Tire Replacement

[Tony Johnson]

I recently acquired a nail in one tire. Haven't determined if the tire is
repairable but in case it is not I want to learn what options what the tire
replacement options are. I understand uneven relative thread wear between
tires can be detrimental to the all-wheel-drive train and braking system.

What are the tech specs regarding replacement of tires on an
all-wheel-drive Subaru Legacy sedan? Is there a thread wear differential
spec that would allow replacing less than all the tires, say only 2 tires or
perhaps 1 tire.

Tony Johnson

 

[mulder]

I recently acquired a nail in one tire. Haven't determined if the tire is
repairable but in case it is not I want to learn what options what the tire
replacement options are. I understand uneven relative thread wear between
tires can be detrimental to the all-wheel-drive train and braking system.

What are the tech specs regarding replacement of tires on an
all-wheel-drive Subaru Legacy sedan? Is there a thread wear differential
spec that would allow replacing less than all the tires, say only 2 tires or
perhaps 1 tire.

Tony Johnson

The rolling circumference (NOT tread depth or diameter) of all 4 tires
must be within 1/4".

 

[kstahl]

I recently acquired a nail in one tire. Haven't determined if the tire is
repairable but in case it is not I want to learn what options what the tire
replacement options are. I understand uneven relative thread wear between
tires can be detrimental to the all-wheel-drive train and braking system.

What are the tech specs regarding replacement of tires on an
all-wheel-drive Subaru Legacy sedan? Is there a thread wear differential
spec that would allow replacing less than all the tires, say only 2 tires or
perhaps 1 tire.

Tony Johnson

How many miles are on the tires?

Is it only flat on the bottom?

 

[y_p_w]

I recently acquired a nail in one tire. Haven't determined if the tire is
repairable but in case it is not I want to learn what options what the tire
replacement options are. I understand uneven relative thread wear between
tires can be detrimental to the all-wheel-drive train and braking system.
Yep.

What are the tech specs regarding replacement of tires on an
all-wheel-drive Subaru Legacy sedan? Is there a thread wear differential
spec that would allow replacing less than all the tires, say only 2 tires or
perhaps 1 tire.

I don't think there are any special requirements. Just get it
repaired to the Rubber Manufacturers' of America guidelines. It
needs to be taken off the rim to check for damage too severe to
repair. Always get it plugged to fill the area and patched to
properly seal the liner. A mushroom shaped plug/patch is ideal.

It will be a judgement call if the hole is too big or too close
to the sidewall. You might also need to get it rebalanced to
avoid uneven wear.

Is your's an auto - and what year? Some of the auto AWD systems
do a major freak-out if the tires aren't closely matched in size.
They have an electronically controlled transfer clutch that can
go batty working overtime if it senses the tires aren't spinning
at the same rate. The manual versions use a simpler mechanical
center diff.

 

[Fuzzy Logic]

I recently acquired a nail in one tire. Haven't determined if the tire
is repairable but in case it is not I want to learn what options what
the tire replacement options are. I understand uneven relative thread
wear between tires can be detrimental to the all-wheel-drive train and
braking system.

What are the tech specs regarding replacement of tires on an
all-wheel-drive Subaru Legacy sedan? Is there a thread wear differential
spec that would allow replacing less than all the tires, say only 2
tires or perhaps 1 tire.

From <http://www.subaru.com/common/faq/tech_info.jsp#4>

Do I have to replace all four tires on my AWD Subaru?

All of the tires on your AWD Subaru must be within 1/4 of an inch of rolling
circumference (part that touches the road). This is because of our All Wheel
Drive System.

Proper rotation of the tires at the appropriate service intervals will
increase the life expectancy of your tires. This will also ensure that all
four tires stay relatively equal in their tire tread wear. When vehicles are
serviced, tires should be routinely checked to ensure that the alignment and
tires are in good working condition.

 

[Edward Hayes]

Subaru states that tire circumference should be within 1/4 inch in
circumference which translates to about 3/32 inch difference in tread
depth on a 215/60/16 tire.(same size and model tires of course)

 

[Phil]

Try installing a tube in the tire when repairing. A nail can cause enough
damage so that the tire is unrepairable as a tubeless tire but quite okay
with the tube in. Save any mismatch with wear that way.
phil

 

[Ragnar]

Try installing a tube in the tire when repairing. A nail can cause enough
damage so that the tire is unrepairable as a tubeless tire but quite okay
with the tube in. Save any mismatch with wear that way.
phil

I would think that if you tube one tire you will want to tube all four.
Balance issues.

 

[Edward Hayes]

Tubes in radials create a safety issue due to friction between the
tube and the tire casing. The result is high heat and blowout. Any
tire web site will advise against it. ed

 

[Rick Courtright]

Tubes in radials create a safety issue due to friction between the
tube and the tire casing. The result is high heat and blowout. Any

But IF one decides to tube a radial, make sure it's a ~radial~ tube!
Most sold today are, but one must check. A non-radial tube won't last
for the reasons Ed mentions. There ARE apps where tubes in radials are
necessary, such as a buddy's wire wheels on his old Triumph Spitfire: no
problems so far, and the car's been restored and back on the road close
to five years. And I use tubes from 20" truck tires for a non-auto app:
they're radial tubes, so I guess they can hold up to some tough use.

To this poster: I'm afraid I don't understand what you're saying. A
tubed tire can be balanced as easily as a tubeless. Are you referring to
unsprung weight w/ one wheel heavier than the others? If so, I'd think
the small additional weight of a tube is probably close to being a
non-issue.

Rick

 

[y_p_w]

Edward Hayes wrote:




But IF one decides to tube a radial, make sure it's a ~radial~ tube!
Most sold today are, but one must check. A non-radial tube won't last
for the reasons Ed mentions. There ARE apps where tubes in radials are
necessary, such as a buddy's wire wheels on his old Triumph Spitfire: no
problems so far, and the car's been restored and back on the road close
to five years. And I use tubes from 20" truck tires for a non-auto app:
they're radial tubes, so I guess they can hold up to some tough use.

But a tube wouldn't be needed in the OP's application if an industry
standard plug and patch is done. I don't believe tubes are in
common use these days.

 

[Edward Hayes]

Thanks Rick: I didn't know they made radial tubes.

 

[Rick Courtright]

But a tube wouldn't be needed in the OP's application if an industry
standard plug and patch is done. I don't believe tubes are in
common use these days.

Agreed--IF one can find a shop that does an "approved" plug AND patch
routine! I haven't seen it done in person for years, and I've picked up
enough nails to "keep track" as it were! If I had to establish what the
"industry standard" is simply from observation, it would be just a
patch... in the US, at least. I've heard (not documented) that the "plug
and patch" is required by law in many European countries--at least the
ones where they drive "fast" relative to the Americans. Anyone?

And you're correct on tubes--outside specialized apps, I'd guess they're
on the way to being an endangered species for automotive use.

Rick

 

[CompUser]

Agreed--IF one can find a shop that does an "approved" plug AND patch
routine! I haven't seen it done in person for years, and I've picked up
enough nails to "keep track" as it were! If I had to establish what the
"industry standard" is simply from observation, it would be just a
patch... in the US, at least. I've heard (not documented) that the "plug
and patch" is required by law in many European countries--at least the
ones where they drive "fast" relative to the Americans. Anyone?

It's required by law in some states, for repairs
of emergency vehicles (fire/police/ambulance), if
the tire is repairable.

 

[news.radiant.net]

you can do 1 of 2 things.
1 - get a new tire shaved down to the same size as the existing tires. A
race shop can do this, you better call around first.

2 - get 2 new tires. Put 1 new and 1 old on the front, and 1 new and 1 old
on the back. This will will minimize or eliminate driveshaft speed
differences between front and back. Side to side you don't have to worry
about because the differential will take car of that.
If you are going oval racing, put the two larger tires on the outside. )


I recently acquired a nail in one tire. Haven't determined if the tire is
repairable but in case it is not I want to learn what options what the tire
replacement options are. I understand uneven relative thread wear between
tires can be detrimental to the all-wheel-drive train and braking system.

 

[y_p_w]

y_p_w wrote:




Agreed--IF one can find a shop that does an "approved" plug AND patch
routine! I haven't seen it done in person for years, and I've picked up
enough nails to "keep track" as it were! If I had to establish what the
"industry standard" is simply from observation, it would be just a
patch... in the US, at least. I've heard (not documented) that the "plug
and patch" is required by law in many European countries--at least the
ones where they drive "fast" relative to the Americans. Anyone?

I don't know where to find a shop that can't do a proper plug and
patch. There were 3 tire shops within a half mile of where I used
to work, and each one could do a plug and patch repair. I suppose
the plug reduces the flex at the hole. Tires are sealed against air
loss with an inner liner, and only a patch guarantees a proper seal.

I don't trust that a plug alone shot from the outside isn't going to
shoot off. Even if it doesn't, there's no way to make sure the glue
completely seals the liner to prevent air from leaking.

And you're correct on tubes--outside specialized apps, I'd guess they're
on the way to being an endangered species for automotive use.

Some manufacturer's completely void the warranty if a tube is used
to repair a radial tire.

 

[Rick Courtright]

to work, and each one could do a plug and patch repair. I suppose
the plug reduces the flex at the hole. Tires are sealed against air
loss with an inner liner, and only a patch guarantees a proper seal.

Hi,

My understanding from casual research years ago is the purpose of the
plug is to seal the tire from external "attack" (in particular water)
while the patch guarantees air tightness. According to the sources I
read, water getting under the tread can cause rusting of the steel belts
and/or delamination between the tread and the carcass. The "rust"
problem seemed a little far fetched to me, since the steel is encased in
rubber material, but I won't argue yes or no on that front. The
delamination problem seems more likely, particularly as we go to more
"environmentally friendly" (read: may not work as well as the older
stuff???) bonding agents. I was told one of the prime suspects in the
original Firestone 500 radial delaminations (mid-'80s or so?) was
supposedly water-based bonding agents being compromised in tires that
had been punctured. I find that one easier to buy than the rust story.

Many mfrs today recommend (and, I understand, some states require)
replacement of radial tires at five year intervals regardless of wear
because of the potential for delamination as the bonding agents lose
their effectiveness (I'd have thought the vulcanization process during
mfr would override this, but I haven't kept up recent changes in auto
tire mfring technology to know what's still used, what's not. I
understand in some rubber mfring, "old style" vulcanization's being
replaced with less costly, and arguably less effective, methods)

One news report I saw on the subject indicated failure could even happen
on a tire that had lived its life as a spare, never previously on the
ground, when it was pressed into road service. I'd have taken that as an
"Oh, really?" kind of story requiring more data at first, but,
anecdotally, shortly after seeing this report, the g/f threw a tread on
a tire on her Civic--a hair over 20k miles, about half worn, never
punctured, but approaching five years in a rather warm environment. So
it would seem the change in bonding agents may be a more real problem
than originally thought. Because of that, I would think the RMA (Rubber
Mfrs' Assn or similar) would be pushing dealers to go the "plug and
patch" routine automatically, but at least here in SoCal, you'll
generally draw the "1000 yard stare" if you ask around.

I don't trust that a plug alone shot from the outside isn't going to
shoot off. Even if it doesn't, there's no way to make sure the glue

I wouldn't worry about "shooting out" if the plug is a mushroom head
design, but there's also the "rubber band" type plug that has no
shoulder anywhere. That one would be worse than worrisome to me! Either
way, I wouldn't trust ONLY a plug cuz of the sealing difficulties you
mentioned.

Rick

 

[y_p_w]

I wouldn't worry about "shooting out" if the plug is a mushroom head
design, but there's also the "rubber band" type plug that has no
shoulder anywhere. That one would be worse than worrisome to me! Either
way, I wouldn't trust ONLY a plug cuz of the sealing difficulties you
mentioned.

I was thinking of the plug-only fixes. Especially the ones using an
injector gun or one of those licorice like strands inserted with a
needle. Those things are emergency backups only.

I remember back in the days I rode a bike, I learned all about fixing
flats. One of the things I learned was that no glue was needed to
patch a "tubular" tire's inner tube. These tires are glued onto a
stronger box shaped rim. The repair was made by opening up the
casing, placing a piece of inner tube against the casing, and sewing
it back up. Pressure from the tire would press the inner tube against
the rubber patch and create a seal.

 

[Rick Courtright]

I was thinking of the plug-only fixes. Especially the ones using an
injector gun or one of those licorice like strands inserted with a

Yup, the "licorice" ones are the ones I was thinking of that would scare
me, too!

I remember back in the days I rode a bike, I learned all about fixing
flats. One of the things I learned was that no glue was needed to
patch a "tubular" tire's inner tube. These tires are glued onto a

That's interesting... I've punctured a LOT of bicycle tires (still an
avid cyclist) and always used glue on the patches for tubulars (or
"sew-ups" to many) before I gave up on them. There ARE "glueless"
patches available today, but not "back when" I was riding sew-ups. Were
you using actual "store bought" patches, or just bits from a discarded
inner tube? The "store bought" ones would have had some kind of adhesive
that I could see sticking under pressure. But "home made" patches from
an old tube wouldn't. I'm gonna pass this one on to some of my cycling
buddies to see if they ever did it your way! Thanks!

Rick

 

[y_p_w]

y_p_w wrote:

That's interesting... I've punctured a LOT of bicycle tires (still an
avid cyclist) and always used glue on the patches for tubulars (or
"sew-ups" to many) before I gave up on them. There ARE "glueless"
patches available today, but not "back when" I was riding sew-ups. Were
you using actual "store bought" patches, or just bits from a discarded
inner tube? The "store bought" ones would have had some kind of adhesive
that I could see sticking under pressure. But "home made" patches from
an old tube wouldn't. I'm gonna pass this one on to some of my cycling
buddies to see if they ever did it your way! Thanks!

Never actually did it myself. I read the instructions from a bike
repair guide. It recommended that pressure from the tire would press
the patch (just a cut up piece of inner tube) against the casing. I
don't see why a glued patch wouldn't work, but I thought the repair
guide's suggestion was interesting. I've actually used Park "glueless"
repair kits to patch a waterproof beverage cooler liner. The patches
worked fine, but that vinyl had a nasty habit of forming little tears
in the corners.

Actually - one of the strangest things that happened to me was a nail
that went clear through my tire, through two layers of inner tube,
the rim strip, and punched through a Campagnolo rim. I kept on riding
and wondered what this click, click sound was. It still had pressure,
but I noticed that nail. I installed my backup tube and rode along.
The rim had a hole, but was still completely true and rideable. I
don't ride much any more, but I still have that bike. It looks
rather ancient now, with a Columbus SL frame, down tube shifters,
and a freewheel.