WHAT’S STOPPING PEOPLE

For ultralight bikepackers, gear made out of heavy materials costs more in weight than the items being carried affords. A guiding insight we found: the more someone invests in biking, the more consideration they give their gear and the less patience they have for wasted space and weight.

DESIGNING BASED ON MATERIAL CONSTRAINTS

I characterized different plies of Polystrand before we moved into the design phase by conducting tensile tests, cutting strips, heating, bending, and piercing the material. Bolt cutters dented it without getting through, but scissors went through each sample tested. This shifted us away from theft protection, the other direction we were considering.

LEANING INTO MATERIAL STRENGTHS

Polystrand bends easily in one direction and resists the other. Flat-pack mudguards already exploit this by staying upright when put in place. This became the foundation of the rack’s structure, acting as a rack and mudguard at the same time.

PUSHING THE DESIGN FURTHER

An idea we considered would be to add tubular metal for support. This would have worked well, but it would have become any pre-existing rack with Polystrand added to it. We pushed forward, tackling a design whose structure relied primarily on the strength of the Polystrand itself. Here, I created sketches that used rigidity of Polystrand to support the rack. These sketches were used as the foundation of our final design.

FASTENERS THAT MATCH EXISTING GEAR

Looking at existing attachments for gear and bikepacking hacks, zip ties were a quick but durable solution for the fastener. After finding a form that worked with zip ties, we wanted any hardware to be cohesive with the tools you’d find in any basic repair kit.

BUILDING THE PROTOTYPE

We iterated with laser cut cardboard to find the right look for the rear rack. Once solidified, we laser cut that design our of Polystrand. We then heated along where the rack would crease with a heat gun, and bent the material against a wooden edge. To finish, we sanded the edges and attachment holes to prevent fraying.

THE OUTCOME

PolyRack is a bikepacking rear rack that also acts as a mudguard, at nearly 30% lighter than traditional aluminum racks.