Chains were tested before and after cyclocross racing to determine the effects of a dirty chain on efficiency.
Part 1: The average increase in friction from pre-race to post-race for 2 cyclocross races was 2.07 watts. The pre-race average friction was 6.33 watts. The post-race average friction was 8.4 watts.
Part 2: The average post-race friction level of a second set of three sample chains used for 5 cyclocross races was 10.37 watts.
Part 3: The average chain friction of all six samples decreased 2.96 watts due to post- race cleaning and relubing. Average post-race friction, prior to cleaning and relubing, was 9.39 watts. After cleaning and lubing, the average friction was 6.43 watts.