I bought a second hand wheel which has a DT Swiss 370 hub. I miss-thought the hub is for a 135x9 mm axle, but it is not. After finding out that it was not a 9 mm I took a deeper look to the hub and found something that surprised me, the hub ends in a male thread.
I was not able to find the user manual... So my questions are:
Does this hub need a 135x10 axle?
What is that male thread for (see images)?, is it supposed to rest on the frame directly?
Outside of the hub, the DT 370 rear axle looks like this:
135x10, 135x10 QR, or just 135 QR, would all be accurate ways of describing the axle standard as far as frame compatibility is concerned. What can be confusing is "135x10 axle" could be taken as referring to a standard repair axle of given dimensions (in this case 146mm long with M10x1 threads) that a common cup and cone hub would use, like what a typical Shimano or OEM brand mountain/hybrid/etc hub would want if its axle got stripped or broken. Your 370, like most fancy cartridge bearing hubs, takes a specific proprietary axle with shoulders, flat machined spots, etc.
The stub of external thread is what the axle hardware threads on to, what you use to adjust the bearings, etc. It does in fact contact the frame. This can be counterintuitive, but the other counterintuitive thing is the very high amount of clamping force provided by the QR skewer. As long as it's clamped down adequately, that connection is keeping the axle from rubbing against the frame in a way that could damage anything.
Also, 9mm is associated with QR front hubs, not rears.
