SOME lightweight bicycle wheels have a design flaw that makes them shatter
dramatically. 鈥淚 had a guy come in who鈥檇 had his wheel on the kitchen table and
it exploded in his face while he was inspecting it,鈥� says John Morgan of Bristol
University, who has been studying aluminium wheel rims. 鈥淗e got aluminium in his
eyes鈥攈e was lucky not to lose his sight.鈥�
Morgan told a meeting of the British Institute of Physics this week that the
problem happens when wheel rims are reinforced by a single aluminium section
that runs round the inside of the wheel. As brake blocks wear down the rim, he
says, cracks develop near the reinforcement and the wheel shatters. 鈥淭hey simply
explode鈥攜ou get the whole side of the rim peeling off,鈥� Morgan says.