An Australian publication, Ride Magazine posted results of a test for crankset stiffness. The test was performed using a jig and 40 kg weight. The flex was measured for each crankset and the results were:
1 ) Shimano Ultegra 2.08mm
2 ) Time ASX Titan Carbon 2.12mm
3 ) Shimano Dura Ace 2.20mm
4 ) Campy Chorus Carbon CT 2.48mm
5 ) Campy Record Carbon 2.59mm
6 ) Campy Chorus Aluminium 2.62mm
7 ) Campy Centaur Carbon CT 2.76mm
8 ) Campy Record Aluminium 2.78mm
9 ) Campy Centaur Aluminium 2.99mm
10 ) FSA Gossamer Megaexo 3.05mm
11 ) Zipp 300 3.40mm
12 ) FSA SLK Megaexo 3.41mm
13 ) FSA K-Force 3.76mm
Other considerations like weight and cost as well as a flex test using a 20 kg weight were factored into the total score that I posted previously, but I felt this was confusing and misleading. I wasn't surprised to see Ultegra and Chorus were stiffer than DA and Record given the added weight, but I was surprised to see FSA's top models being more flexy than Centaur. I have heard some nice things about the new Ultegra 10 groupset, and this test certainly backs up some of the claims.