Have You Done Any Mods?

I'd be delighted to cross paths for a visit.  We left the far west smoke for the green east coast, but my heart is still in the forests of the west.  By an odd set of circumstances that I won't go into here, I was born in Seattle but went south to CA at a very young age.

Marv' it's not an issue of being "legal" or "illegal," but rather an issue of making your self legally liable if something goes wrong.  You can put any tire on a trailer that you like, but if you have an accident, someone like me -- before I retired -- would end up defending you at the request of your insurance company for negligence and the company would probably pay a lot of money in your behalf, only to squeeze it out of you later as your loss history would be a lot worse.  If it was incredibly gross negligence, then there could be liability for criminal negligence but you'd need a different kind of lawyer than the tort defense practice I had.

gpokluda, there are all kinds of engineers just like there are all kinds of other professionals.  I wouldn't have my gastroenterologist do a heart valve replacement on me and have high expectations of a successful surgery. ... and I probably wouldn't like the approach to my heart s/he might attempt.  I used to defend tire companies and worked with some very capable engineers whose specialty involved tire design.  Those are the kind of engineers I'm talking about.  A software engineer or electronic engineer may not really fit the bill.  I doubt any real tire engineer would recommend using LT or P tires on a trailer carrying the weight of the typical travel trailer, even the light weight ones.

As for dealers and travel trailer companies putting on LT tires for show, the'll need a pretty good lawyer to wiggle out of the law suit when the tire engineer says the tire makes the trailer defective and the rules of product liability are applied.  If one sells a defective product and someone gets hurt, there is strict liability.  The difficulty for the plaintiff's attorney is proving the defect, as opposed to driving 90 with a trailer on a bumpy road, was the cause of the crash.  If I were a corporate lawyer for FR or another trailer company, which thankfully I'm not, I'd caution against putting LT tires on trailers.  If they want the gnarly look, get some of the Westlakes I linked to above, and charge $500 more for the trailer.

Thanks for the information.  65 it is.

I found out that its not illegal for a dealer to put any tire he wants on a trailer even if its not recomended.  I think in my case they put it on to make the used 178 trailer more attractive.

If you really feel the need for and/or will be driving in snowy conditions with your trailer, there are ST tires available with snow tread.  eTrailer has some, but they're pretty pricey, [https://www.etrailer.com/Trailer-Tires-and-Wheels/Westlake/WST34FR.html]. For most of us, we don't do much snow camping and in the off chance one must occasionally travel in snowy conditions requiring the extra traction, chains may be an easier and less costly alternative.  Also keep in mind that some states require trailer tires to be chained up when there are chain controls in effect for other vehicles, even for 4x4's with snow tires.  Best to check the rules where you anticipate snow driving before leaving.  For example, https://dot.ca.gov/-/media/dot-media/documents/chainrequire-a11y.pd.  Personally, if I had to confront driving in the snow with treacherous conditions or chain controls in effect, unless I was trying to run from the sheriff, I'd just wait until the weather improved and/ or the chain controls were taken down.