If you have a Jeep, truck or SUV with a spare tire hanging out outside, I recommend putting a cover on it. Not just for the self-expression opportunity; (prime real estate for a Life Is Good stick figure!) but to make your tire last longer.
Tires are alive. Well, not really, but they are somewhat organic. Maybe it’s easier just to say: like a muscle, they work best when exercised. And when they sit in the sun without moving, they wrinkle and crack and can get used up without getting a single mile on them.
If a tire gets driven on, it gets flexed and heat-cycled. As a result, the tire stays supple like the skin of a healthy mammal. If it’s never worked, the sun’s UV rays make it cracked and uneven like the skin of a reptile. But unlike a crocodile, a cracked tire isn’t tough at all. It’s brittle and at high risk of popping.
Of course, all your tires are out in the sun for the same amount of time. But they’re engineered to be used, so when you roll about your business, the tire’s flexing keeps it supple. The unused tire doesn’t get that.
Ideally, you rotate your tires often enough (like every other oil change or so) that no one tire is ever out in the cold on an external mount for too long. But if you don’t drive that often, or if you’re like me and sometimes leave one of your vehicles parked for a couple of months and totally forget about it, a cover can go a long way toward prolonging the life of your spare.
Covers don’t always look cool though, so chose carefully. I waited about eight weeks for this fake JDM-looking Mitsubishi tire sleeve to get to me from southeast Asia via eBay and now it’s one of my favorite mods.
Update: Mention of UV degradation specifically has been added for clarification!