What Is Cadence and How Do I Calculate It?

John March 4, 2009 1

If you are ever talking to an avid cyclist, you may hear them mention something called cadence…what the heck is cadence?  Well, when people talk about cadence they are referring to the number of revolutions the crank makes each minute as the pedals are being turned…basically this is the speed at which you pedal as you are riding.  Many people prefer a certain cadence at which they like to ride…and since many bikes have tons of gears, it makes it possible to always stick to a certain cadence…but not for us…we only have one gear.  Cadence is measured in rpm’s (revolutions per minute).  A normal cadence is usually between 60 and 80 rpm’s…although this number can vary, depending on what kind of riding you are doing.  Some people have been known to top out around 170 rmp’s. But anyways, as you can probably guess, there are specific cadence computers you can buy for your bike that will tell you this information easily and accurately; but if you just have a normal bike computer that tells your speed, there is a formula that will determine your cadence, you’ll just have to know a few things about your bike…I found this on bikeforums.

What you need to know:
– Chainwheel Tooth count
– Rear Cog Tooth Count
– Speed (current or average)
– A magic number (that corresponds to variable tire sizes)

Now make an excel spreadsheet with 4 fields plus a calculated one.

Field 1: Chainwheel Tooth Count
Field 2: Rear Cog Tooth Count
Field 3: Speed (in MPH)
Field 4: Magic Number Constant (use list below)
Field 5: Calculated as follows

(1,056 * RearCog * Speed) / (ChainWheel * MagicNumber * 3.14159)

That is your cadence!

For example:
Chainwheel: 48
Cog: 16
Speed from computer: 20 MPH
Magic Number: 26.28 (700c wheels with 23c tires)
Cadence = 85RPM

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