The idea of a fully 3D-printed frame is a myth. What is actually printed are the connection nodes, known as lugs. Using titanium powder and laser technology, the lug is built up layer by layer, precisely according to the engineer’s CAD specifications. Angles, wall thicknesses, internal reinforcement ribs—everything is executed with precision. The tubes in between are made of carbon, titanium, or aluminum; they are custom-cut and bonded in place. This tube-and-lug principle represents the current state of the art in layered frame construction. 

No mold, no limitations 

Traditional carbon monocoque manufacturing requires a custom-made mold for every frame size. This results in significant fixed costs per size. Anyone wanting to offer five sizes must invest five times as much before a single frame even exists. In contrast, those who 3D-print titanium lugs need no mold. A new size requires only a CAD modification. Atherton Bikes from Wales draws the logical conclusion: 22 standard sizes, all manufactured in their own workshop in Machynlleth. For an Asian mass-production manufacturer, this range of sizes for a single model would be financially unfeasible. Atherton simply prints new sleeves. 

Printed on Thursday, ridden on Friday 

The biggest practical advantage becomes apparent with geometry adjustments. The Atherton racing team retrieved frames from the printer on a Thursday, assembled them that same evening, and shipped them by plane to Switzerland. By Friday, the bike was ready in time for World Cup training. Traditional carbon manufacturing requires months for comparable geometry adjustments. Not because engineers work slowly, but because every change requires a new mold. The mold is the bottleneck. The Swiss company Gamux uses a similar method to manufacture its downhill bike: CNC-milled aluminum junctions instead of printed sleeves, with carbon tubes bonded in place. Not 3D printing in the strict sense, but the same logic: no mold, no minimum order quantity, full freedom of geometry. 

300 frames, no more

Anyone expecting these manufacturers to replace carbon series production from Asia is expecting too much. Atherton Bikes produces around 300 frames per year. A printing system costs up to $700,000. More frames here means above all: more machines, more money. Anyone who wants to increase production volume buys another printer—and pays the same amount all over again. Frameworks Bicycles shows just how quickly a strong concept can fail due to mass production. In 2024, downhill pro Neko Mulally tested a bonded aluminum prototype: lugs milled from solid stock, tubes bonded in place, 300 grams lighter than the welded production frame. The idea worked, but it wasn’t ready for mass production. The 2026 production frames are made in Taiwan using conventional welding.

The tube-and-lug principle does not solve any mass-production problems. However, it offers a solution for small-batch production: How can a manufacturer produce many sizes, short development cycles, and custom geometries without incurring fixed costs that multiply the frame price? It provides the clearest answer to this question to date.