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Sure, everyone knows what “21 speed gears” means on a bike… right?
Well, maybe not. Bicycles, and especially gear systems, can be quite perplexing.
With 21 speeds, how do you know when (and how!) to change gears on your bike?
When you’re going uphill, which gear should you use? How about when you’re going downhill or just riding along on flat pavement?
And, where are the gear shifters on a bike?
On a mountain bike or a hybrid bike, the shifters are easy to identify (they’re simply near the brake levers if you’re wondering!)
For road bikes though, it’s a little different: the gears are not controlled by separate shifters; they are actually built into the brake levers.
Even the phrase “21 speed” is a little deceptive. To be more accurate, for each “speed,” you could pedal along at the SAME miles/hour on your bike.
Isn’t it strange? Yep, well what it really means is that you have a choice of 21 different gears when cycling. You can pick any one of these gears at any time, and it will either make pedaling on the flat or up/down a slope easier or more difficult at that moment.
So, yes, bicycle gear systems are difficult to understand.
The aim of this article is to explain what 21-speed bike gears are. In plain language that, I hope, makes sense.
I’ll tell you how to shift gears on the most common styles of bicycles.
Then, I’ll explain some of the bike gears terminology that you need to know (e.g., “low gear” and “high gear”).
We’ll examine what gear you should use when ascending hills and what gear you should change to descend.
In addition, we’ll discuss certain gear combinations to stay away from while riding (commonly called “cross chaining”).
Let’s switch things up a notch and get into the nitty gritty.
What does 21 speed mean on a bike?
If you’re looking at a 21-speed bike, it’s important to realize that you won’t see 21 different gears.
Instead, you get three cogs (which are called “chain rings”) near the pedals at the front of the drivetrain*. At the rear wheel hub, there are seven additional cogs (which together are known as a “cassette”).
*All the components on a bike that make the wheels move are collectively called the “drivetrain”. These include the two pedals, all the cogs on the chain rings and cassette, the chain and front/rear derailleurs.
The image below demonstrates what this looks like from a side view.
The total number of gear combinations that you may get from all these cogs is equal to 21, when you multiply 3 cogs on the chain rings by 7 cogs on the rear cassette.
When you sit on the bike and look down at the drivetrain from above (see diagram below), you can see how all of these pieces work with each other more clearly: by moving the chain across to connect any two cogs, different gear combinations are chosen.
So, on a 21-speed bike, how do you shift gears?
How do you change gears on a 21-speed bike?
Bear in mind, that you don’t ever have to change gears when you’re cycling if you don’t want to – the chain will connect a chain ring (one of the front cogs) and a cog from the rear cassette – and you can stay in that gear.
However, you’ll discover that it’s sometimes difficult to pedal (for example, when you’re going up hills), while at other times it will be too easy (going down steep hills, say), resulting in your legs spinning out excessively.
So, it’s time to make a (gear) change!
On the handlebars, there are two gear shifters that can be operated by hand. These are linked via cables to the front and rear derailleurs:
- Left gear shifter controls the front derailleur.
- Right gear shifter controls the rear derailleur.
In French, the word “derailleur” (more properly, “dérailleur”) means to de-rail. In bike terms, it’s the chain that is being derailed, as the derailleur knocks it off one cog and onto another.
At the crank, just on top of the chain rings, you’ll find the front derailleur.
At the rear wheel hub, where the rear cassette lives, you’ll find the rear derailleur (which sits just below the cassette).
Bikes manufactured in the last 20 years or so are likely to have one of just a couple variations of gear shifter:
On road bikes, the gear shifters are incorporated into the brake levers. Often these will operate be pushing the brake lever to one side to shift one way and pushing a separate button or lever to shift the other way.
It’s a little easier with electric bikes, fitness bikes, city bikes, hybrids and MTBs as the gear shifters are normally separate to the brake levers (although generally they’ll be positioned next to the brakes). Each gear shifter will comprise two levers – push one to change up a gear and the other to change down.
With either style of gear shifter, the left will control the front derailleur and the right controls the rear derailleur.
It’s important to remember that you need to keep pedalling whilst you’re shifting gears – the chain can only move from one cog to another when it’s going round the drivetrain.
Which gear on a 21-speed bike is best for going up hills?
To make pedalling uphill easier you need to shift into a ‘low gear’.
But, what exactly IS a ‘low gear’?
The graphic below should hopefully explain.
If you use the left gear shifter to move the chain across to the smallest of the front chain rings then you will be in one of the lowest seven gears that you have on the bike.
This will mean that you won’t have to push the pedals so hard as you climb hills, though you’ll find that your legs will be turning the pedals faster.
For the steepest climbs, you should shift to your lowest gear (“gear 1”). To find this, use the left gear shifter to move the chain to the smallest of the front chain rings. Then, use the right gear shifter to move the chain to the largest of the cogs in the rear cassette.
PRO TIP: always change gears one at a time. If you try and leap through lots of gears in one go, you will likely find that the chain can either get stuck, come off the cogs, or both.
Which gear on a 21-speed bike should you use for flat or going downhill?
At the top of a slope, you need to change gears from a low gear to a higher gear. This will stop your legs from spinning too fast and mean that you cover more ground with each turn of the pedals.
High gears on a 21-speed bike look like the graphic below:
To move into the high gears, use the left gear shifter to move the chain to the largest of the three chain rings at the front. You’ll now be in one of the highest seven gears on your bike.
When you’re going down steep hills or cruising along at a steady speed on the flat, you should move into your highest gear of all (‘gear 21’ or your ‘top gear’).
To get into the highest gear, make sure you’re on the largest chain ring at the front and then use the right gear shifter to move the chain to the smallest cog at the rear wheel.
PRO TIP: Always look at the road or trail ahead so you can plan what gear you’ll need coming up.
If you’re in low gear and about to descend a steep slope, your legs will just spin (change to a higher gear!)
If you’re in high gear and about to go up a steep hill, your legs may not be able to turn the pedals (change to a lower gear!)
The dangers of cross-chaining
Sadly there are a couple of gears in the twenty-one that you shouldn’t use.
These are:
- Biggest cog at the front and biggest cog at the back
- Smallest cog at the front and smallest cog at the back
You can see them in this graphic:
Why is this? Well, you’ll see that each of these pulls the chain diagonally across the drivetrain.
This can cause undue wear to the chain and may also be quite noisy as the chain slips and clunks its way around.
And there’s really no need to use either of these gears because you have nineteen others to choose from that will all make your chain happier!
Conclusion
Bike gears can be confusing and, when you have twenty-one of them, even more so!
Keep the following rules in mind and you’ll soon have the hang of them though:
- Left shifter for front derailleur / Right shifter for rear derailleur
- For uphills, make sure the chain is on the smallest front chain ring
- For downhills or cruising along the flat, make sure the chain is on the largest front chain ring
Related
FAQs
21 Speed Bike Gears Explained (Understanding Your Bicycle)? ›
A 21-
21-Speed Bike Gears Explained
Unlike a 7-speed bicycle, a 21-speed bike has 3 chainrings at the front of the drive chain. These three different chainrings allow for three times as many gear ratios to be created using the 7-speed cassette.
The rear cassette features seven gears, controlled by your right handlebar shifter. The smallest rear gear is the hardest and the largest is the easiest.
What do the numbers on bike gears mean? ›Most bikes built in the last few years have between 8 and 11 cogs in the cassette. The largest cogs are closest to the wheel and the gears are numbered from the inside out. The larger the cog the 'lower' the gear and the easier it will be to pedal, but the slower you will go.
Is 21 gear cycle good? ›21-speed bikes are designed for a few different purposes. First, they're great for riders who want a bit more versatility in their riding. 21-speed bikes can be ridden on a variety of terrain, whether it's paved roads or off-road trails. Second, 21-speed bikes are also great for riders who want to be able to go faster.
What order should gears be on a 21 speed bike? ›Gear Setup
A 21-speed bike has three front gears and seven in the rear. The front gears sit in line with the pedals and are called chainrings. The rear gears are in line with the axle of the rear wheel and are called the cassette collectively and cogs individually.
Low Gear = Easy = Good for Climbing: The “low” gear on your bike is the smallest chain ring in the front and the largest cog on your cassette (rear gears). In this position, the pedaling will be the easiest and you'll be able to pedal uphill with the smallest amount of resistance.
What speed should a bike go in 1st gear? ›- As a general rule, on a low capacity bike, 1st gear for up to 10mph, 2nd for up to 20mph.
What gear should I be at for each speed? ›| Gear | Speed |
|---|---|
| 1st gear | Between 0 mph and 10 mph |
| 2nd gear | Between 10 mph and 20 mph |
| 3rd gear | Between 20 mph and 30 mph |
| 4th gear | Between 30 mph and 40 mph |
A high gear, sometimes referred to by cyclists as a 'big gear', is optimal when descending or riding at high speeds. The highest, or biggest gear on a bicycle is achieved by combining the largest front chainring size with the smallest rear cog or sprocket — expressed as '53x11', for example.
What gear should I bike in on flat road? ›
The middle gear is ideal for regular or flat terrain when cycling. It provides a little bit of resistance without making it overwhelmingly hard to pedal. For a smooth ride on a flat road, you should combine the middle chain ring with one of the middle gears on the rear cassette.
Does the number of gears matter? ›Quite simply, the number of gears doesn't really matter. It all comes down to the ratios of gears. We highly recommend getting gearing which offers a lot of lower ability, as this is what you generally will be using much more.
What is the best gear ratio for cycling? ›For flat places, a ratio of 2.6 to 3.0 is ideal for most people. The lower value of this range, with a cadence of 90 rpm, will allow us to ride around 30km/h, while the upper, 34km/h. If you're just starting out on your adventure on a single speed or fixed gear bike, a gear ratio of around 2.7-2.8 will be ideal.
What speed bike is best for hills? ›If you live in an area where there are rolling hills, we highly recommend purchasing a 7 speed or a 21 speed. We don't recommend the 3 speed because it does not have a wide enough gear ratio to get you down to a real low gear to get you to the top of the hill.
What does 21 bike mean? ›A 21 inch bike frame is an XXL size suitable for people over 6 foot 2 inches tall.
What is the price of Shimano 21 speed gear cycle? ›15.50 K in India.
What gear do I use to go downhill? ›Downhill: Use first gear when driving downhill as a primary source for braking. Engine braking means you don't need to use the brake pedal as much, which keeps your wheels turning. If the wheels are turning you can steer, important when undertaking a steep downhill run.
Should you change gears while pedaling? ›Pedal slightly easier while shifting
While you are shifting gears, you must keep pedaling in order for the chain to move from one gear to the next. When you're in a particular gear and pedaling, the chain is pulling on the teeth of that gear.
This can be achieved by using a higher front and a smaller back. Essentially for going downhill, you want to use a chainring with more teeth and a cog with a very low number of teeth on your cassette.
What speed is 2nd gear on a bike? ›Second gear (15-30 km/h): when the bike riding begins. A 2nd gear is highly recommended for busy roads or inactive traveling.
Do you go faster in a higher gear on a bike? ›
Pedaling normally in a higher gear means you will go faster, but with a lower torque. This is good for going out on a flat road or even downhill.
How fast is 2nd gear on bike? ›Second Gear
Second is still considered a lower gear, between 15 to 30 km/h, and it's best suited for riding in heavy traffic, crowded roads, or bumpy terrain. The biggest difference between first and second gear is that the bike starts to feel more comfortable.
Within the engine at that point, an over-rev condition will occur and internal-engine components will momentarily spin far faster than what they were originally designed to do. The valve spring keeps the engine's valves seated, opening and closing following the camshaft lobe.
What happens if you go too slow in a high gear? ›Would it wear out the engine or transmission faster? Just cruising at the lower speed in the higher gear will not incur any extra wear to engine or transmission. In fact, you'll see less wear due to running the engine at a lower speed. That difference will not be much of a difference, but there will be a difference.
How do I choose gears? ›When selecting a gear the workload and environment of the gear set should be considered. Power, velocity and torque consistency and output peaks of the gear drive so the gear meets mechanical requirements. Inertia of the gear through acceleration and deceleration. Heavier gears can be harder to stop or reverse.
How fast is a 21 speed bike? ›A 21-speed bike can go as fast as 44 mph (70 km/h). But that requires a fit rider and a light bike with good gear ranges.
Why is my bike hard to pedal uphill? ›The most common reasons you might find it hard to pedal your bike are that you are in the wrong gear, your tire pressure is too low, or the bike wheels are rubbing against the brake pads or frame.
Which gear to use in normal road? ›Low Gears, Middle Gears, High Gears
There are three types of gear; low gear, middle gear, and high gear. For riding on flat roads, it is recommended to use the middle gear.
Average Speed on Flat Ground: 25-28 mph
The average speed for professional cyclists while traversing on flat terrain is 25-28 mph. The average amateur cyclist travels about 17-18 mph while on flat ground.
In general, you'll want to keep this rule of thumb in mind: the lower the gear, the more power you have available. The higher the gear, the faster your engine runs! With both manual and automatic transmissions, you'll generally move from lower to higher gears as you accelerate.
Which gear number is the fastest? ›
The gears determine the amount of power available from the engine. First gear provides the most pulling power but the least potential for speed, whilst fifth gear which provides the least pulling power allows the greatest range of speed.
Is more or less gears better? ›As a general rule, the more torque an engine has, the less gears the transmission needs to provide performance. Some of the most powerful drag cars have only two or three gears in their transmissions, but on the street, having additional gears will give you smoother performance and better fuel economy.
What gear ratio should I use for uphill bike? ›The most preferred gear ratios on such tracks are 50/34, 40/34, 36/40, 34/36, 34/32, 34/30, and 32/20. However, remember that using gears with such a low ratio will cause you to pedal more, but it will require less effort.
Is a 21 speed good for hills? ›The 21-speed bike is made for flat ground and steep hills. The 21-speed bike will allow you to conquer any hill you throw at your bike. It's got super low gear to take you up a real steep hill. You can also go really fast putting it in the highest gear.
What is the most comfortable bike for seniors? ›Recumbent Bikes
A recumbent bike allows you to cycle in a semi-reclined position, with the bike's pedals in front of you instead of underneath you. This bike style is a great choice for anyone who needs back or neck support or wants to reduce pressure on their knees.
The difference between the 27 and 24 speeds is that they have larger or smaller ratios than the 21 speeds, which allows you to run more and save more energy. The 24 speed bike can reach 1.07 ratio even when using 2*1 ratio, if the flywheel is 11~32 bike, it can reach 1 ratio, (the minimum ratio of 21 speed is 1).
What size bike should a 5 10 man ride? ›| Rider Height (feet/inches) | Rider Inseam (inches | Bike Frame Size (centimeters) |
|---|---|---|
| 5'8"-5'11" | 30.5"-32" | 56-58 cm |
| 5'10"-6'1" | 31.5"-33" | 58-60 cm |
| 6'0"-6'3" | 32.5"-34" | 60-62 cm |
| 6'2"-6'5" | 34.5"-36" | 62-64 cm |
Shimano is easily the most effective and busily innovative gear manufacturer. They have an incredible reputation for quality and efficiency right across their range, and are used on over 70% of bikes manufactured across the globe.
Why is cycling gear so expensive? ›Sponsorship and marketing is perhaps the biggest expense (outside of operating costs) of many brands, and supplying an average WorldTour team can mean around 5,000 items of various pieces of kit (including socks, gloves, hats etc) each year, plus the ever increasing financial commitments to a team, all of which have to ...
How do the different gears on a bike work? ›Gears are changed on the cassette (a set of sprockets on the rear wheel) by the rear derailleur. This shifts the chain up or down the cassette. As the derailleur moves to change gear it forces the chain against ramps or steps, moving it onto a bigger or smaller sprocket.
What gear should my bike be in on flat? ›
The middle gear is ideal for regular or flat terrain when cycling. It provides a little bit of resistance without making it overwhelmingly hard to pedal. For a smooth ride on a flat road, you should combine the middle chain ring with one of the middle gears on the rear cassette.
How fast can you go on a 21 speed bike? ›A 21-speed bike can go as fast as 44 mph (70 km/h). But that requires a fit rider and a light bike with good gear ranges.
What does the H and L mean on a bike? ›You need to adjust the high (H) and low (L) limit screws on the derailleur. Viewed from behind the bike, the H screw limits how far the derailleur can move to the right, while the L screw limits how far the derailleur can move to the left.
Do you shift gears while pedaling? ›Pedal slightly easier while shifting
While you are shifting gears, you must keep pedaling in order for the chain to move from one gear to the next. When you're in a particular gear and pedaling, the chain is pulling on the teeth of that gear.
Low Gear. The low gear is the "easy" gear and is primarily used when climbing. The low gear is the smallest chain ring in the front, and the largest cog on the rear cassette. In this position pedaling will be easiest and the least amount of force will be required to push the pedals.
Which gears are high and low on a bike? ›The lowest gear is when the chain is on the smallest cog on the front and the largest cog on the rear. The highest gear is when it's hardest to pedal, this will move your bike at a fast speed if cruising along on the flat.
What gear is which speed on a bike? ›Motorcycle gear changing tips
- Remember, neutral (i.e. no gear) is between first and second gear either going up the gearbox or back down, so your input between these gears needs to be quite direct so as not to catch neutral. - As a general rule, on a low capacity bike, 1st gear for up to 10mph, 2nd for up to 20mph.
Even the phrase “21 speed” is a little deceptive.
Yep, well what it really means is that you have a choice of 21 different gears when cycling. You can pick any one of these gears at any time, and it will either make pedaling on the flat or up/down a slope easier or more difficult at that moment.
| Age | Average Speed – km/h | Average speed – mph |
|---|---|---|
| 20 – 25 | 30 | 18.6 |
| 25 – 30 | 35 | 21.7 |
| 30 – 35 | 33.5 | 20.8 |
| 35 – 40 | 30 | 18.6 |
Power, which is measured in watts (W), represents energy output over time. When you're cycling, the energy you output from your body is what propels the bike forwards. At any given point on your ride your power number (e.g. 250W) is snapshot of the work that you're putting in on the bike at that very moment.
Which derailleur to adjust first? ›
In a nutshell, adjust the front derailleur first, then the rear.
What does FL mean on a bike? ›Harley-Davidson FL is a model designation used for Harley-Davidson motorcycles since 1941, when F referred to the new large capacity 74 cui (1200cc) variant of the V-2 Overhead valve engine (″Knucklehead″) that was introduced in 1936 as Model E with 61 cui (1000cc).