Should I get 2 or 4 new tires?

[skibum]

Hi all--

I've reviewed some of the threads but I'd like to revisit a tire topic.
Bear with me if this seems like a long post:

- I have -- and love-- my 99 MT Subaru Forester S. I replaced the stock
tires with 4 Kelly Navigator Golds ~50,000mi and I have ~77,000 miles
on the car now.

'bout 3 months ago I struck a rock on the highway, which tore the
sidewall of a front tire and dinged its wheel to the point that they
both needed to be replaced. The local tire dealer recommended 2 new
tires (same Kelly's), which I bought and had them mounted to the front
axle.

More recently I've noticed that there's a "clunking" noise/sensation
from the front wheel wells (you can feel it in the steering wheel/stick
shift), only when I'm slowly turning the car with my steering wheel
turned to the extreme right or left. The feeling's only intermittent
and fortunately's not present with regular driving and turning at
intersections.

I brought my Subie in for an inspection and they recommended I buy 2
new tires first, before they try to do a major transmission diagnostic
job.

Can the "clunk" be blamed on a tread mismatch? The newer tires have
~2,000 highway miles on them and I'm pretty sure my alignment's fine. I
can get a tread gague if that'll help people's answers. Thanks in
advance!

-b

 

[Fuzzy Logic]

I've reviewed some of the threads but I'd like to revisit a tire topic.
Bear with me if this seems like a long post:

- I have -- and love-- my 99 MT Subaru Forester S. I replaced the stock
tires with 4 Kelly Navigator Golds ~50,000mi and I have ~77,000 miles
on the car now.

'bout 3 months ago I struck a rock on the highway, which tore the
sidewall of a front tire and dinged its wheel to the point that they
both needed to be replaced. The local tire dealer recommended 2 new
tires (same Kelly's), which I bought and had them mounted to the front
axle.

More recently I've noticed that there's a "clunking" noise/sensation
from the front wheel wells (you can feel it in the steering wheel/stick
shift), only when I'm slowly turning the car with my steering wheel
turned to the extreme right or left. The feeling's only intermittent
and fortunately's not present with regular driving and turning at
intersections.

I brought my Subie in for an inspection and they recommended I buy 2
new tires first, before they try to do a major transmission diagnostic
job.

Can the "clunk" be blamed on a tread mismatch? The newer tires have
~2,000 highway miles on them and I'm pretty sure my alignment's fine. I
can get a tread gague if that'll help people's answers. Thanks in
advance!

Subaru generally recommends you replace all 4 tires unless the difference in
circumference is less than a 1/4". More info here:

http://www.subaru.com/owners/carcaretips/index.jsp?
pageid=tire&navid=TIRED_TIRES

 

[Jim Stewart]

Hi all--

I've reviewed some of the threads but I'd like to revisit a tire topic.
Bear with me if this seems like a long post:

- I have -- and love-- my 99 MT Subaru Forester S. I replaced the stock
tires with 4 Kelly Navigator Golds ~50,000mi and I have ~77,000 miles
on the car now.

'bout 3 months ago I struck a rock on the highway, which tore the
sidewall of a front tire and dinged its wheel to the point that they
both needed to be replaced. The local tire dealer recommended 2 new
tires (same Kelly's), which I bought and had them mounted to the front
axle.

More recently I've noticed that there's a "clunking" noise/sensation
from the front wheel wells (you can feel it in the steering wheel/stick
shift), only when I'm slowly turning the car with my steering wheel
turned to the extreme right or left. The feeling's only intermittent
and fortunately's not present with regular driving and turning at
intersections.

I'm no expert, but your problem sounds more
like a bad CV joint or steering linkage problem.
You can crawl under the car and visually inspect
the CV joints with nothing more than a flashlight.
They are the black rubber bellows-like things
that fit around each end of the halfshafts going
between the wheels and the transaxle. If any
of the boots are torn, they will quicky allow dirt
to get into the joints and destroy them.

While you're under there, look for any broken or
rubbing steering or suspension gear.

 

[Juan Vado]

More recently I've noticed that there's a "clunking" noise/sensation
from the front wheel wells (you can feel it in the steering
wheel/stick shift), only when I'm slowly turning the car with my
steering wheel turned to the extreme right or left. The feeling's only
intermittent and fortunately's not present with regular driving and
turning at intersections.

Bad CV joint. Classic symptoms. It will get worse.
It may have started when your CV joint boot was nicked
at the same time your tire damage occurred, allowing
water and dirt to contaminate the CV joint.

 

[Rick Courtright]

More recently I've noticed that there's a "clunking" noise/sensation
from the front wheel wells (you can feel it in the steering wheel/stick
shift), only when I'm slowly turning the car with my steering wheel

Hi,

As Jim said, check those CV joints--the low speed "clunk" w/ wheel close
to lock at one end or another is one of the "classic" symptoms of a
joint going bad. If the boots AREN'T torn, you're probably due for new
ones by now if they haven't been replaced before, with attendant
cleaning and regreasing of the joints. If a boot IS torn, you may find
it cheaper in the long run to swap out the complete axle for a
remanufactured one (go Subie OEM on that--voice of experience! The extra
cost is worth it.) You might also want to jack the front wheels up and
check for any looseness in the wheel bearings in addition to checking
everything else suspension related. There can also be some clunking
related to shocks/struts, but IME it's not related to wheel position
like the noise a sick CV joint exhibits.

On the tires, I'd put them low on the list of "possible suspects," but
you might want to rotate your new ones to the rear and see if the noise
is still there. And on the subject of tires, be sure to check the torque
on all your wheels. If you've got alloys, lugnuts can come loose more
easily than they do on steel, so that's yet another slight possibility.

Another poster mentioned Subaru's 1/4" circumference difference figure.
This has been discussed before, and I'm not sure I'm yet convinced they
actually meant circumference or diameter (as in missprint?) If you do
the math, that's only allowing a little more than 1/16" difference in
diameter! I'm skeptical of that figure--it just doesn't seem to be a
reasonable real world number.

Hope you find the problem easily!

Rick

 

[y_p_w]

Subaru generally recommends you replace all 4 tires unless the difference in
circumference is less than a 1/4". More info here:

http://www.subaru.com/owners/carcaretips/index.jsp?
pageid=tire&navid=TIRED_TIRES

It seems to be a one size fits all description. The mechanical
diff in his manual transmission car should be OK. I think the
big problem is how the more sophiticated Subaru electronic AWD
drive systems can go batty (working overtime) when they sense
the wheels aren't turning at the same rate.

 

[skibum]

Thanks gang--

I took a look a the CV boots and they seem intact, but maybe there are
some cracks that I missed. I'll bring them back to a local shop to get
a 2nd opinion about the clunk.

 

[Guy Macon]

It seems to be a one size fits all description. The mechanical
diff in his manual transmission car should be OK. I think the
big problem is how the more sophiticated Subaru electronic AWD
drive systems can go batty (working overtime) when they sense
the wheels aren't turning at the same rate.

My 85 Subaru doesn't have a front/read differential, and had a
lot of trouble getting out of 4WD mode when I bought two of the
same model tires a year later. Replacing all four at the same
time fixed the problem.