A Kryptolok Combo U-Lock holder made to fit on top of the Axiom Streamliner bicycle rack. 

I made this mount my U-lock on the back of my bicycle where I have an Axiom Streamliner rack. This 3 piece holder fits over the rack and u-lock to hold it in place in the center of the bike when riding so the lock does not hang off one side of the bike or drag the pannier bags. 

Print all 3 pieces in high shore hardness TPU. I recommend a hardness of at least 95. 

The larger piece attaches the thicker lock tube to the front of the rack. The two smaller pieces attach the curved end of the lock to the rear of the rack.