Chain Ring / Chainguard Cover for Kubikes 24" Kids Bike

A replacement for the plastic chainring guard that cracked off my kid's KUbikes 24" bike. It's the cone-shaped ring that bolts over the chainring with 5 screws and keeps fingers, laces and clothing away from the chain.

Fully parametric OpenSCAD model, measured directly from the broken original, so you can reprint an exact replacement or tweak any dimension for a similar guard on another bike.

Two variants included

Original — same wall thickness and tab dimensions as the factory part (2.3 mm ring wall, 1.6 mm outer edge, 5 mm tabs). Faithful reprint if you just need a drop-in replacement.

Robust — thicker ring wall (3.2 mm), thicker outer edge, wider tabs with reinforcing gussets where the tabs meet the ring — exactly the spot where the original snapped. Same outer dimensions and chain clearance, so it still fits, just tougher. Recommended if the first one didn't survive long.

Switch between them with a single variant parameter at the top of the .scad file.

Fit

- Outer Ø145 mm / inner Ø110 mm ring, 5 mounting tabs

- Bolt circle Ø90 mm (5 holes, hex-recessed for the captive nuts, hole Ø4.1 mm for M4 screws)

- Cone rises 5.6 mm from inner edge to outer edge for chain clearance

Measured on my own Kubikes 24"; hardware and chainring covers can differ slightly between model years, so check the numbers against your bike (or print the flat 1:1 paper template included below) before committing to a full print.

Disclaimer: modelled with Claude Fable, fit verified with a test print.