You know my trailer came with car tires and to be honest I haven't had any problems with them.

And I'm guessing that they put the car tires on as the trailer as trailer/car combination is not supposed to exceed (something like) 5500#'s. Or it might be 6K.

But wouldn't 6 or 8 ply tires be stronger and less likely to have an issue with the kind of hauling we do?

I know Dan Thompson has had a lot of experience with trailers and such, maybe he will have some opinions?

I would use a "trailer" tire on trailers and car tires on cars....From what I understand, trailer tires are built for the twisting that they go through when it is turned. The sidwalls are built different than car tires. Car tires aren't made for the twisting that they go through and I would think that you could tear apart the side wall renforcements....Trailer tires are marked on the side "for trailer use only". I wouldn't use any that are about 8 years or older either. I just had to buy a new set because the trailer tires on it were too old. Dry rotting from the inside is what you can't see. Would rather not have flat(s) on a trip even though I have a spare. I'm pullling a 24' enclosed trailer with car, tools, gas, set tire/wheels, ect. Even if I were just pulling a open trailer, I would use trailer tires...........

gotta go with jt here - and trailer tires are pretty cheap really. I just had to replace one about a month or so ago and it was something like $65 installed at my local Big O (The Big O guys treat me really, really well - installed my slicks for free one time because it took them longer than they told me. The place I went to first could even get them on!! so I paid 'em all with tip instead).

I have watched how twisted the inside tires get when pulling out of my driveway - HOLY CRAP it is NUTS how much those tires twist and roll over to make a simple turn.

With all the above. I put 4 new trailer tires on my open trailer last year. Was like $300 installed . My old tires had plenty of tread on them, but one was starting to show signs of dry rot so I just went ahead and replaced them all. I also rotate my tires once a year including the spare.

YMMV

In CA a trailer is supposed to have trailer tires and I have heard of several racers who were stopped for speeding having the trailer safety checked and the type of tires and their load range was one of the things the CHP officer checked. They had enclosed trailers so they had fairly heavy duty tires so there was not an issue although one got lack of a break away switch added to the speeding write up.

One difference between trailer and car tires is trailer tires have a UV blocker, because trailer tires sit in the sun more that car tires. Read it in a RV mag. Actually RV mags and forums are a great source for info on trailing.

I now carry two spare tires for my trailer.. a few years ago I had a two tires let go on the same trip

That's not uncommon.. Once one goes, the others are close behind it seems. Its prudent to just replace all tires at once after about 5 years due to failure from the inside.

Randal,
for your trailer I would be using trailer tires (ST) with at least a D load range rating.
I know your 914 does not weigh much, but you do use it for hauling much heavier items from time to time....(how do I know that ) And your trailer is no light weight all my itself...
ST tires are built especially for trailer usage. Stiffer side walls that are less likely to fail from flex etc...

Thanks again for allowing me to use your trailer....it really helped out...

I have a friend that "borrows" trailer tires from WalMart for long trips. He drives down to the Keys for lobster season and "buys" two extra tires from Walmart. If he doesn't use them he takes them back. Cheap bastard.

used to rip sidwalls out on the boat trailer all the time. Went to trailer c tires and never had a problem again. Went with cheaper bias ply tires cause it seems the sun/age kills em before they ever go bald.

A friend of mine in the race tire industry told me he got a chance to meet and talk to an engineer for a major USA tire manufacturer and was one of the designers of ST trailer tires. My friend asked him what owners should do to minimize the high failure rate lots of people experience with ST trailer tires. The engineer said that ST tires should be run 5 psi over the max cold inflation pressure molded on the tire and Never Ever exceed 55 mph. He also commented this was not a gaurantee but that it will increace the life of the tire enough to last the 3 years they are supposed to live.

And I have done the P series tires on trailers too and can attest that they don't work and live as well as an ST does in the same conditions.

I started partially doing this and found that my ST tires did last longer and towing at only 65 mph noticebly helped decrease the fuel consumption of my F250 with a 7.5L big block V8. This was before gas went the high side of $2 per gallon a few years ago. Of course the climate of the southwestern desert is not good for tire life anyway.

I even looked into converting my trailer to LT rated tires so the higher legal speeds would be ok with tire life but ran into costs in the realm of $150 ~ $200 ea. in sizes that I'd be able to get at almost any tire store if I lost one on a trip.