Tire Selection Some good information regarding trailer tires

[ModMech]

I have seen a great number of posts and questions regarding the "need" to use "ST" type tires on trailers, sometimes it is made as a "service suggestion". While looking for new front tires for our tractor, I stumbled upon some reference materials that might help clarify the discussion of "ST" or not to "ST", as it applies to trailer tires.

Some of the take-aways from the articles linked below, regarding "ST" tires are:
1) ST and LT tires are BOTH considered acceptable for use on utility trailers
2) ST tires should be replaced every 3-5 years, WEAR is not to be used as the primary consideration (that is, just because it has good tread does not mean it is still good)
3) Almost all ST tires have a MAXIMUM speed of 65 MPH and some states enforce it!
4) In states were "P-metric" tires are allowed for use on trailers, the tire's rated capacity is to be reduced by 9%
5) Specialty trailer tires have stiffer sidewalls to help reduce trailer sway and it works

The pages linked below do not universally agree, but after reading them, I am convinced that for trailers seeing "extra-neighborhood" service, ST/LT tires are the only safe option.

Helpful Links, sources of above:
Pardon Our Interruption
Tire Tech Information - Trailer Tires vs. Passenger Vehicle Tires
Rolling Along Safely: A Tire Guide

 

[Sprinklerman]

Look at recapped airplane tires .

 

[Texasmark]

I am convinced special trailer tires are built with more plasticizers in the rubber compound which reduces cracking that is aggravated by long periods of inactivity.

 

[Citydude]

Heat is a tires worst enemy. St tires are made with a harder rubber compound on the sidewalls and face for scuffing and support. The harder compounds do not deflect heat as the LT tires do. That's the reason for the 65mph requirement. For tractor tires, I'd go with the ST's.