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Car Forum / Driving, Maintenance, Tuning / Maintenance and Repair / October 2006

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Replacing SUV tire(s)

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Walter Cohen - 02 Oct 2006 02:54 GMT
I had a flat tire on the front passenger side tire on my SUV.  My wife
didn't know about it and started driving, not realizing the tire was flat,
and a few minutes later came back and told me about it.  I'm not sure how
far she drove on a flat tire (never a good thing to do).  Anyway, I
temporarily put the spare donut tire on the car and took the wheel/tire to
Sears.

I told them to just fix the flat.  They said they couldn't because the tire
was damaged from driving while the tire was flat.  Ok, then I said replace
the tire with a new one.  He said that's fine but they could/will not mount
it for me because the car is 4WD and the tread depth on the one new tire
would be som much more/taller than the remaining 3 that it could damage the
gear box.  They are not authorized to put just one new tire on a 4WD
vehicle.  I then said, ok give me two new tires then and put them both on
the same axle.  Again they said no as they could not - for the same reason
about the gear box stuff.

So I eventually caved in (perhaps I should not have) and purchased 4 new
tires for the car.  I did not want to do that as about 18 months earlier I
had already purchased 2 new tures for the rear.  So $600 later, instead of
$125 later I have 4 new tires....

Does this sound right?  Did I waste my money buy having to put 4 new tires
on the car to have the same tiure tread depth to not damage the gear box?
I'm thinking of calling Sears and discussing and maybe complaining to them.
What is the deal on a 4WD car and tires with different tread depths?

Thanks,
Walter
Lawrence Glickman - 02 Oct 2006 03:14 GMT
>I had a flat tire on the front passenger side tire on my SUV.  My wife
>didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 25 lines]
>Thanks,
>Walter

My layman'e interpretation?

Think about this:
if the tire inflation ( and therefore the circumferance ) of each tire
is not exactly the same, what have you got?  You have been driving
around with *slightly* different tire pressures, and therefore
slightly different tire radii...no more or less than differing tread
depths, no?

IOW, you've been f.cked.

"layman's" interpretation, since I have no qualifications other than
having a working brain ( sometimes ).

Lg
lugnut - 02 Oct 2006 05:01 GMT
>I had a flat tire on the front passenger side tire on my SUV.  My wife
>didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 25 lines]
>Thanks,
>Walter

There are a few vehicles that a difference in size of any of
the tires will confuse the ABS system resulting in a bad
situation when braking.  Yours may or may not be one of them
but, it may be that the Sears shop has chosen not to go
there on any of them whether or not the vehicle is one that
can be compromised with unmatched tires.

Lugnut
MasterBlaster - 02 Oct 2006 11:40 GMT
> > They are not authorized to put just one new tire on a 4WD vehicle.

> it may be that the Sears shop has chosen not to go there on any of
> them whether or not the vehicle is one that can be compromised with
> unmatched tires.

That's the standard "cover your a.s" policy.  Everyone knows that whoever
touched the car last is responsible for anything that happens to it.

The transfer case could blow up next week, and who gets blamed, the
customer who drove on the undersized spare for who knows how long
("It was working fine when I brought it to the shop"), or the Sears store
that put on a slightly larger (new) tire?
lugnut - 02 Oct 2006 14:36 GMT
>> > They are not authorized to put just one new tire on a 4WD vehicle.
>
[quoted text clipped - 9 lines]
>("It was working fine when I brought it to the shop"), or the Sears store
>that put on a slightly larger (new) tire?

Unfortunately, too many people think the small donut spare
is for use until they have the next flat at which time they
will take care of it.  Meanwhile who knows whether or not
they know how to use their powertrain properly under what
conditions.  You are correct.  It is a CYA policy and I
don't know that I can blame them with today's litigation
climate.  I think the proper way to handle this would be to
have the info written on a work order releasing the vendor
from any liability for damage to the drivetrain if it comes
in with a mismatched tire if that is their problem. That
will not preclude thier ability to sue the vendor if it can
be shown that the failure and resulting damages were a
result of failure to complete the work with reasonable care
using standard industry practices. Let the customer decide
from there.  The fact is that you can have tire diameters
mismatched as much as you would get between tread depths
just because of inflation differences and, probably, over
half the vehicles on the road at any given time have
improperly inflated tires to one degree or another.

Lugnut
Don - 04 Oct 2006 04:22 GMT
>>I had a flat tire on the front passenger side tire on my SUV.  My wife
>>didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 34 lines]
>
>Lugnut

And since the original poster chose not to let us in on the make and
model, we don't know if the vehicle has some variant of full-time AWD
or has a transfer case that can totally disconnect the front and rear
differentials.  We don't even know if has ABS.

"SUV" could mean a 76 Suburban 4x4 or could mean a 2005 Subaru.
There ARE differences.  I once diagnosed a problem with a Honda Civic
4x4 where the center viscous drive differential howled continuously
due to different profile tires front and rear.  On the 76 Suburban
example it wouldn't make a rat's a.s.

Don
www.donsautomotive.com
Mike Romain - 02 Oct 2006 14:57 GMT
If your vehicle came with a 'silly spare', then you can normally put
slightly different tires on it and get away with it or at least change
two on the same axle and be safe.

If it came with a full sized spare, then you need to ask the
manufacturer or read the owners manual to see if you have a locked or
limited slip diff or a all time 4x4 that can be wrecked with a mis
match.

The don't 'normally' put donuts or 'silly spares' on vehicle that can be
destroyed that way.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos:  Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
(More Off Road album links at bottom of the view page)

> I had a flat tire on the front passenger side tire on my SUV.  My wife
> didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 25 lines]
> Thanks,
> Walter
phaeton - 02 Oct 2006 15:45 GMT
> If your vehicle came with a 'silly spare', then you can normally put
> slightly different tires on it and get away with it or at least change
> two on the same axle and be safe.

Don't most (or all) modern AWD or all-time-4WD vehicles have the 'third
diff' between the front diff and rear diff, thus resulting in:

1) Every wheel can turn at its own whimsical speed with no drivetrain
damage or funky handling.

2) A relative compromise to the "All Wheel Drive" concept under certain
conditions (but still better in say, snow/slush/heavy rain compared to
2WD if you don't do something stupid)

3) There is no 3.

4) Didn't Jeep 'pioneer' this sort of thing many many many many years
ago?

-phaeton
Mike Romain - 02 Oct 2006 16:19 GMT
> > If your vehicle came with a 'silly spare', then you can normally put
> > slightly different tires on it and get away with it or at least change
[quoted text clipped - 16 lines]
>
> -phaeton

Yes, Jeep called it a quadratrac I believe.  They now have a slectrac
that acts similar.

That is what I was implying with the use of a silly spare.

If you have a 'part time' 4x4 with a locking center diff or if you have
limited slip or a locker in the axle diffs, or some ABS systems you need
to match the tires, otherwise....

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos:  Non members can still view!
Jan/06 http://www.imagestation.com/album/pictures.html?id=2115147590
(More Off Road album links at bottom of the view page)
ray - 02 Oct 2006 15:37 GMT
> I had a flat tire on the front passenger side tire on my SUV.  My wife
> didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 12 lines]
> the same axle.  Again they said no as they could not - for the same reason
> about the gear box stuff.

driving with a 44" tall tire and a 30" tall tire IS hard on the diff.
but, driving with a 30" and a 30.1" tall tire isn't exactly tearing up
anything... measure your new tires, I bet the circumference isn't the same.

If anything tho, you want the tires on an axle to be roughly the same
for grip - think of stopping in the snow with one bald tire and one snow
tire.

I would have had them change one pair of tires so they were the same and
then kept the old tire as a spare.

No need to get 4 tires.

And yes, this was a CYA policy by them.

I've had non-stock sized tires mounted on my truck by mentioning upfront
 that I knew they were nonstock and they wrote that on the work order
and then mounted them without any grief.

Ray
C. E. White - 02 Oct 2006 15:57 GMT
> And yes, this was a CYA policy by them.
>
> I've had non-stock sized tires mounted on my truck by mentioning upfront
> that I knew they were nonstock and they wrote that on the work order and
> then mounted them without any grief.

I like to by tires at Sam's Club (decent price, decent workers mounting the
tires, no attempt to sell me shocks, brakes, a new air freshener, etc.).
Unfortunately they have adopted a very strict policy on replacement tires.
They will only sell you tires that are the same size, type, and rating as
tires that the vehicle manufacturer offered on the vehicle. This was a pain
in the rear when I needed new tires for my Saturn Vue. They had nothing in
the OEM size at all. When I suggested that a slightly larger tire was just
fine, they said, nope, it is not in the book. They wouldn't even let me sign
a statement saying I understood there were not liable because of the
non-standard size. My Vue didn't even have ABS, so any arguments about the
tire size screwing up the ABS did not apply. You can circumvent this by
taking in the rims (without the car), but that is a pain as well and
eliminates the free rotation and balancing you normally get.

Ed
ray - 02 Oct 2006 18:39 GMT
>> And yes, this was a CYA policy by them.
>>
[quoted text clipped - 17 lines]
>
> Ed

I've ran into that as well, which is why I was surprised that it was
Canadian Tire that did it for me without all the extras.  And they've
done it twice in two years - once for my Jimmy, once for my pickup.
Although, I wish they would have pulled the drums on my pickup... it
wasn't until months later I discovered the nasty oil seal leakage... I
might have even let them fix it.
Oh well, normally people complain about mechanics being pushy...

Ray
(fwiw, stock tires for the Jimmy 205/75-15 -> replacement tires I chose
were 235/75-15 which were stock size for the later ones.  The pickup
went from a 245/75-16 to a 265/75-16 which was also a stock size, just
the largest stock size.)
phaeton - 02 Oct 2006 16:06 GMT
> And yes, this was a CYA policy by them.
>
[quoted text clipped - 3 lines]
>
> Ray

Some places STILL won't do that though.  You tell them "yes I know what
I'm doing, yes I understand the 'risks', and yes I understand that you
don't want to be liable.  Write it on the work order, I'll sign it, and
you will be 100% free and clear if I go out and kill a school bus full
of kids"....

But they just won't do it.  I dunno.   Maybe it's because in this
'litigatious climate' the lawyers have found ways around that.  I know
that in some states you legally cannot put rotors and drums back on the
car if they're under spec (too thin, that is).  That's got to be a hard
sell to the customer sometimes..."yes we turned them.  But now they're
too thin and I can't put them back on."

But the fact is, all the bitching and moaning by the customer and all
the signed documents won't save you- you get a hefty fine whether they
crash and die or whether they come back in at the end of the week and
have you do it right.

-phaeton
ray - 02 Oct 2006 18:42 GMT
>> And yes, this was a CYA policy by them.
>>
[quoted text clipped - 23 lines]
>
> -phaeton

I know.  Which is why I own a pickup truck for delivering wheels and
tires to be mounted for my race car with a minimum of fuss by the tire
store.

And it's also why I patronize certain places and don't go back to places
that don't work for me.

That said, I understand why some places won't install non-stock tires,
especially undersized tires, because people are cheap.  I've seen quite
a few pickups with 3000 pounds of bricks in the back and what looks like
10 year old 205/75-15's with 10 psi in them squirming down the highway.
Wally - 02 Oct 2006 21:03 GMT
Ok, I went back to day and spent an hour there "speaking" with the
on-duty assistant manager as well as the auto center manager.
Originally the assistant said it was my fault, that I could have, at
the time, just declined everything and chose not to have anything done.
Well as I was there to get a flat fixed that was not my intention,
although I suppose I could have.

What I really liked was when he said that if I bring the car back with
the 4 new tires (wife has the car now) then he would gladly replace all
4 tires with my 4 old tires and refund my money.  He still had my 4 old
tires as they had not been picked up for recycling yet.  Actually he'd
put the donut back on where the flat was.  He was actually serious when
he said that but I said that it was an unacceptable solution and was
quite surprised Sears would do such a thing.

They then said that it was Sears policy for all 4WD cars to not mount
new tires if you don't purchase all 4 of them new from Sears.  When I
asked to see this in writing they flipped through there 'Ops and RMDS"
binder and could not find anything.  I pointed out that there is
nothing prominently displayed in the area that a customer could see
that this was supposedly their policy.  After a few minutes they said
they remember seeing something to the effect about the 'policy' on
their intranet.  Again I said, I as a customer have no access to Sears
intranet and it wouldn't matter anyway - it should be displayed on a
wall somewhere so that a customer can see/read it and not just take it
at face value from a Sears technician.  They were unable to produce
this mystery document from their intranet.
The Auto Center Manager did agree that it should be clearly available
for a customer to see and read (I'm surprised he even agreed about
this).

In any event, I called my local Mercedes repair center and asked them
about the 4WD issue and what they do/recommend when only 1 tire is bad.
He said that they recommend replacing tires in pairs on the same axle.
Which is what I offered to Sears yesterday and they declined to do
that.

The Auto Center Manager took me aside and said that if I show him the
owners manual or he can chat with the MB technician about replacing
tires in pairs (and not all 4) then he really owes me some money.  At
this point it sounds like he would refund the two tires (and associated
balancing and disposal fees) and still let me keep the tires.

Walter

> > I had a flat tire on the front passenger side tire on my SUV.  My wife
> > didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 33 lines]
>
> Ray
* - 02 Oct 2006 22:03 GMT
Wally <w_cohen@hotmail.com> wrote in article
<1159819405.863810.114440@i3g2000cwc.googlegroups.com>...

> What I really liked was when he said that if I bring the car back with
> the 4 new tires (wife has the car now) then he would gladly replace all
> 4 tires with my 4 old tires and refund my money.  He still had my 4 old
> tires as they had not been picked up for recycling yet.  

TRANSLATION: No one had come in looking to buy used tires of that
particular size yet!
Lawrence Glickman - 02 Oct 2006 22:04 GMT
>The Auto Center Manager took me aside and said that if I show him the
>owners manual or he can chat with the MB technician about replacing
>tires in pairs (and not all 4) then he really owes me some money.  At
>this point it sounds like he would refund the two tires (and associated
>balancing and disposal fees) and still let me keep the tires.

Sears has gone into Damage Control Mode.

IOW, you still haven't a dollar to buy a cup of coffee with, do you?
No...I didn't think so.

What you want is 2 new tires on the axle that had the original
defective tire, and your *original* tires back on the other axle.

And, a refund of the difference in price between the 4 tires they
shoved down your throat, and the 2 you should have gotten to begin
with.

Lg
Wally - 02 Oct 2006 22:23 GMT
Yes, that is what I want - or even to keep the new tires and still get
the refund, as the service manager implied :)

By the way, the new tires have a tread depth, according to the sales
receipt, of 11.  What does 11 translate to in inches?

Thanks,
Walter

> >The Auto Center Manager took me aside and said that if I show him the
> >owners manual or he can chat with the MB technician about replacing
[quoted text clipped - 15 lines]
>
> Lg
Lawrence Glickman - 02 Oct 2006 22:27 GMT
>Yes, that is what I want - or even to keep the new tires and still get
>the refund, as the service manager implied :)

Watch what they do, not what they say.  Believe it when you see it.
Maybe he is trying to buy his way out of trouble.  Maybe he knows he
screwed the pooch, and is going to give you a deal to keep his head
off the corporate chopping block.  Anyhow, don't spend your money
until you have it in your hands.

>By the way, the new tires have a tread depth, according to the sales
>receipt, of 11.  What does 11 translate to in inches?
>
>Thanks,
>Walter

I dunno.  Not a tire man myself.  somebody here knows though, you can
bet your life on it.

Lg
Wally - 02 Oct 2006 23:46 GMT
Unless 11 means 11/32?

Walter

> >Yes, that is what I want - or even to keep the new tires and still get
> >the refund, as the service manager implied :)
[quoted text clipped - 15 lines]
>
> Lg
Lawrence Glickman - 03 Oct 2006 03:01 GMT
>Unless 11 means 11/32?
>
>Walter

Can't say for sure.  You can call any tire shop in the phone book
though.  That's what I would do.  Somebody there should be able to
give you the _correct_ answer.

Lg
Larry Harvilla - 04 Oct 2006 09:56 GMT
> Unless 11 means 11/32?

Yes, the "11" refers to 11/32" tread depth.

Signature

Larry Harvilla
e-mail: roads AT phatpage DOT org
blog-aliciousness: http://www.phatpage.org/news/

also visit: http://www.phatpage.org/highways.html
(in progress)

Walter Cohen - 06 Oct 2006 02:34 GMT
Final resolution:

I checked with MB headquarters and they have no written policy on this
issue.  They only "suggest" you replace the front tires in pairs if you are
replacing one because of damage or flat.  My MB owners manual also has this
"suggestion".  So I went back to Sears and told him what MB said and showed
him the owners manual.  He refunded half on my monies paid and still let me
keep the 4 new tires.  Not bad.

It pays to complain to people who can genuinely help.

Thanks to all for listening.
Walter

>>Yes, that is what I want - or even to keep the new tires and still get
>>the refund, as the service manager implied :)
[quoted text clipped - 15 lines]
>
> Lg
Lawrence Glickman - 06 Oct 2006 03:09 GMT
>Final resolution:
>
[quoted text clipped - 9 lines]
>Thanks to all for listening.
>Walter

Outstanding, Walter.  I'm happy this worked out for you the way it
did.

Lg
ray - 02 Oct 2006 23:27 GMT
> Yes, that is what I want - or even to keep the new tires and still get
> the refund, as the service manager implied :)
>
> By the way, the new tires have a tread depth, according to the sales
> receipt, of 11.  What does 11 translate to in inches?

I believe that would be 11/32" tread depth.

Ray
ray - 02 Oct 2006 23:26 GMT
> The Auto Center Manager took me aside and said that if I show him the
> owners manual or he can chat with the MB technician about replacing
[quoted text clipped - 3 lines]
>
> Walter

Wow.  If he's serious, I'd probably take him up on it right until he was
ready to hand over the cash and then I'd thank him for doing the right
thing and just sell my old tires in the buy & sell.

Ray
C. E. White - 02 Oct 2006 15:48 GMT
>I had a flat tire on the front passenger side tire on my SUV.  My wife
> didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 29 lines]
> Thanks,
> Walter

What was your vehicle? What size was your doughnut tire? If driving around
with different size tires was likely to damage the 4WD system, then the
vehicle manufacturer would have included a spare with the same OD.

There is an interesting thing about radial tires that comes in to play. The
OD of the tire has only a secondary affect on the rolling radius (the
dimension that affect the number of revolutions per mile). The tread
sections act more like a tank tread than the outside diameter of a solid
wheel. The actual rolling radius is mostly dependent on the radius of the
steel belt instead of the outside diameter of the tread. For instance, a
Michelin CrossTerrain P235R16 Tire has an outside diameter of 29". If this
was a hard wheel with a 29" diameter, it would take 695.4 revolutions of the
wheel to go one mile. According to the Michelin specs, the actual number of
revolutions per mile is 720 (at 45 mph - speed is a factor because it
changes the tire diameter slightly). 720 revolutions per mile gives you an
effective diameter of 28". This is close to the diameter of the steel belt
inside the rubber. This diameter of the steel belt is not effected by
wearing the tread down. There is some slight change in rolling diameter as
the tread is worn away, but not to the extent the outside diameter change
would indicate. In the case of the Michelin P235R16 tires, the tread depth,
was 10/32. Even if the effective rolling diameter was decreased from 29" to
28.4" (new to bald), the theoretical number of revolutions per mile would
have only changed from 695.4 to 710.1. Any system that can't handle 15
revolutions in a mile is already defective. Going around corners is a more
significant difference than that. And in actual fact the difference in
effective rolling diameter between the new tire and the old tire (assuming
the same brand, size, and type) was probably more like 5 revolutions per
mile and probably less.

I think it was justifiable to replace two tires (the bad one and the other
one on the same axle). Replacing four was totally unnecessary. And didn't
warning bells go off when this tire store forced you to buy four tires since
18 months earlier you had already just replaced two of the four?

Ed
ray - 02 Oct 2006 18:34 GMT
> There is an interesting thing about radial tires that comes in to play. The
> OD of the tire has only a secondary affect on the rolling radius (the
[quoted text clipped - 20 lines]
> the same brand, size, and type) was probably more like 5 revolutions per
> mile and probably less.

also, the width of the rim affects the shape of the mounted tire as well.
I have a pair 235/60R-15 BFG mounted on a 7" wheel and on an 8" wheel
for my race car.  You can see the difference - the tire on the 8" wheel
is shorter and wider even though unmounted they're the same.

Hmm... that just gave me an idea for stagger for next year...
* - 02 Oct 2006 16:03 GMT
Walter Cohen <w_cohen@hotmail.com> wrote in article
<cj_Tg.79$0d3.58@newsfe11.lga>...
> I had a flat tire on the front passenger side tire on my SUV.  My wife
> didn't know about it and started driving, not realizing the tire was flat,
[quoted text clipped - 25 lines]
> Thanks,
> Walter

Yet another example of the contributions that lawyers have made to
society.....paranoia in being the one sued for an accident.

Of course, the reknowned, proven, unethical Sears Automotive sales
strategies probably played a major role also.....as much or more than the
legal concerns.

Would it surprise you to hear that the tire industry is often the major
thrust behind such law-making that makes it easier to sell more-than-one
tire, and to sell up to the "correct" tire for the vehicle?

Think about it for a second.....

Was the "space-saver" spare exactly the same size as the original tire?

Did you notice any really bothersome unequal handling/braking
characteristics while driving on the "space-saver"?

Do you really believe the OEM would provide a "space-saver" if it could
possibly lead to litigation due to unequal tire sizing causing an accident
or causing damage to the vehicle?

Would a brand-new, full-tread tire have MORE or LESS size difference from
the other tires than the "space-saver"?

What happens to people who do not rotate their tires religiously? Does the
unequal wear create problems with handling and braking?....or differential
component wear?

Would you expect the ABS to malfunction while turning - when, even with
perfectly matched tires, the outside wheel is moving measurably faster than
the inside wheel?

We run stock automotive rear axles ( 1978-1985 GM 108" "Metric" chassis)
with different-sized ( one-to-four-inch difference in circumference) left
and right tires on the oval track - under full speed and pressure. The cars
often reach 100+ mph going down the straights -  with the smaller,
left-side wheel spinning faster than the larger right-side wheel traveling
down the straights.

Other than losing the lubricant, I have yet to burn out a set of spider
(differential) gears in 40+ years of racing.

I would be more concerned with the SUV owner who, under pressure from the
Sears monkeys, decides to put on less-expensive passenger car tires in
place of the LT tires originally supplied.....HE's the guy who's more
likely to play "turtle" in an emergency maneuver.

To beat the current "I cannot LEGALLY mount that tire...." B.S., you can
buy the tire, go home and take the wheel off the vehicle, then take the
wheel and tire to a place that mounts tires.

Most will not question what it is going on - if for no other reason than to
be able to invoke the, "I didn't know what it was being used for, I was
just asked to mount and balance it...." defense.

It's a pain in the a.s, but the only way around the people who are
determined to save us from ourselves.
C. E. White - 02 Oct 2006 16:15 GMT
> I would be more concerned with the SUV owner who, under pressure from the
> Sears monkeys, decides to put on less-expensive passenger car tires in
> place of the LT tires originally supplied.....HE's the guy who's more
> likely to play "turtle" in an emergency maneuver.

Most SUV and many light duty trucks (F150, Tundra, etc) come form the
factory with P series tires (often with extra load P series tires). There is
nothing wrong with using P series tires on trucks and SUVs as long as 1) you
de-rate the load rating by 10%, and 2) understand that the tires cannot
standup to off-road hazards as well as LT tires. In may cases the P Series
tires are a better choice for SUVs than LT tires because the sidewall are
not as heavy and do not build up as much heat at high speed as LT tires. For
a given load rating, an LT tire requires a significantly higher pressure to
prevent flexing and heat build up. The higher pressure and the stiffer
sidewall can make for a very stiff ride with no improvement in safety. Now
if you are going to spend a lot of time on gravel roads, or off roading, the
heavier carcass of an LT tire can be a real advantage. However, if you go to
a tire store with a strict policy of replacing tires only with the OEM size
and type, they cannot sell you LT tires for many SUVs. And if they do sell
you an LT tire for vehicle that came with P Series tires, they need to tell
you to adjust your inflation pressures upwards by 3 or more psi to prevent
heat build-up. How many tire monkies know to do that? Many of them either
over inflate the tires by blindly assuming the max pressure listed on the
tire's sidewall is the correct pressure, or they apply the P series pressure
on the vehicle's decal to the LT tires - also a bad idea.

Ed
* - 02 Oct 2006 18:20 GMT
C. E. White <cewhite3@removemindspring.com> wrote in article
<45212d8c$1@kcnews01>...

It has nothing to do with load rating....

LT tire tread design is a more open, aggressive tread.

It has less sidebite than the standard passenger car tire.

When I say "SUV" I mean Bronco, Blazer, RAM, etc., built on pickup truck
chassis.......NOT the little four-wheel-drive station wagons built on
passenger car chassis.

When the high CoG SUV or pickup gets around sideways, the open "LT" tire
tread will slide much more easily than the passenger car "P" tread will -
allowing the SUV to slide sideways instead of having the tire grab hold of
the road and have the high CoG tip the vehicle over.

On a "real" SUV, there really IS a difference between the "P" tire and the
"LT" tire.......
 
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