If memory serves, they are 3” different, so 6” additional track width. The particular rims I have are off of a US military mine sweeper. They had hit the parking brake on the rear of my Unimog #2, so I had just run them on the front. Someone else on this forum has them on a FLU with no problems, so I am going to give it a second shot. I have 3/8” and 5/8” spacers in case I need them.What is the offset of the drum-brake rims vs the disk rims?