I've had experiences good and bad with Harley Davidson dealers when out on extended road trips and needing parts or service on my HD. Sounds like you learned a valuable lesson when it comes to leaving on a trip with anything other than new or almost new tires.
If it's any consultation even all but the wealthiest Harley riders refer to the dealership as "The Stealer" and like me do my own work and tire changes or seek out good independent shops.
Gotta say......being out on the road and needing help sure leaves you at the mercy of the helper! Been there done that.
New Mexico, not really new, not really Mexico.