Are stiffer frames always faster?

Stiffer, lighter, faster! It seems nearly every newly-launched race bike aims for the superlative in all three of this holy trinity. Weight is easily quantifiable, aerodynamics ditto – but stiffness is more difficult to assess.

Instead, we tend to read about frames that are ‘15 per cent stiffer’ than the previous model, or ‘as stiff as the last model, but lighter – so stiffness-to-weight is improved’. These more woolly claims are largely used because different brands have their own methods of testing stiffness, and a bit like the ‘mine goes to 11’ method of indexing shoe stiffness, the scales aren’t comparable.

THE NUMBERS DON’T COMPARE

Stiffness tests, in general, are completed by hanging weights from a frame and measuring flexion in millimetres. There are industry standard tests, which frames have to pass. There are standard testing rigs – such as those from Zedler, and it’s