Home-brewed rear mech	Aggressive stance
Ultra-light Gravity calipers	S&S couplings
Carbon everywhere	Well-worn tape
Carbon cranks…	… but aluminium stem

Just to prove what can be done, Croydon-based Roberts Cycles built, for the 2004 London Cycle Show, a frame for customer Neil Carlson that formed the basis of a road bike weighing an astounding 13lbs all-up.

With recent tweaks to the component spec., Carlson has managed to get this down to 12.5lbs and, with a couple more including a radically-lightened SRAM RED rear mech about to be fitted when we visited the Roberts showroom recently, there are a few more ounces still to go.

Naturally enough, being a Roberts, the frame main tubes are steel, although the seat and chain stays are carbon. Components from such manufacturers as Schmolke, Gravity, Extralite and Tufo might be expected on such a machine, but the S&S couplings, while an invaluable fitment to a cycle that gets taken on regular trips abroad, are hardly the stuff of a weight-watcher’s dreams.

Nevertheless, the bike is not only light but eminently rideable according to the owner. And the secret of building a featherweight steel frame? ‘We weighed a whole load of lightweight tubes and chose the lightest. Some weighed 20g less than others of the same spec.’, said Chas Roberts.