There are Kumho trailer tires on the market that are being reported as durable and with a 75 MPH speed rating. They come in three 14” sizes, all load range
D. They are of European design and the
C after their size indicates their basic design is commercial.
Here is a reference with all the particulars.
http://www.kumhousa.com/tire/categor...E-E59335DE416C
CW