What part number did you order for spare hub/bearing/cap/nut from Knott? I just got a pair of the single/doubles and want to have some spare parts since it looks like it's going to be hard to find stuff soon. Also, if anyone could send me some photos of how the rear of the trailer couples together I would really appreciate it. I'm going to have to fabricate the part myself. I was able to find the front part of the system but I can't find the rear coupler anywhere. Thanks!