We just finished a 14,700 mi 10 week trip from Alaska to Florida and back, with many side trips in between. Pulled a 43ft triple axle TH.
As far as 3 axles go, I liked the added weight distribution, the trires do scrub a bit a low speed maneuvering turns. Just DON'T look in the mirror at the tires, it will frighten you how much they deform. But, not one single tire problem over those 14,700 miles. Rear tires seemed to wear a bit more than the rest, but barely noticeable. I carried the Maxxis ST 16" E rated and was very satisfied.
Turns tighter, but just pay attention and it isn't that big of a problem. I only snagged one curb the entire trip and that was from a bad choice of roads with absolutely not enough room to avoid the curb.
My biggest piece of advise is make sure you tow with a fifth wheel hitch and not a goose neck adaptor. We bought the TH used, (our first RV) and the previous owner had used the GN adaptor. Major frame stress problems we had to get fixed halfway through the trip.(Lippert frame by the way, just saying)
Re the shackles - REPLACE them as soon as you can, preferably with the heavy duty 1/2" greasable versions. We had the standard shackles and replaced those about 12,000 miles into the trip. Normal wear and tear, but go with the heavy duty for longer wear and peace of mind. It's cheap insurance.
TV is a 2013 F450, pulled like a dream. Triple axle TH tracked behind it like it wasn't even there. One benefit to the f450 was BRAKING. We had an intermittent wiring problem for a short while that caused the trailer brakes to not work reliably. Very nearly couldn't tell the trailer wasn't braking unless I used just the break controller to see if it would tug back on the truck.
