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So my tires are 5 years old and the spare apparently is even older and I went to do my winterization at my storage facility and found that a tire was flat and figured I might as well change them all out. Right now I have ST215/75D14 which are bias ply, I mainly haul on the highway and store in a gravel yard I was wondering if radial was better for my uses. I only haul to the mechanic/ to my driveway pre and post season and then to and from the ramp at the start and end of the season. The tires probably only have at most 1000 miles over the 5-6 years on them. Any input and suggested brands is appreciated.

Hi!

I just went through the replacement of the tires on my dual axle Sealion trailer and learned/re-learned a lot.
(I attempted to post a reply earlier but must have lost it...Sorry )

The date of manufacture of the tire is the critical item, not the date of purchase or installation.
ALL tires age internally and the clock starts at time of manufacture.
Most manufactures limit any warranty to no more than 6 years from manufacture date.

Figuring out the tire date:
The U.S. Department of Transportation (DOT) National Highway Traffic Safety Administration (NHTSA) requires that Tire Identification Numbers be a combination of the letters DOT, followed by eight to thirteen letters and/or numbers that identify the manufacturing location, tire size and manufacturer's code, along with the week and year the tire was manufactured.

"When it comes to determining the age of a tire, it is easy to identify when a tire was manufactured by reading its Tire Identification Number (often referred to as the tire's serial number)."

Tires Manufactured Since 2000
Since 2000, the week and year the tire was produced has been provided by the last four digits of the Tire Identification Number with the 2 digits being used to identify the week immediately preceding the 2 digits used to identify the year.

Example of a tire manufactured since 2000 with the current Tire Identification Number format:
DOT U2LL LMLR 5107
51
Manufactured during the 51st week of the year
07
Manufactured during 2007
While the entire Tire Identification Number is required to be branded onto one sidewall of every tire, current regulations also require that DOT and the first digits of the Tire Identification Number must also be branded onto the opposite sidewall. Therefore, it is possible to see a Tire Identification Number that appears incomplete and requires looking at the tire's other sidewall to find the entire Tire Identification Number.

The use of a partial Tire Identification Number on the one sidewall (shown above) reduces the risk of injury to the mold technician that would have to install the weekly date code on the top sidewall portion of a hot tire mold.

What Tire Dealers and Manufacture Reps recommended:
Trailer tires are primarily replaced for age and condition, not mileage.
ANY intra-tread or sidewall cracking is cause for removal and should not be used for transportation on public roads or highways. Cracking exposes the core of the tire to substantial degradation and may result in rapid or catastrophic failure.
The chemical binders used in the construction of tires degrade over time and result in the inter-ply separation between the construction layers.

--> To make your tires last:
Move your trailer regularly. Don't let it sit on one position.
Keep your tires properly inflated all year long. Especially in the winter when temperatures drop in which lowers tire pressure.
Avoid letting tires stand in water, mud, damp earth or grass.
Protect tires from prolonged static sunlight (with covers or UV inhibitors).
Use the properly rated trailer tires for the load and the trailer frame rating. (S/B on the trailer mfr. data plate or available from the trailer manufacturer or trailer literature.)
Use trailer tires on trailers and auto/truck tires on auto/truck. Don't mix.
If possible, unload your trailer tires by raising the trailer frame onto properly rated jack stands to safely get the tires off the ground. (Personally not sure how I can do this on the gravel surface I'll be parking on....)

-->> What I have seen is instances where inground contact Pressure treated lumber is used to raise the tires up off the dirt/grass/water and also to adequately distribute and stabilize the jack stands when those are used.

So all that said on to the difference or benefit of Radial or Bias-ply:
That seems to be a matter of personal preference as they both tend to be replaced for age and condition rather than mileage. The trailer manufacturer seems to be the best source for advice on aftermarket replacements what may work best for their trailer design based upon the type of axle, suspension, braking systems and load considerations . (The trailer manufacturer wants you to be happy with your trailer as that helps sell more trailers to more people.)

Brands:
There are several brands out there and it depends upon your region and what is actually available given the current market for tires with the supply chain disruptions that have occurred due to COVID-19 issues.
I'm not an expert in any way shape or form on what particular tire is better than another.
There are quite a few trailer tire manufacturers starting with just about all the major brands like Firestone, Goodyear, Cooper, etc.. Other Brands that I have found when I was researching this topic for myself were: Carlisle, Maxxis, Freestar, Wheel Express, eCustomRim, Grand Ride, Trailer King, Load Star, Hercules. This is something that is only you can decide for yourself. (Thank Goodness for the Internet!!!)
I hope this helps.

macowneril2015 wrote: ↑Thu Nov 05, 2020 4:52 pm So my tires are 5 years old and the spare apparently is even older and I went to do my winterization at my storage facility and found that a tire was flat and figured I might as well change them all out. Right now I have ST215/75D14 which are bias ply, I mainly haul on the highway and store in a gravel yard I was wondering if radial was better for my uses. I only haul to the mechanic/ to my driveway pre and post season and then to and from the ramp at the start and end of the season. The tires probably only have at most 1000 miles over the 5-6 years on them. Any input and suggested brands is appreciated.

Pertaining only to the question of Bias or Radial, I found this.

Bias tires are less expensive. Trailer owners sometimes say that because trailer tires are followers, that is, they follow behind the vehicle that pulls them, better performance is not as critical as it would be for the vehicle that pulls the trailer. The vehicle in the front does all the fancy work, while the trailer in the back mostly just rolls forward.

Radial tires, however, do perform better than bias tires, and that performance is quickly noticeable.

The ride is smoother, the trailer does not bounce and sway as much, and radial tires have a longer life.

The most important characteristic of any trailer tire is its ability to carry a heavy load. In the past, bias tires were known to carry heavier loads than radial tires. That has changed. Nowadays, radial trailer tires are designated with the “ST” label in their name, short for Special Trailer, and they are built to carry heavy loads. If you have been using bias tires for years because of their load capacity, you might consider taking a look at ST radial tires

Yours apparently are ST radials. Now it comes down to money. That is a personal decision.

Since you’re in the middle of the big change. This ought to be the time to consider 15” vs 14”. You may be able to go up to a class D tire easier; Although I did find 14’s in a class D, they’re unicorns. Sadly, I did this on a busted A$_ rusted out tandem trailer that I ended up having to write off on my last 1500 mile highway adventure. I’ll send a link if relevant, later. I’m still trying to move on from it, lol. But if you’re re-examining tires, analyze soundness of trailer & ~ 2 next years of plans...

Gazmn wrote: ↑Fri Nov 06, 2020 7:16 pm Sadly, I did this on a busted A$_ rusted out tandem trailer that I ended up having to write off on my last 1500 mile highway adventure.

Still makes me cringe to remember that post.

Unless you are putting a LOT of miles on your trailer the tires will wear out from age long before the tread is showing any significant signs of wear. I've always used bias ply tires on my trailers. The load capacity per dollar spent was much better for bias and I just could not see the point in spending the extra money for a radial.

Just replaced my 2 trailer tires with towmaster ST215/75R14 LRD from COSTCO $68.99 ea.. Shipped to my house, no shipping cost, had them mounted and balanced $5 each at local garage. Towing like night and day. Just my 2 cents.

I appreciate everyone's feedback, I think i will end up going with the same I have used since I looked deeper into it and realized the trailer recommends it as well. I do appreciate the advise on maintenance for them, I will get covers for the tires and will get them off the damp ground.