Coaching Tips - Crank Size
Is a compact crank right for you?
By NRG Coach Sylvie Dansereau
Now that we have discussed the advantage of riding at higher cadences (~85-95 rpms) as well as developing your ability to ride economically at a wide range of cadences through your training, I should touch on the equipment aspects of this.
A compact crank is a crank (your rings at the front of your drivetrain) that has smaller rings than your ‘standard’ crank. What we refer to as a compact crank is also called a 50/34, which means it has 50 teeth on the large ring and 34 teeth on the smaller inside ring. To compare this to a ‘standard’ (53/39) crank where the bigger ring/harder gear has more cogs with 53 and the smaller/easier ring has 39 cogs. The smaller the rings (with lower number of cogs) on your crank means that it allows the athlete to use a more optimal/higher cadence at lower speeds seen in uphills than with a bigger crank where athletes are stuck mashing at slow cadence to make it up the moderate to steeper inclines.
A compact crank is better suited for almost all non drafting endurance athletes considering the speeds that these athletes routinely train and race at. For example with a compact crank (50/34) and a 11-27 rear cassette, an athlete would be able to pedal at speeds of about 55 kph (so plenty fast enough!) in their hardest gear (50X11) at cadence 95, while being able to retain a reasonable cadence (85 rpm) in hills for speeds as low as 13.5 kph (and obviously can go slower by dropping cadence as needed from there) when using their smallest gear (34X27 in this example).
Only in very rare cases, would an amateur endurance athlete require harder gears than this. These individuals could consider a ‘mid compact’ crank (52/36) which will allow a little more speed in their hardest gear whilst still allowing reasonable cadences at lower speeds seen in climbs.
Something to keep in mind when making equipment decisions for your training and racing
Sylvie
