After having the 64,000 Km service done at a local Toyota dealer, which
included a 4 tire rotation (front to back same side), there is now a steady
mild thumping sound which increases with speed. Having returned to the
Toyota shop, I mentioned that prior to the tire rotation, there was no
thumping noise. They said the noise is from the tires wearing differently in
their new location compared to their previous location and suggested the
noise would eventually disappear when the tires took on a new wear pattern.
The current tires are Michelin MXV4 Plus.
I am wondering if the Toyota explanation is accurate, or if I should have
something else done or checked.

On Sun, 1 Oct 2006 10:24:29 -0400, "Bob" <star7 (AT) NOSPAMbaystreet (DOT) ca>
graced this newsgroup with:


it probably is...to a certain extent.


A common problem with tires that haven't been rotated regularly is
cupping. Once you have tire cupping, you'll pretty much need to
replace the tires.

Also, if you don't routinely rotate the tires (every 3-5k miles),
you'll have uneven, premature tread wear and increased road noise.

It *sounds* like you may have waited too long to rotate your tires. If
that's the case, your best bet is just to replace them or get used to
the noise.

I sold tires for almost 2 yrs (22 yrs or so ago) and the dealer's
explanation sounds far-fetched to me.

Take your car to a reputable tire store (from your e-mail address extension,
you're in Canada and I don't know any tire dealers in Canada) and tell them
you want the tires (unless you're certain which tire is 'thumping' then have
them check the specific tire) checked for tread separation. If it is tread
separation then that should be considered a manufacturer's defect and, in
this case Michelin, should give you a pro-rated refund on the unused mileage
on that tire (64,000 km is 38,400 miles and the manufacturer's warranty
should be in excess of that; for example, let's say it's 80,000 km, then the
unused mileage is 16,000 km. Divide 16,000 km by 80,000 km and you get 20%
which is then multiplied by the cost of what you paid for the tire.
Michelin will either send you a check or you can probably take that 20% off
the cost of a new Michelin (or maybe another brand, but you should always
have the same tread pattern on the front and/or back). you have to make
sure that wherever you go, that that store sells Michelin tires because they
should have the Michelin form which will have to be filled out. Of course,
my advice is based on 22+-yr-old experiences and Michelin policy have
changed since then.

hope this helps!


"Bob" <star7 (AT) NOSPAMbaystreet (DOT) ca> wrote

"cupping" is caused by worn shocks or struts. you can visually inspect the
tires yourself -- looking at the tread, if there is 'cupping,' some of the
tread blocks will be worn down more than the others thus appearing darker in
color. you can also run your hand along the tread circumferentially and if
there is 'cupping,' you will feel 'dips' in the tread.


<amstaffs (AT) home (DOT) com> wrote

On Sun, 1 Oct 2006 11:26:01 -0400, "Mike Piacente"
<mpiacente (AT) adelphia (DOT) net> graced this newsgroup with:


Yup, it can also be caused by an imbalanced tire, faulty steering
system etc.

an improperly balanced tire will cause vibration over 25 mph in either the
steering column if it's a front tire(s) out of balance or a vibration in the
driver's seat if it's a rear tire(s) out of balance.

steering/front end (and with many cars over the past 20 years, the rear end
alignment) problems don't 'cause 'thumping' or 'cupping,' they will cause
the tread blocks to 'feather,' which is where one corner of each (sometimes
random tread blocks) tread block is actually raised up a little higher than
the other three corners. you can see this easily or feel them if you run
your hand circumferentially around the tread.

Now it's possible Bob calls the problem 'thumping' when it could be more of
a vibration. From my training, 'thumping' means something specific to me.
His best bet is to take it to a tire store and ask that the tires be checked
for tread separation (if indeed there is a 'thumping') then check them for
proper balance. If everything checks, then check the shocks and struts,
front-/rear-end alignment and parts, and steering box.

Any reputable tire store technicial worth his/her salt will road test the
car (with or without the customer riding with him/her) first to get an idea
what the problem may be.



<amstaffs (AT) home (DOT) com> wrote

Thanks fellows for your input, much appreciated. Guess my options are to go
to a good Michelin dealer and/or back to the Toyota service depot and speak
to someone higher up. Perhaps the mechanic has done something irregular.
Thing is, the tires made no extranious noise nor any vibration prior to the
tire rotation at the Toyota dealer. I have never run into a similar
situation in the past with any of my vehicles.
Inasmuch as all Lexus periodic services have been done as evidenced by the
dealer maintenance record book, it doesn't necessarily mean the tires were
rotated periodically. I purchased the car from a Lexus dealer as Lexus
certified 6/06.
Any other new car I have owned previously, tire rotation was done on a
timely basis.