The original design was pretty decent but no good for really long term use as I discovered when one of the hinge points snapped. I've designed it again from ground up using original dimensions but this collar is 20mm thick with a 4mm clearance at the back of wheel, the hinge points are much thicker with a wider paddle stop.

This design calls for M3 bolts 40mm with self locking nuts with washers as this will take tightening this up LOTS so it never slips. Its way more robust than before, I've reused the original paddles however as these are spot on.

• Edit * I forgot to say I'm using round rubber pads (4mm thick) on the paddle notch that goes against the wheel buttons, it helps keep a better constant contact and also dampens the sound. It was already in my photos but just wanted to actually point it out :)