Shelf Life of [Spare] Tires?

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"