Designing Functional 3D‑Printed Bicycle Pannier Adapters with Kevlar CFF

Working at an industrial‑strength 3D printing firm means you can turn an idea into a functional part in minutes. Over the past two years, our team has built everything from toothbrush holders to Kevlar door hinges and GPS mounts for bike handlebars. With the Mark Two 3D printer and a growing in‑house printer farm, the turnaround from design to prototype is astonishingly fast.

When mechanical engineer Maggie wanted a more ergonomic pannier for her office bike, she leveraged the high tensile strength of our Kevlar CFF filament and the reliability of the Mark Two to create a lightweight shoulder‑strap adapter. Panniers—waterproof bags that clip onto a bike’s front or rear wheels—are common around Markforged, but most lack a convenient way to carry them off‑bike. Maggie’s solution attaches a standard duffel‑bag shoulder strap to the pannier’s mounting clips, allowing the bag to be carried comfortably on the rider’s back.

The first prototype matched the approximate dimensions of the pannier and strap clips. While functional, the round hole was too thick and the strap clip moved awkwardly, causing discomfort when the bag was carried.

In the second iteration, Maggie reduced the clip hole size and slimmed the adapter body for a cleaner aesthetic. Using Eiger’s “Update STL” button (highlighted in red), she sliced the design and switched the filament to Kevlar, which retains more tensile strength than fiberglass or carbon fiber—critical if an overloaded bag bends the part.

The final iteration kept the geometry but adjusted the slicing settings to infill all layers with Kevlar. This produced a stronger, more durable part without increasing weight.

After printing the final adapter, Maggie assembled the bag, demonstrating a truly functional, print‑ready part that can be replicated or customized for other applications.