Shelf Life of [Spare] Tires?

Had a flat tire on the return from the New Castle Regionals (USA) last
month and had to use the spare tire...the *original* (ca. 1992) tire
that's been inside the trailer the entire time. It looked brand new but
I took it easy driving back anyway. Now I'm wondering if a tire kept
out of the sun and off the ground has a finite life?

Google found some recent references to studies, with several cautions
that tires more than six years old should be replaced. Most refer to
tires on the vehicle but a couple related to tires stored in a
warehouse for over 10 years, then sold (with subsequent failure due to
"glue" weakness).

Anyone have any expert knowledge of whether the spare tires we carry
around for many years inside the trailers are still safe even though
they've got zero miles on them?

Chip Bearden
ASW 24 "JB"

wrote:
Had a flat tire on the return from the New Castle Regionals (USA) last
month and had to use the spare tire...the *original* (ca. 1992) tire
that's been inside the trailer the entire time. It looked brand new but
I took it easy driving back anyway. Now I'm wondering if a tire kept
out of the sun and off the ground has a finite life?

Google found some recent references to studies, with several cautions
that tires more than six years old should be replaced. Most refer to
tires on the vehicle but a couple related to tires stored in a
warehouse for over 10 years, then sold (with subsequent failure due to
"glue" weakness).

Anyone have any expert knowledge of whether the spare tires we carry
around for many years inside the trailers are still safe even though
they've got zero miles on them?

Chip Bearden
ASW 24 "JB"
Hello Chip,
I have 20+ years in the tire business. I highly recommend that
you "chunk" the spare. Give me a call or E Mail me if you want a
further explination Thanks, 5 Ugly.

wrote:


Anyone have any expert knowledge of whether the spare tires we carry
around for many years inside the trailers are still safe even though
they've got zero miles on them?

Chip Bearden
ASW 24 "JB"

Hello Chip,
I have 20+ years in the tire business. I highly recommend that
you "chunk" the spare. Give me a call or E Mail me if you want a
further explination Thanks, 5 Ugly.


Sam:

After how many years should we get rid of an unused spare and get a new one?

Greg

An update from a Wall Street Journal article yesterday (10 Nov 2005):
------------------
(TITLE) Bridgestone's U.S. Unit Advises Tire Life-Span Limit

Bridgestone Corp.'s U.S. tire-making unit has broken ranks with the
rest of the U.S. rubber industry in recommending a maximum life span
for passenger and light-truck tires.

In a recent technical bulletin to its dealers, the tire maker said all
tires -- including spares -- that are more than 10 years old should be
replaced, regardless of their external appearance. The company cited
the same recommendation issued in September by the Japan Automotive
Tire Manufacturers Association. Bridgestone is based in Japan. [more]
-------------------
The article goes on to state that many U.S. car companies have begun
similar recommendations, though with shorter lives; e.g., Ford started
urging its customers this year to replace tires that were more than six
years old. The main U.S. tire industry trade group disagreed, saying
there was no evidence to support a maximum service life. Bridgestone
conceded it was not aware of any technical data to support a max
service life, but was going along with the Japan tire makers'
association's recommendation.

It's difficult to separate the impact of liability concerns from actual
risk. My trailer spare tire had been stored inside the trailer for
nearly 14 years before I used it on the way home from the New Castle
Regionals in Sep. Although it looks brand new, given the above (and a
recommendation by Sam Giltner--see his earlier posting), I probably
won't run the spare on the trailer next year. The only real question is
whether to throw it away or move it back inside the trailer again for
backup duty.

It probably makes sense to rotate the tires to cycle through the spare
to avoid this situation in the future. Anyone doing that?

Chip Bearden
ASW 24 "JB"

wrote:

It probably makes sense to rotate the tires to cycle through the spare
to avoid this situation in the future. Anyone doing that?


It seems to me that you would put extra work into getting the same
result, Either way you end up with 3 tyres that have to discarded long
before they are worn out.

I used top think that tyre failures were fairly random and caused by
external events, but a few years ago I changed my mind. One weekend
driving a subcompact (Fiesta) at 75-80 mph to the glider port I had an
explosive failure of a rear tire. Next weekend the other rear tire
failed in the same way. Both tyres were the same age, about 5 years
old. Too old to be safe in Arizona it seems.


Andy

Andy wrote:

wrote:

It probably makes sense to rotate the tires to cycle through the spare
to avoid this situation in the future. Anyone doing that?


It seems to me that you would put extra work into getting the same
result, Either way you end up with 3 tyres that have to discarded long
before they are worn out.

I used top think that tyre failures were fairly random and caused by
external events, but a few years ago I changed my mind. One weekend
driving a subcompact (Fiesta) at 75-80 mph to the glider port I had an
explosive failure of a rear tire. Next weekend the other rear tire
failed in the same way. Both tyres were the same age, about 5 years
old. Too old to be safe in Arizona it seems.


Andy

My experience (in a very different climate in England) is that trailer tyres
get very iffy after 5 years or so due to sidewall cracking (normally
visible) caused by UV degradation of the rubber. I'd expect a spare tyre
kept on the inside of the trailer to last a lot longer than on the outside.

--
Real name is richard

My experience (in a very different climate in England) is that trailer tyres
get very iffy after 5 years or so due to sidewall cracking (normally
visible) caused by UV degradation of the rubber. I'd expect a spare tyre
kept on the inside of the trailer to last a lot longer than on the outside.

That's exactly my situation. The original (ca. 1992) tires had to be
replaced a while ago due to sidewall cracking (UV, ozone, oxidation,
whatever). The spare tire of the same vintage looks brand new today.

I see Andy's point--if the primary criterion is age and if we don't put
enough miles on our trailer to wear out the tires before they hit
whatever age limit we set, then it doesn't matter whether you rotate
the spare onto an axle or not. We should buy three new tires after
five, six, seven years anyway.

But if the tires will go a few years longer by limiting their exposure
to UV, it's a different story. Rotating the three tires through the
spare position every year, for example, means that no single tire would
have more than six years in the weather/sun until the ninth year of
service. Based on my experience, sidewall cracking is related to
exposure on the axle.

Whether we should be running a tire after nine years is the subject of
my original question, of course.

wrote:


But if the tires will go a few years longer by limiting their exposure
to UV, it's a different story. Rotating the three tires through the
spare position every year, for example, means that no single tire would
have more than six years in the weather/sun until the ninth year of
service. Based on my experience, sidewall cracking is related to
exposure on the axle.

RV owners frequently put tire covers on their vehicles tires, since they
often sit for months at time. This would work for many glider pilots,
and eliminate the need to rotate tires.

Whether we should be running a tire after nine years is the subject of
my original question, of course.

I don't have this answer, either. Personally, I'd be willing to have a
10+ year old spare that was in visually good condition, with the
expectation that if I had to use it, it would be at moderate speeds just
long enough to get to the nearest tire dealer for a new tire.


--
Change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

I don't have this answer, either. Personally, I'd be willing to have a
10+ year old spare that was in visually good condition, with the
expectation that if I had to use it, it would be at moderate speeds just
long enough to get to the nearest tire dealer for a new tire.

Yeah, Eric. That's how I got to this point. The spare looks like new,
worked fine all the way home for four hundred miles even at
not-so-moderate speeds, and now I'm looking at it saying, "hey, do I
really need to replace it?"

Chip Bearden
ASW 24 "JB"