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We Sent Our Bamboo to a University Lab — Here's What the Numbers Said

Magnified bamboo cross-section with a red arrow pointing to the dense fibre bundles near the outer wall
Magnified bamboo cross-section with a red arrow pointing to the dense fibre bundles near the outer wall

People often ask the same question before they build with bamboo: will it actually hold up? So we did the obvious thing — we sent our bamboo to an engineering lab and had it tested to a recognised international standard.

Context

Bamboo is a naturally occurring composite: longitudinal cellulose fibres set in a lignin matrix, with fibre density increasing toward the outer wall of the culm. That structure is what gives it a high strength-to-weight ratio and the natural vibration damping that makes a bamboo frame so comfortable to ride. But "naturally occurring" means every culm is slightly different — so the only honest way to talk about strength is to measure it.

Cross-section of a bamboo culm wall, with an arrow showing fibre density increasing towards the outer surface
Fibre density increases towards the outer wall of the culm.

What we did

In partnership with Swansea University, bamboo culms supplied by Bamboo Bicycle Club were tested to BS ISO 22157:2019 — the international standard for determining the physical and mechanical properties of bamboo.

  • 14 culms were sent (labelled A–N); the 6 highest-quality specimens were selected for testing.
  • Flexural (three-point bending): load applied at a node over a 300 mm span.
  • Tensile: 180 × 8 × 3 mm specimens with epoxy-attached tabs, pulled at 2 mm/min.
  • Compressive: tested per the same ISO standard.

The results

Test Property Result
Flexural Young's modulus (average) 6,402.93 MPa
Flexural Ultimate flexural stress (average) 70.96 MPa
Tensile Ultimate tensile stress (average) 84.34 MPa
Compressive Ultimate compressive stress (average) 57.7 MPa
Graph of force against displacement for six bamboo specimens in three-point bending
Three-point bending: force against displacement for six specimens.
Graph of tensile stress against strain for six bamboo samples
Tensile tests: stress against strain for six samples.
Graph of force against displacement for two bamboo specimens in compression
Compression tests: force against displacement.

The bamboo showed little to no plastic deformation — it carries load and then fails cleanly once the maximum bending moment is reached, rather than slowly bending out of shape. Results varied between specimens, exactly as you'd expect from a natural material with differing diameters, wall thicknesses and natural defects.

In plain terms: tested to an ISO standard, this bamboo is comparable to mild steel in strength — while weighing a fraction as much. That weight advantage is the whole point of building a frame from it.

Why it matters

This isn't a marketing claim — it's a measurement, taken in a university lab to a published international standard. It's worth being precise about what it covers: Swansea tested our bamboo tubing, not a finished frame. How a frame performs also depends on its joints and on how carefully it is built — which is why every kit comes with step-by-step instructions and support from our team.

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