Jayco builds trailers. Jayco buys tires. I prefer to listen to the tire manufacturers who build the tires that Jayco buys. I run all my trailer tires at max sidewall pressure as the tire manufacturers recommend.
Some info copied from another thread. It includes some references for those who want more information.
Per standards Special Trailer tires are speed rated to 65 mph, not 60 mph. Sorry to be a broken record, but anyone who runs their trailer tires at too low a pressure may be setting themselves up for tire failure and even handling problems. You don't need to listen to me, you can research what the experts recommend in the links below.
A Canned Response
Most special trailer tires are speed rated to 65 mph. Speed rated is not speed limited. Tire pressure can affect the speed range. Too little tire pressure is a greater sin than too much pressure. Consult your tire manufacturer information.
Personally I would not run my trailer tires at less than the max rated pressure listed on the sidewall. In my experience that mode gives good wear and puts the tire in a range for higher speeds.
Below is some specific information for
Goodyear Marathon Tires
Special Trailer ("ST") Tires
Goodyear Marathon trailer tires are widely used in a variety of towable trailer applications and are designed and branded as "ST" (Special Trailer) tires.
• Industry standards dictate that tires with the ST designation are speed rated at 65 MPH (104 km/h) under normal inflation and load conditions.
• Based on these industry standards , if tires with the ST designation are used at speeds between 66 and 75 mph (106 km/h and 121 km/h), it is necessary to increase the cold inflation pressure by 10 psi (69 kPa) above the recommended pressure for the rated maximum load .
o Increasing the inflation pressure by 10 psi (69 kPa) does not provide any additional load carrying capacity.
o Do not exceed the maximum pressure for the wheel.
o If the maximum pressure for the wheel prohibits the increase of air pressure, then the maximum speed must be restricted to 65 mph (104 km/h).
o The cold inflation pressure must not exceed 10 psi (69 kPa) beyond the inflation specified for the maximum load of the tire.
More info is here:
If the link doesn't work then just add www. to this
What Carlisle says:
Underinflation is the number one cause of trailer tire failure. Low
inflation pressure elevates tread temperature, especially as speed
Review - Practices for Safe Trailer Tire Use
– Maintain air pressure at the maximum PSI recommended on the
What etrailer says:
Trailer tires should ALWAYS be inflated to the maximum psi rating as indicated on the tire without exception. The reason is that if under inflated, because trailer tires are built with a thicker side wall to handle more vertical load, a lower pressure will cause excessive heat build up and cause the tire to fail.
Maximum Air Pressure for the Wheel in the Trailer Tire and Wheel Combo # TW15BIAS5ON475 | etrailer.com