LightSpray: On Running's Sprayed-On Upper
In brief: LightSpray is a manufacturing technology from the Swiss brand On that creates a running shoe upper by spraying one continuous filament, around 1.5 kilometres long, in a helix pattern directly onto the midsole. A robotic arm builds the entire upper in roughly three minutes, with no glue, no stitching and no separate pieces to cut and assemble. The result is an ultralight one-piece upper of about 30 grams that On says cuts the carbon footprint of the upper by around 75 percent. It debuted on the Cloudboom Strike LS race shoe and has since reached the Cloudmonster Hyper.
What is LightSpray?
LightSpray is a patented manufacturing process developed by On, the Swiss performance running brand. Instead of cutting, layering and gluing the twenty to thirty separate pieces that make up a conventional shoe upper, LightSpray builds the upper in one go by spraying a single continuous thermoplastic filament directly onto the midsole. A robotic arm guides a nozzle that lays roughly 1.5 kilometres of filament in a precise helix pattern, and the filament fuses to itself as it is applied. The whole upper takes shape in about three minutes, with no glue and no stitching. It is one of the most radical changes to how a running shoe is made in decades, and On positions it as both a performance and a sustainability breakthrough.
How a LightSpray upper is made
The process starts with the midsole and last mounted on a robotic arm. A nozzle then sprays a single hot filament onto the form, moving in a controlled spiral so the strands bond to each other and to the midsole as they cool. Because the upper is sprayed straight onto the sole unit, there is no separate bonding or assembly step, and there is no offcut waste from cutting flat panels. On has said a complete shoe can be produced in around six minutes once the sole is ready, compared with the much longer, multi-stage assembly of a traditional running shoe. The density and placement of the filament can be tuned to add support where a runner needs it and openness where breathability matters.
How light is a LightSpray shoe?
The headline benefit is weight. A LightSpray upper weighs about 30 grams, which is a fraction of a conventional layered-and-glued upper. By collapsing the twenty to thirty pieces of a normal upper into one sprayed structure, On removes the overlapping materials, glues and stitching that all add grams. On its Cloudboom Strike LS race shoe, that helped create one of the lightest carbon-plated racers the brand has made. Less weight on the foot is one of the simplest ways to make a fast shoe feel faster over a marathon.
Is LightSpray more sustainable?
On frames LightSpray as a cleaner way to build a shoe as well as a lighter one. Because the upper is a single material sprayed with no glue and no cutting waste, On says it reduces the carbon emissions of the upper by around 75 percent compared with a traditional upper. A one-material, glue-free construction is also easier to handle at end of life than a shoe made from many bonded materials, which supports recycling ambitions. The robotic, on-demand nature of the process also points toward more local, made-to-order manufacturing with less transport and less overproduction.
Which On shoes use LightSpray?
LightSpray made its debut on the Cloudboom Strike LS, a limited-release carbon-plated racing shoe that On unveiled around the 2024 race season and put on the feet of its elite marathon athletes. Since that launch the technology has been extended beyond pure racing, appearing on the Cloudmonster Hyper, a more cushioned everyday model. Availability has been deliberately limited while On scales the process, so LightSpray shoes have tended to arrive in small drops rather than mass release.
LightSpray at OD's Designer Clothing
At OD's Designer Clothing we are long-standing stockists of On, carrying its Cloud running and lifestyle range across our St Helens store and website. LightSpray sits at the cutting edge of what On is doing, and while the sprayed-upper models are released in limited numbers, the same brand engineering runs through the wider Cloud line-up we stock. We offer next-day delivery and free click and collect, and customers in the North West are welcome to try On's shoes in person in store.