It was the use of steel which allowed velocipedes to develop from agricultural cart technology into the high-wheel ‘penny-farthing’. Steel frames, steel rims hubs and spokes, steel cranks. Saddles were leather, of course, tyres solid rubber until Dunlop introduced riders of safety cycles to the comfort (and better rolling performance) of his pneumatic tyres. Smaller details were fashioned from brass or bronze. No aluminium anywhere – in fact it wasn’t until 1889 that Bayer developed a commercially viable process to extract Aluminium from bauxite. The story of bicycle components through the 20th. century illustrates the way this new, exotic lightweight but weak metal was developed to its full potential.

1909 Duralumin Developed by Dürener Metallwerke, Germany. 4% Cu

UTS 150-450 MPa so 3 to 9 times stronger than pure aluminium, as strong as mild steel in its more advanced tempers

Dural was first used to build the frames of Zeppelin airships during WW1.

1927 Conloy alloy. Imported components – cranks, chainwheels, hubs, pedals, toeclips (all these were only marketed for a couple of years), and rims which proved very successful so were marketed for maybe 3 decades. The composition and strength of this alloy are a mystery to me but Conloy rims have proved durable enough to survive well today.

After WW1 Dural was soon being applied to bicycle construction – as early as 1929 Carpenter was offering proprietary Duralumin hubs, in 1934 Magne won the Tour de France using Dural Fiamme rims (disguised as wood to avoid rejection) by 1936 Caminargent frames had octagonal alloy tubes bolted into lugs, TA and Williams were offering Dural chainrings. But Dural had a reputation for failing, so critical components like cranks and handlebar stems continued to be made from steel.

1929 RR ’50’alloys. Developed by Rolls-Royce, Cu 2%, Fe 1.4, Ni 1.3, Mg 0.8, Si 0.7

UTS400 MPa, as the best Dural strength, but forgeable and temperature resistant.

Developed by Rolls Royce to withstand the high temperatures of race-car and aero engines, RR56 was used in the RR piston engine of the Supermarine S6 which won the Schneider Trophy outright in 1929 and became a prototype for the Spitfire. Thousands of RR Merlin engines were fitted to this plane, the Hurricane, the Lancaster and the USAF’s Mustang fighters. After WW2 Reynolds subsidiary High Duty Alloys Ltd. found much greater acceptance of this alloy (now branded ‘Hiduminium’) for critical bicycle components like handlebar stems and brakes. Gerry Burgess (GB) was supplied with forgings as he introduced his range; eventually even Williams belatedly adopted alloy cranks for their AB77 cotterless chainsets.

Post Carpenter

1970s ‘Ergal’ 7075. Developed 1935 by Sumitomo Metals. Cu 1.5%, Mg 2.3, Zn 5.9.

UTS 400 MPa

Developed for the airframes of Mitsubishi Zero fighters of WW2.

Used by Fiamme for rims in the 1970s (it proved somewhat brittle at the spoke holes).