Gears. Amazing things. The combination of two different sized cogs and a chain lets you power down hills, cruise on the flat and climb up a gradient. What a great invention. Not that I'm knocking single speeds - which we all ride here in the workshop - but the multi-geared bicycle is a formidable invention.

Changing gears, though, is another matter. Most modern bikes are equipped with a derailleur gearing system - stay with me, we’ll get to the terminology - where the chain runs between many different cogs. These cogs are both turning between your feet and attached to the rear wheel, giving the rider a sometimes bewildering number of gears to choose between, the most common being 21, 24 or 27.

Trying to avoid a massively technical breakdown of the physics of how bicycle gearing works, this article focuses more on the practicalities of changing and operating gears.

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Riding a bike with gears can be quite a daunting experience. With practice and understanding, though, the relationship between you and your steed can become a truly satisfying experience. When you press that shifter/lever, twist your wrist or change gear with your newly invented, helmet mounted, laser guided unit, it really helps to have some understanding of what is actually happening back there.

If you would like it to be really easy, think about getting a bike with an internal rear hub. With these, the chain runs on just one cog and all the gear changing action takes place in the hub - very clever. Back in the day these generally had just three gears and were found mainly on traditional and ladies bikes. Today there are some excellent modern internal hubs with 7, 8 and even 14 gears. We regularly convert our customers’ bikes to use these.

If your chain moves between different cogs on the rear wheel, then you have a derailleur gear system. At least 95% of the bikes we see in the workshop are fitted with these. They are more complex to use than an internal hub, but have a lot of advantages.

Please note: Throughout this document it is assumed that your bike is in good working order and that your gear systems are correctly set-up and in tune.

Try not to be daunted by your gears. A little understanding can go a long way.

Your derailleur gear system consists of:

Shifter – The device you use to change gear, that is to make the chain move between cogs. This may be a lever, twist grip or other. Most bikes will have two shifters.

Chainrings – These are the one, two or three cogs that are between your feet and on which the chain runs. Combined they are known as a ‘chainset.’ The left hand shifter moves the chain between these cogs using a…

Derailleur – These are the very clever devices that move the chain between the cogs. So called because they 'derail' the chain - not as I thought for many years named after a French man called 'Monsieur Derailleur.' Bikes have both front and rear derailleurs. Whereas your front derailleur moves the chain between your chainrings, the rear derailleur moves it between your…

Cassette/Block/(Multi)Freewheel – These are the rear cogs attached to your back wheel. There can be anywhere between 5 and 10 of these. (In fact on the day I type this I have learned that an 11 Speed version is being released – madness. I mean, really?)

Sprocket – One of the cogs making up the above.

Chain – Well, I'm sure you know what this is.

Cranks – These are the two arms into which the pedals fit. The RHS (Right Hand Side) crank is attached to your chainset.

Transmission – This is a collective term for your chain and the cogs on which it runs (the Chainset and Cassette). The transmission ‘transmits’ your pedalling action into movement of the rear wheel and then off you go.

Components – Pretty much anything that attaches to your frame that is essential for the operation of your bike. (Anything attached that is not essential, we would generally refer to as an accessory rather than a component.)

LHS or RHS – ‘Left Hand Side’ or ‘Right Hand Side’

Low/High - A common problem when discussing people’s gears and their operation is varying terminology for which gear they are in. “It doesn’t work in 3 and 4,” for example can be quite ambiguous. It is more useful to talk about low and high gears. Low gears make pedalling easier and are used for setting off and going up hills. High gears are used when you have built up speed and are travelling faster. On your rear, wheel the low gears are the bigger cogs and the high gears are the smaller cogs. Conversely at the chainset, the smaller cog (often known as the granny ring – can you guess why?) is your low gear, whilst the big cog is your high gear. Complicated, isn’t it?

Your point of contact with your gear systems is a ‘shifter’ of some type.

In the olden days, to change gear with a derailleur, you had to judge how far to pull a lever to make the chain move between the cogs, known as ‘friction shift.’ These days most shifters are ‘indexed,’ so you ‘click’ to change gear. Indexed shifting is a superb invention, but it does not make changing gear foolproof, far from it.

Firstly - and this really is one of the most important pieces of advice that I can offer - if your shifters have a visual display of what gear you are in, a number or the like, try not to look at it! Riding a bicycle with derailleur gears means that you are operating a mechanical linear machine. It is not like using a TV remote control, cash point, computer or the like.

When you move your shifter, you are pulling an inner cable that is sliding under resistance through an outer cable and forcing a derailleur to change shape, thus pushing a chain sideways and hoping that it will move on to another sprocket. You are in charge of this action. It is a complicated system and requires skill, timing, anticipation and concentration.

Once you have become confident operating them, you will instinctively know which gear you are in. Try to understand when and how to operate your shifters and thus ‘feel’ your gears change, rather than just push a button, look at a dial move next to it and hope that something happens

Ok, as outlined above, you probably have two sets of gears on your derailleur-equipped bicycle.

The Rear Derailleur / RHS Shifter

The right hand shifter is on the right of your handlebars (as you look forward whilst on the bike) and controls the rear derailleur, which moves the chain between the sprockets on your rear wheel. This is the shifter you will use the most and can very roughly be approximated to the gears on a car. The lower gears (in use when the chain is on the bigger sprockets) are easier to pedal in and are used for setting off from stationary and riding up hills. Then work through the gears (from the low to the high) as you build up speed and travel along the flat or go down hills. Changing gears with the RHS shifter should be very clean and over time become second nature - just a click and then a smooth transfer of the chain from one cog to the next. Constantly assessing what lies ahead and how to respond to it, you find yourself changing gear automatically to deal with any eventuality. This may sound a bit wistful/idealistic, but it really can be like this.

The Front Derailleur / LHS Shifter.

This is the big one and if the truth be told the reason behind my writing this article. If you have two or more chainrings (the most common is three) then you will have a LHS shifter that moves the chain between these chainrings using your front derailleur. Smaller chainrings are easier to pedal in, but less power is transferred to the rear wheel. Conversely the largest chainring provides more power to the rear wheel, but is harder to pedal in. Which to use and when depends on many different factors. If you only ride on the road and don’t tackle any extreme hills you may never need to use the smallest chainring. I would suggest using the middle chainring for setting off, casual riding and most hills; the largest one for riding fast, pushing the bike hard on the flat and down hill.

Issues with shifting the chain between the chainrings using the LHS shifter are probably the most common problem we see. All is not lost, though; it is not some kind of weird and wonderful black art. However, it is the most difficult part of operating the gears on a derailleur system. The jump in the number of teeth between the different sized chainrings is far greater than between the sprockets on the rear wheel. The front derailleur is a very different device to the rear and the advice to ignore the numbers on the shifter holds even truer for this. Whereas the rear derailleur holds and guides the chain very specifically, the front derailleur essentially just uses two plates either side of the chain to push it sideways. The rest of the work is done by the rotation of the chain and chainset (through your nice smooth pedalling action) and the ‘hook’ effect of the cogs on the chainring that is being changed. The idea is that the hook picks up the chain and engages it on the new cog.

Generally changing down (from bigger to smaller chainrings, so the chain is moving from right to left) is easier as once the shift is made, the derailleur pushes the chain sideways and it drops down through the space onto the smaller chainring, where the teeth will pick it up. Harder is the shift upwards to a higher gear (from smaller to bigger chainrings, so the chain is moving from left to right). When you operate your LHS shifter to move into a higher gear, often two extra things are needed over and above a normal shift. These are the ‘extra push’ and the ‘pregnant pause’.

‘Extra Push’ – It is a hard trick for your chain to move up to a bigger chainring and it often needs a bit of extra encouragement. If you just gently click your left hand shifter into a higher gear often it will cause the front derailleur to push the chain sideways, but it will not engage with the bigger chainring and instead will just rattle around in a kind of state of limbo - trying to move to the bigger chainring but still actually on the original one. The impetus of the shift has gone as the ‘click’ has been made, but without a corresponding shift. This is why the ‘extra push’ is needed. When you operate your left hand shifter to change to a bigger chainring, depending on its type, give it a bit of extra ‘push’ or ‘twist’. This will push the chain slightly further and give added encouragement for it to be picked up by the teeth on the larger chainring. Don’t release the lever straight away but wait – this is the…

‘Pregnant Pause’ – When changing to a higher gear (bigger chainring) using the left hand shifter, don’t just ‘click’ and then let go. Use the ‘Extra Push’ and then wait for a short moment – this ‘Pregnant Pause’ this will give the chain a moment to engage with the teeth on the larger chainring and then settle onto it. Once you have felt/seen this happen, and then let go of the shifter. With the chain happily moved onto the bigger chainring, the front derailleur will now settle in its normal position.

This may all sound very complicated but once mastered you’ll hardly feel that you’re doing these two things. They really can be very subtle but have a big impact on your gear changing experience.

If your bike is correctly set up, then when you are in the middle chainring (if you have three) and the middle sprocket of the rear wheel, the chain will run in a perfect straight line, parallel with the wheels and direction of the bike. As you use different combinations of gears, the chain will flex from side to side to accommodate the difference between the lateral positions of the front and rear cogs on which it is travelling. This angled line that the chain follows is known as the chain line.

Many riders are unaware that certain combinations of gears should not be used. In the most extreme combinations of gears - either running the chain on the largest chainring and the largest sprockets on the rear wheel, or the smallest chainring and smallest sprockets - the chain line will become very severe. This results in extremely poor operation, rapidly increased component wear and potentially the chain coming off and jamming, even on an otherwise correctly set-up and maintained bike. By not attempting to select these gear combinations, you will enjoy improved performance, greater reliability and increased component and, in particular, transmission life.

The following three images illustrate normal variations in chainline, demonstrated on a bike with a single front chainring. Click on the images for larger versions and further detail.

       
The next three images show the effect on the chainline of selecting the most extreme combination of gears. As before, you can click on the images for larger versions and further detail.

       

Pedalling – Change gear when you’re not straining the chain with effort, but when your legs are just smoothly rotating. Modern cogs have little ramps and ridges built into them to aid the smooth transfer of the chain from one to the next. A naturally flowing chain will follow these, giving that satisfyingly smooth shifting feeling.

Change through the gears one or two at a time - It isn’t a simple as just ‘clicking’ your shifter. Making the chain ride up and engage with another cog is a combination of your smooth pedalling action and a crisp clean shift. Sometimes you need to press your lever or twist your wrist just that little bit more before you release it. Aim for a good firm shift rather than a cautious hesitant one. Every shifter/derailleur combination is different; develop a feel for yours.

Anticipation is key – With derailleur gears, you cannot change gear when you are stationery and changing out of the wrong gear whilst you are going slowly or pedalling up a hill for example can be very difficult. You need to be in the right gear for the moment. Always remember to change down to a low gear before coming to a stop or hitting a hill. This will keep you ahead of the game and help you to avoid the dreaded ‘crunch’. For example, try to link seeing a red light up ahead with changing down. You'll soon find yourself doing it automatically.

Crunch – You know that nasty noise that comes from your gears when you try to change gear when the chain is under excess strain? It hurts your bike. If I said excruciatingly, I’m sure you’d think I was exaggerating, but when you hear it, it means your bike is in pain. I’m not talking about odd clicks and ticks that are a normal part of riding nearly all bikes; I’m talking about the crunch. I reckon I crunch my gears about once a month. (Maybe on a bad month three times.) If you can eradicate the ‘crunch’ from your time in the saddle, then your relationship with your gears will become a beautiful thing.

Avoid trying to change gear when you are ‘out of the saddle’ (i.e. not sitting on your saddle) when your weight is being borne by the pedals. The pedals are being held back by the resistance of the gear system and rear wheel, as transferred by the chain. Your chain is under full stain and not in a position to smoothly change gear.

Use a good selection of your gears and spread the wear. Try to avoid the temptation just to cane it around in top gear. If you spend most of your time in just one gear it will soon wear out. By varying the gears you use, your transmission will last much longer.

Backpedalling – When in gear, backpedalling is usually fine, but whilst changing or if your gears are not properly in tune, it can quickly throw the chain off - with potentially serious consequences. I’d keep it to a minimum.

Now this may all sound like just too much effort. But really it is not, what is needed is quite simple: PRACTICE.

Just like operating virtually any other mechanical device, riding a bicycle equipped with derailleur gears is a skill. The more you do it and the more concentration and focus you put into learning to do it, the better you will get and the more natural it will become. In addition, every bicycle has its own particular foibles. You need to get to know your bicycle and how it works and responds to you.

We regularly see customers who have gone out and bought a new bike (often a cheap and poorly set-up one) and with little or no experience as how to operate it, set off to use it. They quickly become frustrated and dissatisfied with their riding experience. But little wonder – should someone drive off in a car with no real knowledge of how to operate it? Or perhaps attempt to operate a machine in a factory with no training? It’s true that many people do have experience of riding a bike from their childhood, but this is rarely enough to be able to successfully set off into the traffic on a modern adult bike.

What is needed is practice. Pick a quiet day and go to an empty car park or similar flat, paved, open space. Ride around and practise changing gear. Work your way through them, stop and start, develop a feel for how your bike and its gears operate. Start to build that relationship – where you are in control. Once you feel comfortable on the flat, progress to some more challenging roads.

Even better, go for some lessons. There is an excellent charity based here in Hove called Bike for Life that does adult cycling lessons both one-on-one and in groups. These can be invaluable in helping you develop a good relationship with your bike and your road use as a whole.

Something we often hear goes along the lines of, “oh, I don't use my gears, I don't really need/understand them.”

Fair enough, not everyone needs the latest 27 Speed high specification machine. But gears are there for everyone. Although they can be quite daunting at first, with focus and practice, this will soon pass. By using them you’ll find that your cycling experience will be much improved and your bike will thank you for it. Smooth, regular use of your gears will result in a better-working, longer-lasting and more reliable ride.

The relationship between you and your bike should be of master and servant. You are in control; it does what you tell it. Learn how it works, treat it well and it will give you much benefit and pleasure.