The rear axle acts like a quick release but it threads into the frame on the drive side. The distance between dropouts is 170mm, but I guess you'd need a bit longer for the threads so probably is 177x12. I have the same setup on my Fuel EX, except that rear axle is 142x12. From what I can find online, most wheels use a standard QR hub, or a TA for a 190mm hub.