Tire wear mystery

A

Adam Aulick

Newly bought 2001 Outback 5-speed, 125K miles.

I have a tire mystery.

When I bought it, the car had two like-new tires, and two mostly
finished tires with feathered sawtooth wear pattern and patchy flat
spots. (Goodyear Regatta 2, if anybody cares) The odd thing is that
the worn tires are on the LEFT side of the car, as opposed to the back
or front. In the first weekend I put 600 high-speed highway miles on
the car, and the front right tire is already starting to show the same
sawtooth wear, and rounded edges to the outside tread blocks like
somebody's been using the corners for erasers. Back right still looks
new. There is a slight vibration that I feel in the floorboards and
steering wheel at 50 mph, which becomes a strong vibration at 85 mph.
Going through a curve with any real steering effort in either direction,
the vibration in the steering wheel disappears. Car tracks straight.
Fuel economy for 600 all-highway miles mostly somewhere around 70 mph is
23 mpg, which seems low but I don't know if that's got anything to do
with the tires or just driving too fast. Since then I've been driving
slower and not feeling much vibration.

All of this seems a litle strange to me. Why are the tires on one side
dramatically more worn than the other? If the vibration in the steering
wheel goes away on curves, doesn't that indicate vibrations coming from
the back? Why am I seeing accelerated wear in the front?

If this makes sense to anybody, please let me know. I can't decide
whether to buy two new Regatta 2's while there's still enough tread on
the good tires for them all to match, or just leave it alone until the
most-worn tires are done, get four new (better) tires and four-wheel
alignment, and see if it all goes away.

~Adam
 
Adam said:
Newly bought 2001 Outback 5-speed, 125K miles.

I have a tire mystery.

When I bought it, the car had two like-new tires, and two mostly
finished tires with feathered sawtooth wear pattern and patchy flat
spots. (Goodyear Regatta 2, if anybody cares) The odd thing is that
the worn tires are on the LEFT side of the car, as opposed to the back
or front. In the first weekend I put 600 high-speed highway miles on
the car, and the front right tire is already starting to show the same
sawtooth wear, and rounded edges to the outside tread blocks like
somebody's been using the corners for erasers. Back right still looks
new. There is a slight vibration that I feel in the floorboards and
steering wheel at 50 mph, which becomes a strong vibration at 85 mph.
Going through a curve with any real steering effort in either direction,
the vibration in the steering wheel disappears. Car tracks straight.
Fuel economy for 600 all-highway miles mostly somewhere around 70 mph is
23 mpg, which seems low but I don't know if that's got anything to do
with the tires or just driving too fast. Since then I've been driving
slower and not feeling much vibration.

All of this seems a litle strange to me. Why are the tires on one side
dramatically more worn than the other? If the vibration in the steering
wheel goes away on curves, doesn't that indicate vibrations coming from
the back? Why am I seeing accelerated wear in the front?

If this makes sense to anybody, please let me know. I can't decide
whether to buy two new Regatta 2's while there's still enough tread on
the good tires for them all to match, or just leave it alone until the
most-worn tires are done, get four new (better) tires and four-wheel
alignment, and see if it all goes away.

~Adam

Its gonna be moderately critical on AWD cars like Soobs to keep all 4
tires the same model AND very near each other in total wear.
Often, vibration is tire/wheel related and older tires may have some
bubble/tire seperation beginning.
A car may begin 'cupping' or have other odd tire wear if shocks are
failing or a wheel is out of balance as resonant 'bouncing' can occur.
Its POSSIBLE someone put the the worn tires on one side to try to
decrease strain on the center diff since tire wear was uneven.
I'd expect getting 4 new tires, with a good wheel inspection/balancing -
coupled with a good wheel alignment, to alleviate most of the problems
you mention. Also, try to inflate the tires to at least the manual or
'door' specs - most folks prefer to add 2-3-4 lbs above those pressures.

Carl
 
Adam said:
Newly bought 2001 Outback 5-speed, 125K miles.

I have a tire mystery.

When I bought it, the car had two like-new tires, and two mostly
finished tires with feathered sawtooth wear pattern and patchy flat
spots. (Goodyear Regatta 2, if anybody cares) The odd thing is that
the worn tires are on the LEFT side of the car, as opposed to the back
or front. In the first weekend I put 600 high-speed highway miles on
the car, and the front right tire is already starting to show the same
sawtooth wear, and rounded edges to the outside tread blocks like
somebody's been using the corners for erasers. Back right still looks
new. There is a slight vibration that I feel in the floorboards and
steering wheel at 50 mph, which becomes a strong vibration at 85 mph.
Going through a curve with any real steering effort in either direction,
the vibration in the steering wheel disappears. Car tracks straight.
Fuel economy for 600 all-highway miles mostly somewhere around 70 mph is
23 mpg, which seems low but I don't know if that's got anything to do
with the tires or just driving too fast. Since then I've been driving
slower and not feeling much vibration.

All of this seems a litle strange to me. Why are the tires on one side
dramatically more worn than the other? If the vibration in the steering
wheel goes away on curves, doesn't that indicate vibrations coming from
the back? Why am I seeing accelerated wear in the front?

If this makes sense to anybody, please let me know. I can't decide
whether to buy two new Regatta 2's while there's still enough tread on
the good tires for them all to match, or just leave it alone until the
most-worn tires are done, get four new (better) tires and four-wheel
alignment, and see if it all goes away.

~Adam

You may also enjoy searching/posting questions related to your soob at
www.ultimatesubaru.org and www.nasioc.com .

Carl
 
Carl said:
A car may begin 'cupping' or have other odd tire wear if shocks are
failing or a wheel is out of balance as resonant 'bouncing' can occur.

This may seem like a stupid question, but how do you tell that your
shocks are failing on a Subaru? I'm used to driving a Windstar and a
1987 Chevrolet Celebrity, and the Outback, um, handles a little
differently. When I push down the bumper looking for bounce, it just
doesn't go anywhere, and on the road it handles so much tighter than the
sloppy jalopies I'm used to, that I'm afraid Outback "this is terrible"
might still seem really good to me.
Its POSSIBLE someone put the the worn tires on one side to try to
decrease strain on the center diff since tire wear was uneven.

If somebody did that, was it reasonable, or boneheaded? Sounds like the
sort of thing I would do...
I'd expect getting 4 new tires, with a good wheel inspection/balancing -
coupled with a good wheel alignment, to alleviate most of the problems
you mention. Also, try to inflate the tires to at least the manual or
'door' specs - most folks prefer to add 2-3-4 lbs above those pressures.

If I put it off until the bad tires finish wearing themselves out, am I
damaging the car?
 
Blame tires first. soobs are "loose as a goose" meaning quite forgiving in
that they want to stay aligned.Some Tires have a direction of rotation. Left
will not appear to be the same as the right if they are assymetrical in any
way over the miles.
tire whorehouses fail to mention it again and again. I would get a
different brand closer to oem.
If those are oem, get a different brand anyway.
I encountered this once years ago, and apparently have been very lucky
since then, not even paying attention to tread symmetry and driving for many
smooth miles.
4wd is special on any vehicle. Soobs aren't known for the cupping strange
wear like a u-jointed 1980 dodge ya know what I mean?
tires need to be good. go an extra weight rating and speed above oem. The
older soobs were damn near deadly in subarus underestimation of the weight
and speed rating necessary. I would not be surprised if they are still doing
that.
-Barry
 
Adam:

To begin with, were the worn out tires moved from their original location?

If they were, that could explain why only one side. On the other hand,
if they were not, a weird wear pattern on only one side of the vehicle
would lead me to believe that the car has a camber problem on that side.
Was the car banged sideways against the sidewalk/curb?

When you say that the right front tire is showing the same problem after
the 600 miles, I believe that you really need a 4 wheel alignment. Find
what are the angles your car requires and make sure the alignment is
left within those specs. I have found that some shops have different
specs for some vehicles than those recommened by the manufacturer. I
always go for the manufacturer's. You can do the wheel alignment even
before you replace the tires as long as there are not major diferences
between them.

As long as the depth of the tread is about the same, you should not have
any problem letting the 4 tires wear out before replacing them.

I recently had a similar problem with 2 Toyo Proxes TPT tires. In my
case, the rear tires had the center bead worn out normally but both
sides of each tire showed cupping, flat spots, etc, as if you had
stumped on the brake without having ABS (but remember that the center
bead does not have any defects). Inspection of the suspension,
alignment, brake system, wheel bearings etc found not problems at all.
Taking the tires to the tire dealer promted the guy to say that it was
either a strut or alignment problem. Sooo... I moved the tires to the
front and I am (well, the wife is) tolerating the noise until I need to
replace the 4 tires. By the way, these tires require higher pressure
than specified in the rear and lower pressure in the front as indicaded
but the groove depths.
 
It has been my experience tire wear you described is caused by worn
shocks/struts.
Running oddball size tires will eventually have you looking at a $1k
transmission repair bill. And the really painful thing is all the
problems that caused this repair bill will still need to be addressed.
 
AS said:
Adam:

To begin with, were the worn out tires moved from their original location?

If they were, that could explain why only one side. On the other hand,
if they were not, a weird wear pattern on only one side of the vehicle
would lead me to believe that the car has a camber problem on that side.
Was the car banged sideways against the sidewalk/curb?

I don't know anything about the past, but there's no damage evident in
wheel appearance or vehicle handling at any rate. If somebody did move
them, that makes the whole thing a lot less strange. Perhaps the tires
wore unevenly front/back, somebody got to the point where two tires were
no good and two almost no good, replaced the no good just to sell the
car, and swapped the others out to one side to avoid problems with the
center diff. That explanation just leaves me with some problem,
hopefully as mundane as alignment, causing patchy wear in front.
When you say that the right front tire is showing the same problem after
the 600 miles, I believe that you really need a 4 wheel alignment. Find
what are the angles your car requires and make sure the alignment is
left within those specs. I have found that some shops have different
specs for some vehicles than those recommened by the manufacturer. I
always go for the manufacturer's. You can do the wheel alignment even
before you replace the tires as long as there are not major diferences
between them.

You mean not major differences between the old tires and the new ones
I'll put on, or major difference between the tread wear on the
older/newer tires currently on the car? Either way the answer is
they're pretty different.
As long as the depth of the tread is about the same, you should not have
any problem letting the 4 tires wear out before replacing them.

It's not. The left side is worn down much more than the right. Sigh.
 
Adam said:
This may seem like a stupid question, but how do you tell that your
shocks are failing on a Subaru? I'm used to driving a Windstar and a
1987 Chevrolet Celebrity, and the Outback, um, handles a little
differently. When I push down the bumper looking for bounce, it just
doesn't go anywhere, and on the road it handles so much tighter than the
sloppy jalopies I'm used to, that I'm afraid Outback "this is terrible"
might still seem really good to me.

Not stupid - I also have never 'really' been able to spot bad shocks on
smallish cars. One of my daughter's had a Toy Camry that was VERY bouncy
when driven - blown shocks. Same with another Daughter's Maxima. But how
to tell when they are - um - on the way out? I dunno. maybe someone will
chime in. Offhand, if those 125K miles were 90% highway, you may be OK
for another 50-75K - who knows? If it's tight and not bouncy now, just
start saving for struts.
If somebody did that, was it reasonable, or boneheaded? Sounds like the
sort of thing I would do...

The THEORY is the open diffs on each axle will prevent the center diff
from responding to slippage. I wouldn't rely on it though.


If I put it off until the bad tires finish wearing themselves out, am I
damaging the car?

Do the car AND YOURSELF a favor - put good, SAFE tires on the car.
 
I had way too much tire wear on a pretty new Outback a year ago. A
dealer agreed and aligned them. Wouldn't speculate how it happened.
I happened to talk to someone else waiting for their car to be
serviced later at a different dealership and they said they had the
same problem. I asked that service manager what might be causing it
and he thought it could be the way cars are tied down on the transport
trucks when they are delivered.
 
I completely agree with you, my friend's brand new 01 pulling to one
side, cause, deformed tire. My wife's 03 brand new, pulling to one
side, cause alignment and deformed tire.
 
Adam said:
Newly bought 2001 Outback 5-speed, 125K miles.

I have a tire mystery.

Hi,

At that mileage, if the shocks (struts) are original, they'd be my first
target for eliminating the "cupping." As explained by others, your tires
are "bouncing" along the road, and after the wear begins, it tends to
accentuate this wear pattern.

Shock mfrs suggest replacement at 50k miles. My experience is like
others in that smaller cars don't always respond to the "driveway
bounce" test, but I've yet to have any go over 100k miles w/o being
"gone."

After that, suggest four matched tires, careful alignment, a couple of
PSI over door sticker, and careful observation for further problems. At
that mileage, it's not impossible other suspension bits may be worn,
especially if they've been trying to do the job the shocks should do!

Rick
 

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