From: jim beam on
On 08/02/2010 11:45 AM, hls wrote:
>
> "jim beam" <me(a)privacy.net> wrote in message news:FN-
>
>> tires don't do this on their own, only if there is an underlying cause.
>
> Apparently they do. This vehicle had nothing wrong with it.

if there was nothing wrong, the tires wouldn't cup. there is no
mechanism within ordinary tire rotation that supports that wear mode.


> Shocks were
> new and in good condition (Bilsteins),

if there's hop and bounce because of worn bushings [bilsteins cannot
compensate for that], then the tires will cup.


> alignment was good,

again, alignment can seem ok, but it's a static measurement. dynamic
loading puts different stresses on bushings, and worn bushings will
allow the loaded position of suspension members to be in a different
average location than any static alignment assumes.


> and no worn
> suspension parts.

that can't be actually true, even if you believe it to be - otherwise
you wouldn't be experiencing any problem.


> That is why I, at first did not rotate. I should have.

just covering the symptoms - doesn't address the cause.


>
>>> Took them back to the tire shop (Discount Tire,
>>> Lufkin, Texas) and they told me lack of rotation was causing this.
>>
>> masks the symptoms - doesn't address the cause.
>>
>
> There was no mechanical defect...before I took the vehicle for rotation.
> Discount
> Tire used their Torque Stix, and the rotors warped within a couple of
> weeks. Note
> that I had had no rotor problems before this happened.

for many vehicles, this "warping" is a wheel seating issue, not actual
deformation of the disk.

and "torque stix" are only good if the impulse of the driver is known.
think about it - they're torsionally flexible thus limit torque only for
a specific impulse. if the input impulse is different [say different
brand of driver], the output impulse is proportional, not fixed.


>
>
>>> Similar happened to our Avalon. Michelins got only 30,000. Replaced them
>>> with Kumho' s and am getting much better wear, but noticed at about
>>> 10000
>>> the ride was deteriorating, noisy, etc. Rotated and it is a-ok for now.
>>
>> tires with only 50% contact do indeed tend to be quieter!
>
> Im not sure what point you are trying to make. There would have been no
> significant
> contact difference between the Michelins and the Kumhos.

not all of a tire tread is on the ground, particularly when worn. the
individual blocks wear and if you look closely, you'll see they tend to
slope with a combination of rotation direction and dominant traction or
braking force. if you want to see this for yourself, rub chalk onto a
smooth surface like the shiny side of some high density particle board,
and roll the tire over it. you'll see how much of the rubber actually
touches the chalk. based on what you've said here, i think you'll be
surprised.

once that wear is established, moving that tire to another station means
that wear pattern keeps part of the rubber block off the ground. that
can easily be 50% of the contact area. thus you can get crazy numbers
like up to 50% less traction.


> Both were quiet
> at first.
> The Michelins were still quiet when they wore down to the wear bars.

michelin spend more on research than practically all the other tire
companies combined. if you want a quiet tire, they'll make a quiet
tire, even if you're rotating them.


>
> I do not expect the Kumhos to be as quiet as those particular Michelins,
> although
> they are very good tires. The Kumhos are a lot harder compound,should last
> a long time. Traction is good, but probably not as good as the much
> softer Michelins.
>
> Above, I should have said I rotated and had the tires rebalanced. They
> returned
> them to like new performance.

believe it or not, "new" performance can be less than those that have
worn in, particularly for dry surfaces. that's why tires typically have
labels warning you about braking excessively during the first few
hundred miles. it's also part of the reason why racers shave their tires.


>
> There is nothing wrong with the alignment or suspension on this Avalon
> either.

so you say, but what is the mileage? have you inspected the bushings
under load? how many curbs have you struck?


--
nomina rutrum rutrum
From: jim beam on
On 08/02/2010 02:27 PM, Clive wrote:
> In message <FN-dnQcGYqxhncrRnZ2dnUVZ_gKdnZ2d(a)speakeasy.net>, jim beam
> <me(a)privacy.net> writes
>> nomina rutrum rutrum
> I've just looked up your sig in a Latin dictionary.
> Nomina = Name
> Rutrum = Shovel, Spade or trowel. What does it mean when it's combined
> as it is?

call a spade a spade.

--
nomina rutrum rutrum
From: chuckcar on
MNRebecca <webbrl(a)morris.umn.edu> wrote in
news:a6d19c18-3941-46dc-8b35-e7ed0b2d1c9b(a)b4g2000pra.googlegroups.com:

> Been googling and talking to co-workers and can't find any kind of
> consensus. My 2004 Ford Taurus has just eaten through its second set
> of tires in 4 years. First set was relatively expensive (Triple
> Treads, experienced severe cupping and inner tread wear after 18
> months/30,000 miles). Second set was cheaper (Cientra Plus) and, at
> last rotation, I was informed that they are about shot (after about
> 36,000 miles). My driving conditions:
>
> -60 miles commute per day on paved country highways with no traffic or
> potholes, just two reductions in speed to pass through small towns
> along the way.
> -Northern plains state i.e. snow, ice, and melting solvents on roads.
> -Some potholes in parking lots at work but I try to avoid them.
>
> I don't peel out or brake excessively. Thoughts? Could it be my
> particular car (rather than Tauruses in general) eating the tires? I
> bought it used with about 20,000 miles on it. Thanks.

And your milage is? without knowing what sort of driving you actually
do, milage is the easiest way to measure that. I'm not saying you're
trying to break the record for Le Mans, but it surely is a determining
factor.



--
(setq (chuck nil) car(chuck) )
From: Hachiroku ハチロク on
On Mon, 02 Aug 2010 11:00:53 -0400, Scott Dorsey wrote:

> hls <hls(a)nospam.nix> wrote:
>>
>>Did you rotate these tires religiously? That is more important now than
>>ever before.
>
> Is it really? With modern tires being directional you can only swap them
> front and back when you rotate... does that really make that much of an
> improvement in equalizing wear?
>
> I have to admit to being lazy about rotating myself.

What does "rotate" mean???

I have NEVER rotated tires and get 60-80,000 miles per set!


>
>>Otherwise, like Scott said, get your car checked for alignment front and
>>back. You can eat up a set of tires before you know it if alignment is
>>poor. If you can find a really good frame shop, for example, they will
>>have equipment and experience that cheapo franchise alignment bays
>>wont have.
>
> Don't go to to the cheapo franchise places. A bad alignment is usually
> worse than none at all.
> --scott


We have a guy around here that is a MASTER! After he gets it lined up, he
does it AGAIN to set the wheel straight.


From: hls on

"Hachiroku ハチロク" <Trueno(a)e86.GTS> wrote in message news:dUI5o.47998
>
> What does "rotate" mean???
>
> I have NEVER rotated tires and get 60-80,000 miles per set!

Toyota, I am told, will not honor certain parts of their warrant if you
do not warranty according to their directions

If you dont want to rotate, and are happy with your tire life, good for
you.