im betting most of the comments here regarding hate towards the 15mm axle are from people that have never seen, let alone ridden or used a 15mm axle. it is much lighter then a 20mm, you dont have the end bolts ect. The stiffness is close to a 20mm. a larger diameter leg would make a more noticeable difference in stiffness than 15mm compared to 20mm. The simplicity of the 15mm is awesome, easier to use than a regular qr in my opinion. Im not a huge fan of this fork however, i think they needed to do more with this to call it a true dj fork, but i am a fan of the 15mm. there are lots of good options out there for hubs now. Shimano, hope, chris king, hadley, I9 ect...