Oh, sorry. The short threaded end is on the left side of the swing arm. When you insert the axle like this it becomes obvious that is how it goes in and I believe is correct application. If you just put the axle up to the swing arm (on the outside of swing arm, not installed) it looks like it could go in either way. When everything is installed, both sides of the axle have the exact amount of thread showing behind nut when torqued down to 83nb per work shop manual. At least this is what I found out. The Ducati work shop manual did not say which end is which, just said take it out and put it back in with no reference to short and long threads going on which side of swing arm. Go figure.