I'm got a '17 Prime. Came with Nanoenergy tires, and they have surprisingly good tread at 43k, though clearly they have wear. That 43k is probably 70% highway. I'm about to drive almost halfway across the U.S., 1500 miles each way. Primes don't have a spare. Would you get new tires to take that trip?
Have you measured whats left on the tire? If it's almost due for replacing I would replace them. And separately, I would get a spare anyways, new tire or old tire you can still get a flat.
take them off, inspect the inner and outer sidewalls. look for splits cracks dry rot bumps and slashes. check the date code also, you never know what is on there until you verify it. if they look great, go ahead and run them after you verify they're inflated properly. under inflated tires run hot and can degrade the carcass (blowouts!) quickly. before you leave for the trip, great a spare wheel/tire that is the same size as yours. junk yards have wheels cheap, install a new tire
I am NOT in favor of doing ANYTHING unusual right before a big trip like that. It will cause trouble sometimes that would not have happened otherwise.
Hmm. Considering my very bad tire-checking habits, that right there is a very good point. I over-inflate, then forget to check for three months. I don't want to spend the dough for new tires (I'm in the middle of a very expensive divorce), but it would be far worse to get stuck somewhere in rural PA with a blowout. And I am definitely going to look into a spare right away. Never felt the need, but I've never driven solo this far in this car, either.
Somebody from Western MA worried about rural PA. Now I've seen it all. Jokes aside, I probably would not worry about 43k on 5-year old tires... but I would still inspect them or pay somebody to do it.
That brings out another good point, the TPMS in the car normally doesn't light the warning light until a tire is significantly below the set pressure: if you have set the TPMS with the tires inflated to, say, 35 psi, you won't see the yellow light until a tire has dropped well into the 20s. My answer to that was one day I went out and aired up all the tires to the sidewall max pressure, 41 or something, pressed the TPMS set button for that, and then let them back down to my usual pressures. The yellow light stays off at my normal pressures but now will come on just a couple psi below them, so I get warned before the pressure is crazy low. Of course it means I get the yellow light more often (any good cold snap'll do it), but I have a compressor handy so I don't might airing them up whenever.
Ha! Well, at least in Western Mass, you're never far from a town. One of the least-pleasant travel experiences I've ever had was a breakdown in the countryside kind of near Wilkes-Barre -- a very long and expensive diversion.
I grew up 30 minutes west of Wilkes-Barre in a somewhat less populated area. Great place to grow up, but if not from the area and out in the sticks, I could see an expensive visit. We just did a trip along the pacific coast highway out here on the best coast in our 2019 Prime with 39k miles on it and the original Toyo tires. Sections of the highway there are switch backs and other sections are sharp bends that have speed, and I didn't think twice about it. Make sure the tread depth is fine and the sidewalls are in good shape with no cracks and you should be fine. I have a donut spare though for piece of mind.
What is their tread depth? As someone raised in rural parts of the Pacific Northwest, and has crossed PA only once, I just have to ask -- how far from town can you get in rural PA? This is what I'm used to (fuel intervals were even longer): (I don't have my own images of these, so just scarfed up some from the web.)
Even without a kosher tread depth gauge, you could cobble something. Say a chopstick, tongue depressor paddle or similar: place in tread, score with knife at tread surface, measure. And inspect the tires for cracking, sidewall gouges, etcetera. Beats internet opinion poll.
the wear bars will show if they've worn even, and also show if they're beyound service life. the tread depth is less important than the sidewall condition, cracks and dry rot will kill a tire in a hurry
Tiny surface cracks are NOT a problem. If you look close enough, you can find them on most tires over 2 years old or so. And ......modern tire compounds do NOT "dry rot", which is a specific condition that affected old formulation rubber that is not made anymore.
what do you define as "modern" ? the last 3 cars and 2 trailers I've purchased had dry rotted (my ignorance if a better term) tires
"Dry rot" is a specific condition where the rubber compound totally fails and falls off in chunks ranging is size from almost a powder to a small marble. It happened with compounds that used a high percentage of real natural rubber. It has not been a serious problem for.....oh......about 70 years or more. Modern tires can dry out and become brittle but that is a somewhat different condition.
the results for searching "dry rotted tires" on Google are what I'm referring to. the tires were cracked both inside the tread, the sidewalls, etc just like all the pictures that Google references.... when I was a kid it was called "dry rot" and apparently the definition hasn't changed today dry rotted tire - Google Search
OK, I give up. "convention" has bastardized the term. All cracking of rubber tires is NOT a sign of true "dry rot".......but that is the way seemingly everybody wants to use the term these days. This is probably mostly because virtually nobody alive today has actually SEEN real dry rot. And yes I am OLD.