by yrock87 » Fri Dec 09, 2016 2:05 pm
this is one of those preverbal "can of worms". you will find many opinions on tires and each camp has followers who are very vocal about their opinions.
ST, special trailer, tires are designed to withstand the riggers of trailer use. they have stiffer sidewalls to counteract the forces of jackknifing trailers (especially dual axle trailers) their tred resist the scrubbing from dual axle trailers making tight turns. they except very high PSI to accommodate the high weights of trailers and they allegedly are formulated to withstand being left unused for months on end better than passenger tires. I have even read that they withstand exhaust chemicals better due to their location behind vehicles. lastly they hold their shape better, not deflecting as much at the road surface, which decreases rolling resistance. a drawback to ST tires is that generally are limited to 55 mph. a few manufacturers allow you too add extra pressure at a given weight in order to go 65mph, assuming your load is light enough to add that extra pressure without surpassing the max pressure of the tire. nobody ever follows this "limit" but it is there none-the-less. ST tires are also more expensive than passenger tires. as a rule of thumb, standard passenger tires should be weight de-rated ~10% when used as trailer tires, ST tires do not have that limitation.
For what its worth, on a light TD I am using regular passenger tires, filled to about 28 psi. the trailer handles very well with this set up and after 1500miles I didn't see any excessive wear. these same passenger tires were originally filled to max psi (50?) and the trailer handled poorly. I am happy with my decision as the passenger tires are well within their weight rating and they provide a very stable ride at speeds in excess of 70mph.
I have also used passenger tires on my cargo trailer which made the 2400 mile trip from Fairbanks AK to the Seattle area. they also performed very well with a trailer that weighed 2400lbs. however my father is cursing himself for going "cheap" on his dual axle boat trailer by using passenger tires. his boat is heavy enough that there is significant deflection of the sidewall, which kills his MPG, he also experienced significant tread wear due to scrubbing of the tiers when maneuvering at ramps. his tandem axle car hauler handles better even when loaded down to nearly double the boat weight in large part because it has ST tires.