We have the same setup as Ahab. Strangely, the size/pressure placard on the trailer specifies ST215/75-15 load range C! Seemed too low a load margin for me. After reading the endless threads about troublesome GYMs, I went with the slight upgrade to 225/75-15 load range D when we brought it out of four years storage.
It's my first single axle TT, and apart from the quicker pivot when backing, it hasn't been worrisome at all.
2014 Flying Cloud 23FB
2009 BMW X5 Diesel