Bad Tire Belt?

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The Critic

The Critic

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Earlier this week, I did a routine service on a TSX that included rotating the tires.

After rotating the tires and setting the tire pressure, I noticed that there would be a very noticeable vibration and wobble at speeds between 10-40 mph. The vibration/wobble goes away entirely at speeds about 40, and you only feel a slight rough ride at higher speeds.

Do note, that the vibration was not present prior to the tire rotation.

I have triple-checked the tightness of the lug nuts so I am fairly confident that is not the issue. When I took the tires off, I was not purposely inspecting the tires for signs of damage but I did not notice any obvious issues (i.e. bubbling, puncture, etc).

At first I suggested to the owner that the issue may be wheel balancing and advised her to take it back to Discount Tire. However, after some more thought, this seems more characteristic of a bad belt.

The tires are Yokohama YK520 on the RF, LR, RR and have about 50-60% remaining. The LF is a near-new YK580 that was recently installed.

Thoughts?
 
Does tyhe bad belt equate to a slight warp in the tyre? Well I'm calling it a warp, but it could be more like a slight "hop" if you will. I've been unfortunate enough to purchase tyres with said defects already (discovered on a balancing machine, by looking at the tyre rotating vertically).
 
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When I had a bad belt, it was only in a certain range of speeds, and they were higher, like 50-65MPH.

When it was on the front, I got a shake in the steering wheel. On the rear, it was not noticable.
 
I do not recall any visible defects in the tire, but then again, I was not actively looking for them either.

JHZR2, the vibration is very noticeable in the steering wheel between 10-40 mph.

Update: I had the owner of the TSX take the car back to America's Tire/Discount Tire Company, as this is where she purchased all four tires and had the replacement YK580 tire installed (per the certificate).

They told her that the vibration was caused by having different tires on the front axle, and they resolved the issue by rotating the tires on the front to the rear and rebalancing all four.

To clarify, this was the previous arrangement of tires:

L/F: Yokohama YK580, 90% remaining
R/F: Yokohama YK520, 60% remaining
L/R: Yokohama YK520, 60% remaining
R/R: Yokohama YK520, 60% remaining

After the service, this is the arrangement:

L/F: Yokohama YK520, 60% remaining
R/F: Yokohama YK520, 60% remaining
L/R: Yokohama YK580, 90% remaining
R/R: Yokohama YK520, 60% remaining

I will confirm the full details, but based on what I know so far, I am not impressed by their solution at all.
mad.gif
 
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Nope. That's just delaying the problem. Having different tread depths will cause a pull or a push. It will not cause a vibration. Especially when the tread difference is not too much. Also the vibration at speeds below 40 points more towards a bad tire. Their fix is a band aid. If you have access to a balance try seating the tire 180 degrees from its current position. See if that helps. If they road force is too high you won't feel the defect by hand but you will when you drive it. I'm assuming you checked for the obvious bent rim.

Their reasoning will lead to a solution of putting another new tire to even the tread depths out.
 
The Critic sent me a PM - and I responded off line.

But I did have a few things to add to THIS conversation. So I hope The Critic will forgive me for cutting and pasting parts of my response.

When we talk about runout and vibrations, we have to separate the lateral direction (side to side) from the radial direction (up and down)

Tire related vibrations are pretty much all about the radial direction - and they occur in the 50 to 70 mph range.

Why that speed range? Suspensions are - in engineering terms - spring/mass/damper systems. SMD systems will have a frequency where the system doesn't damp out cyclical input. This is called the resonant frequency. In cars, this is known as the "wheel hop frequency" - because the wheel will hop if subjected to input of that frequency - like when the road surface is uneven. Needless to say, for the road surface to cause an undamped vibration, the speed has to be right.

It turns out that a properly designed suspension will have a wheel hop frequency when the wheel end is rotating in the 50 mph to 70 mph range.

A vibration in the 10 to 40 mph range tends to be more wheel (as opposed to tire) - and it tends to be lateral runout, not radial runout. Vehicles are pretty insensitive to lateral inputs relative to tire manufacturing tolerances. This is not to say an odd tire doesn't leave the factory now and then, but it is extremely rare and usually evident right away - not when the tire is 60% worn.

BTW, this vehicle insensitivity to lateral input is the principle behind Hunter's "SmartWeight" system.

Is it possble that this is a belt leaving belt separation? Yes, but those also show up at the wheel hop frequency.

So I would tend to look for a wheel that has some lateral runout.

- and to isolate which assembly it is, I would move one of the front assemblies to the rear. If the vibration stays the same, it's the one that didn't move. Otherwise, it's the one that did.

And one other thought: At really low speeds, the suspension - for practical purposes - isn't doing it's thing. It tends to act more like a stiff beam.
 
Originally Posted By: The Critic

I will confirm the full details, but based on what I know so far, I am not impressed by their solution at all.
mad.gif



If it doesn't have an obvious broken belt, what are they supposed to do? Just start replacing tires?

If they missed an obvious broken belt, then that's something worth being angry about.
 
Originally Posted By: stephen9666
Originally Posted By: The Critic

I will confirm the full details, but based on what I know so far, I am not impressed by their solution at all.
mad.gif



If it doesn't have an obvious broken belt, what are they supposed to do? Just start replacing tires?

If they missed an obvious broken belt, then that's something worth being angry about.


I would have expected them to refer her to a location with a Hunter road force balancer or try moving one tire to the front at a time, as Capri had suggested.

I'll update this thread in a bit once I confirm all of the details.
 
So, I spoke to the owner. The shop basically told her that the mismatched tire was the source of the vibration, and that they are experiencing problems with this model tire. Their recommendation to her was to replacing the other 3 tires with new YK580s, at her expense of course, in order to resolve the problem.

I think a trip to a Hunter Road Force Balancer is in order, or at least more of a troubleshooting effort by the shop.

Perhaps I will get the shop to follow the method suggested by CapriRacer to isolate the problem. Thanks again, CapriRacer.
 
As usual, CapriRacer was correct - one of the rear wheels was severely bent.

Also, the Yokohama YK520 tires wore out in about 1/2 their advertised mileage, so DT replaced them with a generous pro-rate for a set of YK580s.
 
that was a known problem with the yk520's and one of the major improvements in the yk580.
 
Originally Posted By: CapriRacer
When we talk about runout and vibrations, we have to separate the lateral direction (side to side) from the radial direction (up and down)

Tire related vibrations are pretty much all about the radial direction - and they occur in the 50 to 70 mph range.


So, the steering wheel vibration that I've been fighing in my A6 would most likely be a radial direction problem? It comes on at 50 and stays up to about 75mph, and it makes the steering wheel oscilate and the front end shakes a bit. I would have thought that it would have been a lateral runout problem, based on the actions of the steering wheel.

This is a notorious problem on the C5 A6 and allroad chassis. It would be nice to be able to tell everyone on the forums what the root cause of the problem is. Some allroad owners have actually said the problem was solved with new front axles, though.
 
Originally Posted By: The Critic
Earlier this week, I did a routine service on a TSX that included rotating the tires.

After rotating the tires and setting the tire pressure, I noticed that there would be a very noticeable vibration and wobble at speeds between 10-40 mph. The vibration/wobble goes away entirely at speeds about 40, and you only feel a slight rough ride at higher speeds.

Do note, that the vibration was not present prior to the tire rotation.

Thoughts?



I rotated my tires for the 1st time last week on kitacamry and I worried in advance of just this...that what was fine before rotation would not be afterwards...I once had an eversoslightly bad wheel on an Altima causing a bit of rumble at 55 when it was up front....good thing I rarely did 55.

Fortunately all is okay...sigh of relief.
 
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