It looks like a lot of manufacturers are indeed increasing their speed ratings in the past few years. However, that does not mean that it isn't true. Tell you what..... drive down to your local RV store and look at the speed ratings on some of the tires on their fifth wheels (or travel trailers). You'll see what I mean.
There's no misinformation here. I've been towing fifth wheels for the better part of a decade, have gone through the same issues as every other rv'er. More than likely there are quite a few in here that know exactly what I am talking about.
Comparing ST and LT Tires: Understanding the Variances Special Trailer (ST) tires are purpose-built for trailer axle applications, catering to the specific demands of towing without consideration for passenger comfort. Unlike Light Truck (LT) tires, ST tires are engineered to endure heavy loads...
venturetrailers.com
"Tires on boat trailers have to be ST tires which stands for Special Tire. ST tires are designed specifically for boat, car and utility trailers. They are built to carry heavy loads on non-powered
axles and are rated for a maximum speed of 65mph. Their stiff sidewalls help prevent your boat/trailer towing package from swaying. All ST tires feature materials and construction designed to meet the higher load requirements and demands trailer towing presents. ST tires have some of the highest load ratings. This is one of the reasons they are designated for use on trailers. Truck and automobile tires do not have to withstand the weight and stress that is put on trailer tires."
Special trailer tires have a maximum speed rating, just like passenger car and truck tires.
Older tires have no special marking to designate a limit. Their maximum speed is 65 mph. Newer tires, those manufactured in 2015 and later, should have one of the following codes on the sidewall to show their rating:
(Note that I DID say that they may have changed that rating since I last had one...)
"Point of clarification. The Tire and Rim Association load formula used b
y the industry for ST-type tires is based on a 65 mph max operating speed. They even identified inflation increase and load capability reductions necessary to operate up to 75 mph. Neither P- nor LT-type tires have stated max speed associated with their load formula or calculation, as far as I can find. P-type do have the stated 1.10 “derating” of load capacity when used on a trailer or pickup."
RV Tire Safety with RV tire expert Roger Marble Point of clarification. The Tire and Rim Association load formula used by the industry for ST-type tires is
www.rvtravel.com
Hope this helps.