What does this tire noise mean?

I just bought a used car and the tire(s) make a noise I’ve not heard before. As I’m driving it/they make a constant wuh-wuh-wuh-wuh-wuh-wuh sound that increases and decreases speed as the car does.

Does that mean they need to be rotated or could they be out of balance?

Thanks!

That type of noise can be indicative of a slipped belt in one or more of your tires.
I would suggest having those tires checked by a reputable tire dealer, as this can be a safety hazard.

Sounds like the outer edges of the tires are “Feathered” (high-low-high-low) between the outer edges of the treads. Placing a straight edge ruler along that edge should be obvious if it’s that severe.

This can be from lack of proper rotation or severe worn bushings in the suspension. (rare)
But some cars like my 300ZX Twin Turbo and some other high performance cars have
uni-directional tires which can’t be Rotated because the manufactured tread pattern.

An “Out of Balance” problem would usually make the Steering Wheel shudder/vibrate at higher speeds.
A Engine Belt slipping is more of a “screeeching” noise and usually only is noticeable during starting and acceleration, not consistent speed.

Ooh, I hadn’t thought about them maybe having a problem internally. Thanks for the info. =)

The folks I bought it from have been fanatical about maintenance, I can’t imagine they’d ignore the tires but I’ll ask them.

Ah, the Z cars. I’ve always loved them! I once helped a buddy change a heater core in an old 260 - never again haha!

“A Engine Belt slipping is more of a “screeeching” noise and usually only is noticeable during starting and acceleration, not consistent speed.”

Of course, you are correct, but I was referring to a belt in the tire, not an engine drive belt.
I would have thought that the reference to “having the tires checked by a reputable tire dealer” would have been a clue to the type of belt to which I was referring, but…I guess not.

Shortly, I will correct the wording of my earlier post, so that it is less confusing.

The Belts can “slip” inside the Vulcanized layers of a Tire ?
You learn something new every day.

Yes, they certainly can. It’s happened to me, and the manufacturer replaced the tire. They would balance it, and I’d be back in a week or so, and they’d balance it again. After 3 balance attempts, and my assurance I hadn’t hit anything (along with a thorough inspection of the tire itself), they replaced it, the problem went away, and so did I.

Bad tires or bad wheel bearing could produce this noise.

Most likely a bad tire(s). You can run your hand over the tread of all 4 tires, if you feel cupping (like waves in the tread) then that tire is bad. No amount of balancing will fix a cupped tire, it has to be replaced or you learn to live with the noise.

First, let me say that a “slipped belt” in a tire is a physical impossibility. The term is used by folks who don’t understand tires very well in an effort to explain why certain things that happen. Unfortunately, it leads to mis-diagnoses.

In this case, it is likely that the noise is the result of irregular tire wear - which is usually caused by a mis-alignment condition. Fixing the alignment only addresses the cause, but doesn’t do anything about the symptom.- the irregular wear (and the noise ) is still there. While it is possible that fixing the alignment may cause the tires to wear off the noise generating wear pattern, it is more likely that the noise will not improve very quickly and not enough to be effective.

So I suggest that the OP get an alignment and consider replacing the tires.

For mine, it was a manufacturing fault. That was what they called it, anyway. I had the alignment done at the same time, and it handled very well, drove true, but after less than a week, started “thumping” and the steering wheel started vibrating. Went through the whole balance, drive, thump and vibrate cycle three times, until they replaced the tire (and didn’t mess with the alignment).

So what was it then? It wasn’t the alignment, bearings, brakes, etc. This was all on a set of brand new tires, btw.

Capri, I don’t doubt you, but what was it? I’d rather know what it was so I can be correct from here out.

CapriRacer, so if a “slipped belt” - or internal issue with the tire’s structure is impossible what does cause tire issues with unworn tires (such as new) or with tires that have no measurable wear issues? I’ve had both kinds of issues - a brand new tire that pulled no matter where it was put & tires that somewhat suddenly develop odd behavior also without measurable uneven wear. There’s got to be something besides uneven wear - no?

Maybe Capri would be happier if we called it “tread separation”.

I think that circuitsmith nailed it.
What I–and some others–refer to as a slipped belt, is probably more properly called tread separation.

The term “Slipped Belt” implies that a tire’s belt was in one position and moved to another position. I hope I don’t have to explain why that simply isn’t possible.

The 2 most common usages for the term are:

  1. For a tread separation – and while a misplaced belt COULD result in a tread separation, tread separations are very rarely caused by a misplaced belt – so one can’t use the term unless one has X-ray vision.

  2. For the cause of irregular wear – and misplaced belts rarely cause irregular wear. Irregular wear is usually caused by mis-alignment. Again, X ray vision is required here.

Chaissos asked “……but what was it? I’d rather know what it was so I can be correct from here out……”

Not enough information. If it was a tread separation, with a few rare exceptions, these take thousands of miles to develop.

Cigroller asked “…… so if a “slipped belt” - or internal issue with the tire’s structure is impossible what does cause tire issues with unworn tires (such as new) or with tires that have no measurable wear issues?..”

As I explained above, the term applies to a specific condition. If we expand the term to include a mis-placed belt, then a pull could be caused by that – but the use of that term is rarely applied to that situation.

But, cig, not enough information. What was the issue that developed suddenly? A pull would be there from the git-go.

There are a lot of things that can happen, only some of which are caused by the internal structure of the tire – and typically, these don’t appear suddenly. Even tread separations develop over time – typically thousands of miles to start and they grow from a barely perceptible vibration to a pronounced one over hundreds of miles.

There are a lot of terms that are commonly used in the retail end tire business that don’t quite fit - which is why the manufacturing and design end of the business never uses those terms. This one is particularly onerous as it applies to something that can not be seen without cutting the tire apart.

Obviously, I can’t speak for Cig, but for me…

  • Brand new tires. Had a 4 wheel alignment done at the same time.
  • Handled beautifully after that, drive straight and true, no pulling, nothing strange.

About a week later (somewhere around 200 miles), started thumping, vibrating. This developed slowly, over a few days and just progressively got worse. I could feel it in the steering wheel and rear end. They said I must have knocked a weight off, so they balanced it.

This whole procedure continued, and they eventually replaced the tire. I had the chance to look at the old one, and there was no cupping (that I could see), and the interior looked good.

That’s all the information I have for you. They said they’d send the tire back to manufacturer for analysis. This was all on an old Bronco, the heavy one, if it matters (which it shouldn’t).

/sigh

Yes chaissos - stuff like that. Tires can obviously be defective when new & I get the mis-placed belt & thanks for that. But they also occasionally go wacky for no apparent reason. I’m not challenging, either, capriracer. I happen to know that you are the primo tire expert up here. I’m just curious.

I have have heard the same noise from feathered tire edges after delayed tire rotation on front drive cars. Even after rotation the noise can persist and is not a safety issue in my experience. With two different cars with relatively narrow tires the noise would correct itself with a few thousand miles of driving but with wider tires on a newer front driver it would not. I have learned from this to not be lazy about tire rotation as the consequences can be either tolerating the noise or buying new tires.

Bottom line:

  1. tires are the most common source of that type of sound, either due to irregular wear or internal defects or damage.

  2. defects are intrinsic to a tire and can be verified on a road Force Balancing machine.

  3. irregular wear is a symptom, not a cause. It can be due to alignment, component wear, damage, or poor balancing. Any mechanic can determine which is the most likely and help get the problem corrected.

And, in summary, yes, you need to get this looking into. You may just have a badly balanced tire, but you could also have a dangerously worn ball joint. There’s no way to know without looking at the tire and under the car.

I appreciate it everyone, I’m going to swing by my local tire place tomorrow and see what they think. I haven’t felt vibration or anything in the steering so I’m hoping it’s one of the rear tires in case it does give out.

Thanks again!