TPU tyre inserts for Tamiya Lunchbox

I wanted some inserts for my Lunchbox tyres so to reduce sidewall flex and lock the beads in place. Having a fresh roll of TPU I decided to give making some a go.

The idea is loosely inspired by airless tyre designs. I've run these and they seem to do the job. They are intentionally smaller than the inner tyre diamater to still allow some tyre squish before the tyre contacts the insert.

You'll need to included tool to get the insert onto the rims as they are very tight even after i added the segmented curves in the inner rim to make the stretch more easily. In future, I will probably design a tool to compress the in place so that the tyre can be installed/removed over the insert.

Enjoy!