How Gears Work
Today most bikes come with multi-speed gears that assist the rider to climb hills comfortably or to
go faster downhill. Knowing how your gears work and using them plays a big part in your overall
enjoyment of biking.
When you are pedalling at your ideal speed you are putting out the greatest amount of power that
you are able to sustain efficiently. You select your ideal speed by shifting the gears and this
will depend on the slope of the road, the wind conditions, and your own physical condition at any
given time.
Your bike has 3 chainwheels in the front and either 7, 8, 9 or 10 sprockets at the rear along with
front and rear gear shifting mechanisms known as derailleurs. Each chainwheel and sprocket has
teeth and these can vary in numbers from, in the front set, the big ring 48 to 42 teeth, the middle
ring 36 to 32 and the small with 26 to 20 teeth. On the rear cluster of sprockets you will have a
range of 32 to 11 teeth. Depending on what combination of front chainwheel and rear sprocket you
choose results in a situation where, for one revolution of your legs, you will achieve a different
number of revolutions for the rear wheel.
The best way to explain this is with some simple maths. With your gears set on the largest 42 tooth
chainwheel at the front and the smallest 11 tooth sprocket at the rear apply this equation: 42 ÷ 11
= 3.8. This tells you that for every one full turn of the front chainwheel your rear wheel would
have gone around 3.8 times and is the ideal gear choice for going down hills or with a strong wind
behind you. Alternatively with your gears set on the smallest 22 tooth chainwheel at the front and
the largest 32 tooth sprocket at the rear apply this equation: 22 ÷ 32 = 0.68. This tells you that
for every one full turn of the front chainwheel your rear wheel would have gone around .68 times,
just over half a revolution, making this the ideal gear choice for steep grades.
Take the time to learn how the gears work on your bike following some simple guidelines as outlined
below.
Always pedal forward - the chain can only move sideways while it is also moving forward so you can
only shift while you are pedalling forward.
The rear derailleur shifts using the bottom of the chain loop, which is under light tension from
the derailleurs pulleys and springs. The front derailleur shifts using the upper part of the chain,
the part that transmits power to the rear wheel. As a result, the front shifting will not work so
well while you are applying full pressure to the pedals. The rear derailleur can usually shift
under full load, but we advise you ease up a bit during the shift as this will help increase the
life of the chain.
Don't criss-cross your gears, gear choices that have the chain working on an extreme angle, as this
is bad for the chain and the sprockets. Try to visualize gear shifting in terms of where the chain
is, rather than by the positions of the shift controls on you handle bars.
Maintenance Schedule
At Avanti Plus Nelson we recommend following our
regular bike maintenance
schedule
and remember we carry out most major repairs as well as regular maintenance.