Barbara:
We have a 2017 Cyclone CY3611JS. 40' long front to end cap. 17,000# gross, with Dexter 7,000# axles.
I'm considering upgrading to 8K axles, springs, and accessories.
When I look through Dexter axles, the 8K axles, the hub face to hub face (HF) dimensions are wider than the 7K stock...