Wow that is a huge decrease in range while towing, more than some TMC members report when towing a 22 ft Airstream. I think the explanation is that your Go Trailer in utility mode with a kayak on top creates far less aerodynamically efficient than an Airstream or similar trailer.
@bonnie how much of a range decrease do you get in your X when towing your Go Trailer as shown in your photo?I just got back from a beach trip pulling a Go Trailer at 45 to 60 mph. I had closer to 70% hit, but my trailer was in utility mode (jacked up above MX roofline) with 4 bikes inside, a kayak on top, coolers, gear, etc. I should add that it was a .7 additional mile for every Tesla estimated mile. To know the actual decrease in efficiency, I would have had to do the same route in same conditions at same speeds without the trailer. At some point I intend to do a bunch of experiments with Go trailer over a shorter distance. My bottom line from my trip was with a MX90D I could get about 140 miles before needing to charge again with my trailer loaded the way it was.