Bicycle Network: Skill Up
A learner's guide to using gears
Why all those gears? What gear should I be in, anyway?
Today's entry-level bikes positively bristle with gears. If you find yourself feeling a bit bewildered, you're not the only one. City bike commuter Anna Fern gives you the low-down on using your gears.
What do gears do?
Gears help you to ride further and faster with less effort. Low gears enable you to spin the pedals easily. They are useful when you're pedalling uphill or for taking off from traffic lights. The very lowest gears, affectionately known as 'granny gears', help you get up steeper hills.
Higher gears feel harder to push against when you pedal. Once you start to get up some speed, you'll need to change to a higher gear. That way you can increase the resistance that you are pedalling against, so you can go even faster.
Pedalling speeds and gears
Many beginner cyclists pedal quite slowly when they start, putting more effort into each pedal stroke. In fact, it takes a lot less effort if you pedal faster at a constant rate, whether you're riding on the flat or up a hill. Your gears are the key to doing this.
You need to be in a low enough gear so you can spin the pedals quickly. The ideal number of pedal strokes per minute, called 'cadence', is around 60 to 90 strokes per minute. In other words, you should aim to turn each pedal at least once per second.
Try to keep your cadence constant across all conditions. For example, if you start going uphill, you need to change down to a lower gear so that you can still spin the pedals comfortably and maintain your cadence.
If you're used to pedalling slowly and pushing hard, pedalling at 60 strokes a minute may seem impossible at first. Just try to build up your speed gradually, and see what a difference it makes to your endurance.
What happens when you change gear?
Moving the gear lever on the left handlebar changes the position of the chain on the chainwheel (the spiky rings near the pedals). Moving the gear lever on the right handlebar changes the position of the chain on the back cogs (the spiky cogs on the back wheel).
Let's zoom in a bit more. The gear levers on your handlebars are attached to two cables. One cable goes to the back cogs, the other goes to the front chainwheel. Each cable moves a mechanism called a derailleur, whose job it is to move the chain into a new position.
It is helpful to watch your gears in action to understand what happens when you're riding. Stand next to your bike. Ask a friend to lift the back wheel off the ground. Turn the pedal with one hand and move the gear lever with the other. Watch how the chain moves into new position on the cog. Observe how the pedals need to be moving in order for this to happen.
The left gear lever usually controls the front chainring. Most hybrid and mountain bikes have three cogs on the front chainring, while road bikes usually only have two cogs. On the back wheel, there may be anything from 1 to 9 cogs. The right gear lever usually controls the back cogs.
Each combination of front and rear cogs creates a different gear. Most new bikes have numbered or 'indexed' gears. Cheaper bikes, however, might just have 'high' and 'low' on the levers.
Learning to use your gears
When you start out, leave the left (front) gear lever at 2, so the chain is on the middle chainring. (If you have only two front gears, have the chain on the easiest gear (the smallest chainring). Then practise changing the back gears, one gear at a time, using the right gear lever. You can make small adjustments to your pedalling speed using the back gears.
Remember, you need to be pedalling to change gears, so that the chain can shift onto the new cog and wind into place completely. Sometimes it takes a couple of pedals for the chain to move into place. Don't pedal too hard, though, as this will make the chain too taut to shift easily onto the next cog. If you're having trouble changing gear, try easing the gear lever a bit past the next gear to move the chain onto the ring properly.
Once you are comfortable using the back gears, experiment with changing the front gears (with the left lever) as well. Notice how the front gears give you bigger jumps in speed.
What gear should I be in?
Like driving a car, you generally start off in a low gear and change to higher gears as you build up speed. Most of the time you will use the middle gears.
If you're cruising on the flat, travelling downhill on a gentle slope or if you have a tailwind, keep your front gears high and then move your rear gears as high or as low as is comfortable. If you've been travelling in a high gear, remember to change down to a lower gear before you come to a stop - that way, you can avoid a painfully slow takeoff and save your knees!
If you're going uphill, change down before you have to push hard, so you can keep up your cadence. Try shifting the front gears down first, and then moving your back gears down as you need.
The following list is a guide to the best combinations of front and back gears:
- front 1, back lower gears (e.g. 1-3)
- front 2, back middle gears (e.g. 3-6)
- front 3, back higher gears (e.g. 4-7)
Avoid the following combinations, because they will stretch your chain too much:
- front 1, back top gear (7 or 8)
- front 3, back lower gears (1-3).
Practice makes perfect
Changing gears is not like flicking the switch of an appliance. You need to be aware of what the chain is doing as it moves to a new position by listening and feeling what your bike is doing. The more experience you get riding at different speeds on different inclines, the easier it will become.
How do gears work? (Getting more technical)
Most new bikes these days have around 15 to 27 gears. That means 15 to 27 possible combinations of front and back cogs. A car only has 4 or 5 gears, so why do bikes need so many speeds? The fact is that human legs are a lot less powerful than car engines, and they are a lot more sensitive to changes in terrain and speed. So we need more speeds. However, in real terms, there is some overlap between all those different combinations.
"When I was a lot younger I couldn't tell the difference between the gears and which combinations would be better. I didn't understand that smaller changes slowly going up would be more helpful than one big change. When I did physics in Year 11 we made these little bicycle car things. That helped me to understand how gears worked." Michaela, 17
Luckily, you don't have to go back to school and study physics to understand how it all works.
When you pedal, you push the front chainwheel around. This action moves the chain, which pulls the back wheel around. If the front cog is exactly the same size as the back cog, you get one turn of the back wheel for every turn of the pedals.
When you change the front gear up, the front cog will be bigger than the back cog. That means that one turn of the front cog will spin the back cog around more than once. So as you shift up a gear, you get more spins of the back wheel for each turn of the pedal.
When you change the front gear down to the lowest cog, the front cog will be smaller than the back cog. So one turn of the front cog will only spin the back cog part of the way around. In that way, lower gears help you to use many pedals to turn the back wheel around. So you're pedalling fast in order to slowly winch your way up a hill.
If you think about the previous information, you will understand this, even if it seems counter-intuitive:
- On the front chainwheel, the bigger cogs are the higher gears.
- On the back gears, the bigger cogs are the lower gears, and the smaller cogs are the higher gears.
So, bearing in mind that it's the relative size of the front cogs to the rear cogs that matters, a 27 speed bike does not really have 27 speeds. That's because several of those possible combinations of front and back cogs will probably result in the same number of back wheel revolutions per pedal.
This is the reason why the lycra brigade is very fussy about what gears they use on their bikes, and why they have their own favourite combinations of cog sizes.
You can work out what's going on with your own gear combinations (how far each gear combination will get you for each pedal) at this handy website.