Unless you ride a singlespeed bike, the gears on your cassette and chainrings are there to make your life easier, not to be confusing or cause any sort of complication. However, it isn’t uncommon for new cyclists to find them either troublesome, or just to ride in one gear to avoid having to shift.
I’ve seen plenty of people rolling along with their legs spinning like pinwheels, because they need to select a higher gear, or grinding up a hill because they need a lower one. Nobody is perfect, and I’m known to grind in some situations, but being aware of the do’s-and-do-not’s will certainly help you get it right.
Most bikes will have two or three front gears, controlled by the left hand shifter, and then up to 11 rear gear options, controlled by the right hand shifter.
The front gears, which are on the chainset next to the bottom bracket, make big differences. A steep hill will be easier in the smallest ring, whilst flat or downhill roads can be tackled in the biggest ring.
The rear gears are about fine tuning. The closer the ratio on your cassette, eg the smaller the difference between the smallest and largest ring, the less noticeable and smoother the gear changes will be. For example, an 11-23 cassette has 11 teeth on the smallest cog, and 23 on the largest. An 11-28 has 11 and 28 teeth. The 11-23 will give you fewer options – you won’t have a 28 tooth cog to drop into on a big hill. However, you’ll get closer to the ‘perfect’ gear because shifts between the cogs will make tiny changes.
If you plan to be riding up hills, and want to make your life easier, a wider ratio cassette is the best option for you. Close ratio cassettes are favoured by performance cyclists, to whom every second counts.
One thing you don’t want to do is ride in an ‘easy’ chainring (the smallest ring), and a ‘hard’ rear gear (eg the smallest cog), or a ‘hard’ chainring and ‘easy’ rear gear. This is called crossing the chain – if you look down when in this position, you will see it is being pulled as tight as possible. This causes the chain to stretch, as well as wasting some of the power you transfer through the pedals.
It’s easy to end up doing this when you’ve begun a hill in the large ring, and gradually gone down the gears of the cassette – but you can avoid doing this with forward planning. Ideally you should avoid changing front gears on a hill, when you are placing pressure on the chain, you can anticipate what is coming, and shift down early. Start a hill in the small chainring, with your chain in the middle to high end of the rear cassette, and you can drop down gears as you need to without worry.
It is also best to try to move through the cassette gradually – aim to click up or down one gear at a time, soft pedaling as you make the shift to decrease the liklihoood of your chain coming off, and keeping your legs moving between each change.
The perfect gear
You’ll know you are in the perfect gear, because your cadence will be spot on. Cadence is the term used to describe the number of pedal revolutions per minute (RPM), and the recommended average is 90 – though this absolutely does vary between individuals.
You can track cadence either with a cycling computer, or by counting the number of times a minute your pedal reaches the bottom of the stroke. The latter of course requires a lot of concentration, and it’s unlikely you will be able to keep it up over a long ride.
If your RPM is well below 90, and you feel like you are wading through concrete on your ride, you need a lighter, easier to pedal gear. If it is well above 90, and you feel you aren’t going very far for the amount of effort being put in, select a higher, harder to pedal gear.
Situations which require a lower gear
1) Up a hill. Try to be in the appropriate chainring at the bottom of the hill, so you don’t need to change the front gears on a climb, use the rear gears to make your life easier, clicking down to lighter gears as the incline builds. If you are using a cycling computer which tracks cadence, try to keep it above 80 RPM, but do remember this is a guide only – your body will probably tell you what is right for you – just avoid feeling like you are leg-pressing your way up the climb.
2) When riding in a headwind. Annoying as it is, when riding into a headwind, mother nature has added to the amount of resistance you come up against when pedaling. A high gear means more resistance, too – so the best way to counter what the weather has thrown at you is to lower the resistance at the pedals, selecting a smaller chainring, or bigger (easier to pedal) cog on the cassette.
3) When you stop at traffic lights. The gear that felt comfortable when you were rolling along won’t feel so easy when you move off from a total standstill. As you come to a halt, slowly click down – making sure you have pedaled a few revolutions before actually stopping – to ensure that the chain is biting the cassette.
4) Before a corner. Cornering is best when you slow down to the appropriate speed, and shift down a couple of gears before reaching the bend. When you come out of the bend, you’ll want to accelerate get yourself up to speed again, and this will be easier if your gears are readily adjusted to the slower speed. Accelerating in a high gear, when your speed has been reduced, is much harder.
Situations which require a higher gear
Higher gears are for the fun times – the going downhill fast times, the long flat sections of road. Remember to keep your cadence at a rate that is comfortable, if you get the ‘wading through treacle’ feeling, you probably need to change down, as placing too much load on your joints can result in injury. However, if you find your legs moving comfortably around a big gear, it’s time to let loose and enjoy the feeling of going fast.