* All the tire manufacturers and trailer experts (professional businesses that have a reputation to uphold, and/or financial/legal culpability to their customers) usually maintain that tires are best run at recommended tire pressures.
* On cars & trucks, there's a recommended tire pressure on a sticker inside the door (or in the user's manual) that shows what tire pressure the mfg. has tested the vehicle to be safe to operate at, even if the tire mfg. has a different pressure listed on the tire (max cold air pressure...a fall-back #, safe to use on whatever
unknown vehicle the tire may be installed on). There are exceptions to this "rule", though.
* Special usage tires!... that I've had some experience with.
- 1) ST (as trailer tires, only),
- 2) LT (including "flotation" types, on light trucks/some offroad vehicles),
- 3) Drag-racing tires (front-runners, semi-treaded street/strip slicks, full slicks - bias ply or radial).
*1) ST trailer tires...I've used both bias-ply ST, and radial ST tires on a tandem axle trailer. And, once, with bias on one axle and radials on the other (not recommended, but worked ok). IMHO tandem axle trailers should always run ST tires, due to the ay tight turns will try to drag one of the two tires on a side into a tread-scrub situation, in which the tread is physically going sideways. ST tires are engineered (supposedly, not so sure about Chinesium tires!) to fight this, with harder tread compounds and stiffer sidewalls.
I prefer the even stiffer ST bias, if available. Axle camber is also a problem with trailers, usually tandems where the loads are variable, and the axles aren't usually equipped with shock absorbers (fewer without, nowadays); "built-in camber"ed axles flex under load, and the ST tire sidewalls must be stiff enough to control it. Single axle trailers don't have the tread-scrub problem, but if equipped with cambered axles, there's flex, also. But, since the owner/operator of a typical single axle trailer (teardrop, squaredrop, etc.) usually is cognizant of load weight and balance (let's hope), then the tires may be pressure-adjusted to fit the overall situation (much like a car mfg. makes recommendations on the pre-tested vehicle). Still, my experience of hard-driving at higher speeds makes me opt for the max cold pressure on ALL tires.
* 2) LT tires...Single axle use (front and rear truck axles, squaredrop trailer) at max cold pressure. I keep my Tow-Vehicle '04 2500HD Chevy truck pretty-heavily-loaded at all times (bed-full of camping gear, bug-out gear, car repair gear), but hardly ever drive it in between excursions. Hence, it is always ready to tow my heavy 2222 lb 4x8squaredrop (squareback), without needing to worry about tire inflation (265/75R16 tires,50 psi front, 80 psi rear. The only time I ever needed to run less than max cold pressure was in deep slushy snow (2wd truck), but I'm not sure that it helped. On my 4x8 trailer, again at max cold pressures, the stiffer sidewalls of the LT (flotation) tires reduces any flex on twisties on the highway, and the deeper tread (than on ST tires) resists sliding (as far as I can tell). Not really an improvement over the previous bias-ply ST tires, but I feel they're safer. My single -axle was ordered specifically without camber, because I built the suspension myself, to use the tires as a shock-absorbing/load-supporting component, with about 15% extra capacity (3500 lb axle/ 3000 lb springs/ 3000+ lb load-rated tires).
* 3) Drag-racing tires...Not applicable to this discussion really, but.... Front-runner tires are very thin and tall, with little load-bearing or turning ability, just there to let the car roll thru the two light beams (start-finish) that count. No wind resistance nor good for prolonged braking, either. DO NOT USE on your trailer, drag-racing only! Street-strip partially treaded drag slicks are just a DOT-approved way to run your race car on the street (and maybe slowly home on wet roads), primarily used by street-racers or guys with a $$$$$ pro-mod street car. Also, not for trailers. Full-on drag slicks, not approved for street use, but a lot of fun. The only type of tire I'll reduce air pressure in, for more traction if needed, but only because the tire beads are screwed to the rims. Not for trailers.
* ****Passenger car radials (did I forget this group??)....I use them on our small front wheel drive '08 Cobalt (205/55R16) & '09 HHR Panel (215/55R16), and on our old '98 GMC (255/60R15). Good for all weather, no towing except for the GMC (a 4500lb 20-ft travel trailer). All aired to max cold pressure!
by TimC » Thu Apr 15, 2021 12:18 pm 
