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  Pedalling Cadence : Bicycle Gears Explained www.babs.co

A typical pedalling cadence for a competent older rider is around 75 r/min (the green column below). We'll excuse ourselves for dropping to 50 r/min whilst going up really steep hills; and some of us (guilty as charged!) feel the need for speed on descents which will 'necessitate' a burst at 100 r/min or a bit faster.

In our table the columns indicate our bicycle's speed when pedalled at 50, 75 and 100 revolutions per minute. Unless you're having fun in the mountains, there is simply no need to stray from the green column – keep your pedalling speed constant (75 r/min) no matter what your road speed might be.

Let's spell it out:

  • at 9 km/h our pedalling cadence should be 75 r/min
  • at 18km/h our pedalling cadence should be 75 r/min
  • at 36km/h our pedalling cadence should be 75 r/min.

Connection between Gears, Cadence & Speed

18km/h appears in each column. If this is our typical speed, we should maintain it by 'spinning' the pedals at 75 r/min, not straining along at 50 r/min or whizzing them around at 100 r/min.

  Metres Development km/h @ pedal cadence of…
    50 r/min 75 r/min 100 r/min  
  Your pedalling cadence is: Too slow! Just right! Too fast!  
           
granny gear 2 metres 6 9 12  
very low 3 metres 9 13.5 18  
low 4 metres 12 18 24  
mid 5 metres 15 22.5 30  
mid 6 metres 18 27 36  
high 7 metres 21 31.5 42  
very high 8 metres 24 36 48  
top gear 9 metres 27 40.5 54  

The range of gears shown in the table approximate those found on a bicycle with a triple chainset (50—40—30) and nine-sprocket cassette (12—30).

Imagine:

We are on an 18km out-and-home trip along a canal.

Unfortunately, we are not able to maintain our regular half-hour-each-way schedule because the outward trip is straight into a strong wind and we can only manage half of our normal speed (just 9km/h). We turn around and zoom home at twice our regular speed (36km/h!).

Now look at the green column which shows "just right" pedalling cadence. -->We still turn the pedals around at our customary 75 revolutions per minute on both the slow outward and the speedy return trip.

Comment:

Perhaps, this is the time to suggest that you equip your bike with a computer that displays cadence (pedalling speed). Watch the cadence readout and keep it high by changing down a gear or two.

Your cycle computer should be set to display both current cadence and average cadence. Avoid pedalling too slowly (aim for 80 r/min but be satisfied with an average of 75).

We really should avoid the extreme speeds shown in the table: 6km/h is approaching 'wobbly slow' and 54km/h is nearing 'terminal velocity'. That means: 75 r/min is appropriate for almost all of our cycling. Keep to that cadence by changing to a suitable gear!


  Bicycle Gears Explained www.babs.co
  -->Metres Development – metres travelled per pedal revolution.
-->Pedalling Cadence – pedalling r/min x gear selected = speed.
-->Tyre Circumference – an easy way to measure it.
-->Derailleur Gears – simple formula for calculating metres development.
-->Hub Gears – not-so-simple formula for calculating metres development.
-->Gain Ratio – distance bike travels : distance pedals moves.
-->Gear Inches – archaic system for penny-farthing high wheelers.
  BABS.CO » Bicycle Gears » Pedalling Candence  
2013-06-16 18:01
 

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