Thule M8 Knob with Cap

thingiverse

I was constantly replacing my rack knob because they kept breaking on me. But one day, disaster struck when yet another broke off, taking the roller with it - just like in that picture. That was all the signal I needed to give up on those flimsy knobs! These new PLA knobs are incredibly durable and come with an improved design that makes them a breeze to turn. You'll need an M8 nut, which you can salvage from your old broken knobs like I did. While the cap is not strictly necessary, it adds a nice touch and keeps the elements out.