This section explains how the wheels are built and how we satisfy ourselves that they are sound — rather than what they cost or how they look.

Spokes are the clearest case of a component that is easy to market and harder to explain. Carbon and steel spokes behave differently under load: a carbon spoke is lighter for a given stiffness and does not fatigue the way a metal spoke does, but it needs its own spoke hole and nipple interface, and a steel spoke such as a Sapim CX-Ray remains the benchmark for serviceability in many builds. The spoke-hole and pull test write-up shows what happens at the rim bed and at the spoke itself once load goes beyond anything a wheel should meet, carbon vs steel spokes sets out where each type genuinely differs on the road, and spokes on a bike explained covers how a wheel carries load at all.

Structural testing is the other half. A rim can fail in several different ways, and the tests that matter are the ones that reproduce them: a spoke hole pulling through the rim bed, a rim taking an impact at the edge, a wheel surviving a hit that would otherwise leave you walking home. We publish our impact test results and explain what those tests do and do not prove — including the fixtures used — so you can judge the method rather than only the headline figure. Where a wheel has been assessed against a recognised standard, we say so.

Materials sit underneath all of it. Carbon layup, resin system and rim finish determine how a rim behaves at the spoke bed and at the bead hook, and they explain why two rims of the same depth can weigh and ride quite differently. We do not yet publish a dedicated piece on rim manufacturing; when we do, it will live here rather than being folded into a buying guide.

Hub internals get less attention than rims and probably deserve more. Ratchet design, bearing specification and axle construction decide how a wheel engages under load and how it holds up across seasons of wet riding. For the practical side — bearing care and what wear actually looks like — see the maintenance guides in Setup & Compatibility.