, so I didn't think much of it then.

Now really looking at this with you guys, I'm really wondering what the hell was this guy was thinking.

I didn't really know what sticky weights were until now. The rear passenger has sticky weights on the inner wheel that have always been there. When I got the new tires installed, the guy at the counter assured me they remove all the weights are start from scratch. Well, they seemed to have never removed those sticky weights. So this whole time I think they've been chasing that as the balance problem not knowing what it was.

I don't recall exactly when these sticky weights were put on. I just happened to notice them one day when I was cleaning and detailing the rims. Weirdly this is the only wheel that has them.

https://cimg7.ibsrv.net/gimg/blazerf...72af5479d0.png

So guys I have an official verdict.
The new tires are just bad.

I'm at another Pep Boys location I trust, and they're telling me the tires are bad. They let watch them work the balancing machine, and both front wheels are asking for 5 grams of weight. They also balanced just the wheel with the tire off, and the wheel itself balances out correctly. Seems I got a bad batch of tires.