Model originally uploaded to Thingiverse at https://www.thingiverse.com/thing:5159255.

I removed the training wheels from my sons bike, and found these bolts stuck out too far for my comfort. I designed this to fit over the bolt and have flaps that bent slightly but held on tight to the threads. Designed for .28 layer height with three layers for the bottom piece. Printed with a 20% infill, but if it breaks I will reprint and increase.