I have a 2004 Ford Ranger with a 2003 spare tire–235 70 15 here in north central Texas. It is parked on the drive, but the tire being under the truck it does not get that much UV light. The tire does not have any cracks that I can find and is holding air. But it is nearly 20 years old. Is it time to replace this tire? I sometimes am driving on back country roads, and don’t really want to get stranded.
If it was mine, I would replace it.
At least the next the next time you buy new tires, have the best old one put on the spare rim if it will fit.
5 Likes
My problem is the ones I replace have too many sun-induced cracks. Working on cleaning out the garage!
I had this issue recently with my 2004 truck. I bought a new tire and a used matching aluminum wheel to match the other 4 new tires. I’ll do a 5 wheel rotation from here on.
An 18 to 20 year old tire is dangerous and should not be relied on.
3 Likes
The tire might not be cracked now, but it will be after a few days of operation. That’s because cracking is both a function of the condition of the material AND how much stress is material has been subjected.to. That spare hasn’t been subjected to any stress yet!
No, replace the tire. There’s a reason why tire manufacturers recommend replacing tires after 10 years.
3 Likes
I think it makes sense to replace it.
One more vote to replace it. North central Texas has frequent ozone alert days, so even though the tire doesn’t show cracks, it’s been exposed to ozone for years, which seriously degrades rubber.
Makes common sense to just replace it. The alternative – providing it has no obvious defects and holds air ok – is to use it only for the occasional flat-tire situation, and then only for driving less than 25-30 mph.
I had a spare tire even older. It looked okay. When I had to put it on, it failed catastrophically, in a dozen places all around. Fortunately I was on an unbusy city street, have a spare and tools. It would have been awful on the freeway. Back country roads sound like a safe place to have a tire fail, as long as you can replace it. I’ve done a few repairs on them, including swapping in a spare.
From personal experience I had similatly aged tires with great tred on my classic,
Then took it for a drive and the rubber lugs were literally falling off the belts , thankful I made it home in one peice.
So let’s see… $100 or less for a descent spare, $200 for an “I need it now” replacement or $300 for for an emergency tow plus the above tire cost with a lifetime of your “significant other” commenting on your intelligence?
Seems simple to me. A decent spare tire is cheaper than a divorce and less risky than an irritated and pissed off “significant other” but go for it and when you have a flat, let us know how works out for you. . 
.
.
.
Might want to hit the junkyards, should be able to pickup a decent used tire already mounted for $50 for a spare
1 Like
+1
As the old saying tells us…
The man who wants to save the most money frequently winds up paying the most money.
A friend of mine disagreed with me when I told him that he should replace his 7 year old battery before he wound-up being stranded somewhere. Sure enough, a few months later, he was stranded–at night–with a dead battery. In addition to the cost of the road service, he had no choice at that point regarding where to buy the replacement battery, and–all told–he probably paid ~$200 more than he would have if he had replaced that old battery proactively.
Okay, folks, thanks for the advice. I replaced it. I asked one of my tire engineer friends, who told me to wait. Two days later a Fed-Ex truck dropped off a new tire. Apparently, it is a loan.
Mine is also a 2004 truck. It has been stored for awhile, has all of 30,000 miles, and I have decided this will be my personal truck. The other tires are about nine years old. The cracking is not severe, but they are scheduled for replacement. It needs some paint touch up and a new headliner, detailing, runs great.
Here’s a quote of yours from another thread.
“I have left in my retirement years, let me assure you that I still have friends and family who are tire engineers in the same big five tire company I worked for who still concur with me.”
You seem to be the tire expert, why are you asking us 
3 Likes
I thought I answered this. I have OCD. I have good days and bad days. That was probably a bad day. It is an OCD thing to double check and double check before taking an action. I needed the push to get me to act. (It looks so pristine.) I think it was gone before anyone replied. It is a strange thing to live with. I lock the bathroom door when nobody else is home, washing ritual, etc. I am great with detail work but can be too much of a perfectionist. All that stuff. So I have tons of stuff that really should go, but I get wrapped up in the possible intrinsic value of stuff, etc. Be glad you aren’t living with it. I hope this didn’t trouble you too much.