I just had to put the spare tire on the 2004 Camry I inherited from Dad about 5 years ago. This tire is untouched (I think this is the first time the jack has been used). I know the common wisdom here is that sunlight (UV) causes tires to age out in about seven years. Any wisdom on how long a tire will last in the dark?
Yes, 10 years is a lot of time–even for a tire that has spent its time in the dark–but I think that most of your concern should be in relation to how you are using that spare.
If you are just using it as a very temporary substitute in order to get to a tire repair place, then I wouldn’t worry too much about it. On the other hand, if you are one of those folks who puts a spare on the car and then proceeds to drive around for days or weeks at a time, then I think that you should replace it.
Some years ago we sold a 1977 Dodge Colt for scrap. The car was 19 years old and the spare (full size) had never been used. It still held air and showed no cracks.
On the other hand, our camper trailer had a rear mounted spare and it, as well as the other tires, needed replacement due to cracking after 13 years, although all the tread was still there.
So, if the spare holds air and sits in the dark, it should be OK. Keep in mind that these small doughnut spares are rated 60/60. That means they are limited to 60 mph, and no more than 60 miles of driving. Since they are pressured up to 60 psi, it’s more critical that they hold air. If I found they did not, I would promptly replace them. In other words, if your little donut is used for 60 miles to get to the next garage, it’s probably toast.
An additional precaution is to carry a small electric tirepump with you so that you can power up the spare if necessary.
@art1966., There are many reasons I don’t like those temporaries and age is one of them. I now favor keeping full sized spares around. They often fit well enough in the spare compartment, and mostly in the same way. The weight difference is negligible. You just need an extra wheel (salvage yards, craigslist, etc.). When I get new tires, I have the best old tire transferred to the spare and the old spare gets discarded. So my spare usually maxes out at maybe 6-7 years old. (3-4 on the road / 3-4 in the trunk). And you can just toss it on and drive as normal. Just a thought.
Thanks for the comments (and more would be welcome).
I neglected to mention that this spare is a full-size OEM tire. In cars with space-saver spares, I, too, put in the best available used (but OK) full-size, even if makes the well cover in the trunk ride a little funny.
I forget the exact history on this Camry, but I wound up replacing tires in pairs, and the OEM spare just got left in the trunk.
If you’re not comfortable identifying dry rot on a tire, have the spare tire inspected by a trusted mechanic or tire technician. I don’t really care how old a tire is if it still does its job, and a tire stored out of the sunlight can be good for a long time.
Sun is one factor, ozone is another. So if the car spent a lot of time in, say, LA, it could still have a bad tire. And rubber hardens with age regardless. So I would replace it if I was going to keep the car. Maybe put the best worn one on it when replacing other tires, if that one wasn’t too old.