British boutique steel frame brands – like Starling – are the least likely, to produce carbon-fibre models. That’s the perception, right?

And few come with more authentic British ‘built-in-shed’ legacy than Starling. The company that popularised long-travel single-pivot steel gravity bikes has revealed a prototype that looks familiar, but is very different.

This particular Starling goes way beyond the traditional material and configuration that Starling is famous for. Its front triangle is composite, instead of steel. And anchoring the frame, is a mid-drive motor (although the battery is not pictured and gets slung under the down tube on this prototype).

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A return to carbon?

For Starling founder Joe McEwan, it’s a case of coming full circle.

Before he welded those first Starling frames in his shed, Joe worked with composites in aviation. And in partnership with the UK’s National Composites Centre, he’s taken the proven geometry and suspension design of his Starling dual-suspension platform and given it a composite makeover.

Joe’s history with the NCC delivered an opportunity to build this prototype Starling. And it uses a composite structure that’s quite different from regulation mountain bike carbon-fibre.

Is this Starling frame – made from the ‘better’ MTB composite?

The tubes are braided thermoplastic, made from nylon and carbon-fibre. This method significantly reduces the need for traditional epoxy bonding – which is where much of the toxicity in carbon-fibre source manufacturing originates,

Too much epoxy also deadens the dynamic properties of carbon-fibre, reducing the material’s benefits for a mountain bike frame.

Durability is another aspect where thermoplastic tubing could prove superior to many conventional carbon-fibre structures. Thermoplastic has better impact protection than epoxy-bonded carbon-fibre, and can be repaired with much greater ease.

Not perfect – but a great first attempt

Is this half-composite e-bike going into production? Not quite. The lug technology isn’t exactly where Joe wants it to be, making this prototype a one-off. For now.

But the potential of a thermoplastic frame, still using a traditional steel rear end, is clear. As more pressure builds in the mountain bike industry regarding source material greenwashing and recycling fallacies, thermoplastic could become the choice composite – in future.