I have never heard of Hybrid axles but I don't see where it says the tubes are 3" rather than 3&1/2, but it does appear that those axles use 2" brakes, maybe this trailer is full of shortcuts, guess I won't know until I get it and put it to use, hopefully since the axles are rated for 8k they will stand up to the 11k that I am going to be hauling on the trailer, they told me that the payload on the trailer was 13,300 pounds.Be advised, Kaufman uses some hybrid 8k axles with 3" tube and 2" brakes. You might want to confirm, if in doubt. Standard 8k is 3.5" tube and 3 3/8" brakes.
8k Electric Brake Axles - Kaufman Trailer Parts
12"x2" Electric Brake Assembly - Kaufman Trailer Parts
I would like for it to be as heavy duty as possible as it will mainly be hauling my skidsteer with forestry mower attached, so around 11k, I have been hauling it on a 20' equipment trailer with 2- 7k axles and it has worked but it is overloaded, roads around here are so bad with pot holes that I have put a slight bend in both of these axles on the passenger side of the trailer. I really wanted a gooseneck but I just can't get it in most of the places that I go, but the bumper pull will follow the truck so much better in tight driveways.Not saying Kaufman uses these but just an example, they are out there. With your use, it might not even mater to you. Getting the 17.5's is a big plus.
For my use, I want the big axles and brakes.
8k Sprung Lippert Hybrid Trailer Axle - 8000 lb Electric Brake 8 lug (12" x 2" Brake - 3" Tube) | Axles | The Trailer Parts Outlet
Be advised, Kaufman uses some hybrid 8k axles with 3" tube and 2" brakes. You might want to confirm, if in doubt. Standard 8k is 3.5" tube and 3 3/8" brakes.
8k Electric Brake Axles - Kaufman Trailer Parts
12"x2" Electric Brake Assembly - Kaufman Trailer Parts