Age vs. Beauty and PSI

[NYJoe]

Question for the group about tires. We experienced our first China Bomb blow out of my Castlerock on our single axle trailer last time out. Swapped in the Westlake spare (mfg Jun 2020, max PSI 80) to get us to the nearest tire shop. Since it was the beginning of the trip, I didn't want to travel w/o a spare. They only had a Gallant (mfg Aug 2021, max PSI 65) in stock so I had to bite the bullet and buy another China Bomb. At home I just bought 2 Goodyear Endurance online and await delivery. Not crazy about an online purchase since the mfg date is an unknown. BTW all the local shops said these were on backorder w/o a restock date.

Which tire should I keep as a spare? The brand new, never used Gallant which has a PSI of 65 or the older Westlake with minimal miles that will match the PSI of the Goodyears max PSI of 80?
The Westlake - load range E; speed rated - L
The Gallant - load range D; speed rated - L

GVWR of the single axle trailer - 4700 lbs so both are within spec. I always try to keep our driving speed to 60-65 mph and trailer weight under 4000 lbs.

Interesting that the Castlerock (mfg sept 2017) that blew was my spare that I rotated in and only had about 200 or 300 miles on it. I always cover my tires to prevent UV damage when the trailer is parked. The other original Castlerock has around 8000 miles and will be discarded.

[TandW]

Since no-one else has chimed in I would stick with the tire that best supports the tire PSI recommendation for the RV.

[NYJoe]

My thoughts were that since the GYs are a much better tire and at the higher PSI, I wanted to match the spare with the GYs PSI. I was going to keep the brand new Gallant unmounted in the back of the pickup. The "new" Gallant is currently 12 month old, the Westlake is 30 months old.

I was also going to run the GY's at about 75 PSI for a bit softer ride.

[Mordecai]

Yup. Match the psi. If your spare rim is the same as your road wheels you could put a GY on it and rotate it in the beginning of every season.

[JIMNLIN]

On a single axle trailer its important to use the same type/load range/tread design/size on both ends of the axle.
Biggest reason being having equal braking especially on wet pavement in a panic braking situation. If you mount the odd spare just something to keep in mind.

A 4700 gvwr single axle trailer = 2350 lbs per tire.
At 4000 lbs = 2000 lb load per tire.

Single axle trailers tires don't side scrub like multi axle trailers so a lot of reserve capacity isn't needed above rated axle capacities.

I've always used a premium usa made P tire (or LT C load range if available) on single axle and tandem (7k and under)axle trailers with 14" or 15" wheels. No speed restrictions with the P tire.
Todays P tires can have up to 51 psi so rolling a bead off the rim isn't a issue like our old P tires with 32 max psi were.

[NYJoe]

Would running a tire with a max PSI require special valve stems. I've see metal ones on line.

[JIMNLIN]

Just plain old rubber stems up to 60 psi.
Above 60 psi I use the 100 psi rubber/brass centers.... same type on our 3/4 and one ton trucks. I use this type on all P and load C/D/E tires.

Above 100 psi you'll have to use the metal clamp in types.