Thanks for the photo and replies. This is helpful. Sumi says a 12x148 x 180mm long with 1.75mm thread pitch will be included with a nut like you show. I was curious if Waltly cut threads into one side of the drop out so I could thread a thru axle in like on my mountain bike, but it sounds like they use the nut on the side instead. I think this should be fine but it would be really nice to have a standard thru axle size (if such a thing exists). It seems like there are 1.0mm, 1.5mm and 1.75mm threads on these rear thru axles from my research.