Can I add a subsequent, related question?
Are all rear mtb skewers actually the same length?
The reason I ask is that I use a trailer on the mtb and the hitch is a fairly substantial piece of cast Al almost 5mm thick, which slots onto the QR skewer outside the forks. This means that there's not as much thread holding the nut on the skewer as I would like so a skewer an extra 5mm or so longer than typical would at least make me feel safer