The Sailun in question are ST trailer tires and has nothing to do with motorhome fitment.
Thanks Philly for the tip....
I use the Sailun S637 on my 16k GN triaxle stock trailer for several reasons . One being my and other family safety out on our hiways. The S637 ST have been around since the '10/'11 era mostly in the commercial service trailer industry and the last few years many have found out their a excellent tire for heavy rv trailers with 7k-8k axles.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 two slides