Performance Lab
Bike Crank
Length Test
Which crank length suits you – and your performance?
Crank length affects your movement geometry on the bike, especially the joint angles at the hip and knee. Which length is right for you depends on factors such as your anatomy, riding position, mobility and the demands of your sport.
For cyclists and triathletes
Can a different crank length improve your position without compromising your performance? In triathlon in particular, changing your crank length can create more room for an aerodynamic riding position. The test examines how you respond to defined intensities with different crank lengths. This gives you a sound basis for decisions about your bike fitting and choice of equipment, so you don’t have to rely on general recommendations alone. You can book the bike fitting as an optional extra.
Procedure
How the test works
After a warm-up, different crank lengths are compared on the bike under standardised conditions. For each length, you complete two 8- to 10-minute intervals, at base endurance intensity and at your target race intensity. Oxygen uptake, muscle oxygenation, lactate, heart rate, your perceived exertion and power output are recorded throughout. The results are assessed together with the changes in your riding position and movement geometry.
Results
What you take away from the test
Oxygen uptake & ventilation
The VO₂Master measures your oxygen uptake and breathing response with the different crank lengths. At comparable power output, differences in oxygen demand can indicate changes in physiological strain.
Muscle oxygenation (SmO₂)
The Moxy Monitor records local muscle oxygenation during exercise. The data show whether and how the oxygen balance in the muscle being measured changes between settings.
Lactate & heart rate
Lactate measurements and heart rate complement the assessment of your metabolic and cardiovascular response to exercise at defined intensities.
Individual recommendation
You receive a clear side-by-side comparison of the crank lengths tested and a well-founded recommendation for your choice of equipment and riding position.