Variable speed bikes: 21 speeds, 24 speeds, 27 speeds. Where is the difference? What s the differenc

The number of wheels in the front and rear wheels is different. The 21-speed is generally three wheels in the front and seven wheels in the rear, and 3 times seven can combine 21 shifting combinations, ......and so on

The more gearing combinations there are, the more adaptable they are to various road conditions, and the more expensive they are generally priced at.

Generally, the smaller the front wheel, the larger the rear wheel, the more labor-saving it is to pedal, but the slower the speed, suitable for mountain, mud, sand, uphill and other ground with high resistance. The larger the front wheels, the smaller the rear wheels, and the more laborious it is to pedal, but the faster the speed, the more suitable for smooth and flat roads such as highways and cement roads.

Variable speed bikes are different from: chain discs (or gears). 21 speeds:

The first three and the last seven, three seven twenty-one, that is, twenty-one speed change methods. 24 speed: that is, the first three and the last eight, three eight twenty-four, that is, twenty-four speed change methods.

27 speed: the first three and the last nine, three nine twenty-seven, that is, twenty-seven speed change methods.

The difference between the 21-speed, 24-speed, 27-speed shift bike is that they have different gear ratios.

The gear ratio refers to the ratio between the front gear and the rear gear.

The 21-speed bike has a gear ratio of 3:6:4:7:5:6:4:3 and a total gear ratio of 21x.

The gear ratio of the 24-speed bike is 3:6:4:7:5:6:4:3:2:5:4:4:3:2:5:4:3, and the total gear ratio is 24 times.

The 27-speed bike has a gear ratio of 3:6:4:

4:3 with a total gear ratio of 27x.

So, the difference between the 21-speed, 24-speed, 27-speed is that they have different total gear ratios, that is, they have different speeds.

Bike 21-speed 24-speed 27-speed difference:

First, the type of transmission is different:

There are 21 shifting combinations for the 21-speed, 24 shifts for the 24-speed and 27 shifts for the 27-speed.

Second, the number of chainrings of the rear flight is different:

The number of chainrings is 7 for the 21-speed rear flight, 8 for the 24-speed rear flight, and 9 for the 27-speed rear flight.

3. Flywheel: 1. The flywheel is fixed at the right end of the rear axle with internal thread screwing, maintains the same plane with the sprocket, and is connected with the sprocket through the chain to form the driving system of the bicycle. In terms of structure, it can be divided into two categories: single-stage flywheel and multi-stage flywheel.

2. The single-stage flywheel, also known as the single-chain wheel flywheel, is mainly composed of coats, flat blocks and cores, jacks, jack springs, washers, wire blocks, steel balls and other parts.

3. The multi-stage flywheel is based on the single-stage flywheel, adding several flywheel pieces, which are combined with the sprocket on the central shaft to form a variety of different transmission ratios, thus changing the speed of the bicycle.

1. The transmission ratio is different. 21-speed maximum gear ratio, minimum gear ratio 1; 24-speed maximum gear ratio, minimum gear ratio.

2. The speed is different. The larger the gear ratio, the greater the power output, and the faster the speed, for example, the gear set selected with a speed ratio of 3 is the number of chainrings in front divided by the number of chainrings selected in the back is equal to 3.

Main components: 1. Body part: including frame, fork, handlebar, saddle and fork assembly, etc., which is the main body of the bicycle. The transmission part includes pedals, cranks, sprockets, chains, central shafts and flywheels, etc., which are pedaled by manpower, and the wheels are driven to rotate through the above transmission parts and drive forward.

2. Action part: that is, front and rear wheels, including front and rear axle parts, spokes, rims (rims), tires, etc.

3. Safety devices: including brakes (brakes), lights, bells, reflectors, etc.

21, 24, 27 refers to the bicycle's shift ratio, the front ** is 3 discs corresponding to the third gear, and the rear is 7 to 9 cassette, resulting in 21-27 speeds. The 21-speed is the least suitable for speed and regulation, and the 27-speed is the highest for speed and regulation, and the difference between the 21-speed and the 27-speed is shown when climbing, making you more comfortable and easier to exert force. The 27-speed ** is also a lot higher than the 21-speed, and the 24-speed is relatively cost-effective.

Answer the difference between 21-speed, 24-speed and 27-speed. I only know that the 21-speed is 3*7, the 24-speed is 3*8, and the 27-speed is 3*9, and the transmission choice is larger. Many newbies are also asking if the 24-speed is faster than the 27-speed.

Someone rides an old-fashioned mountain bike with an iron frame and runs behind others, and some people who know you say don't run with it, people are 27 speeds, and you can't outrun others. In fact, the speed ratio just gives riders more opportunities to choose, the speed depends on their own leg strength and endurance, as long as you have great strength, 21 speed is not slower than 24 speed!

How many miles can a mountain bike ride? Theoretically, with the same cadence, 27 to 24 is faster, and 24 to 21 is faster. But in fact, the high gear ratio pedal is very heavy, and the cadence will naturally decrease, and the cadence will decrease, and the speed will naturally decrease, and the theoretical speed cannot be reached.

Or some novices buy a car and say, my car is good, why is my car pedaling so hard, the reason is that I didn't choose a gear ratio that suits you when riding.

Let's talk about my personal understanding of the difference between 21 speed, 24 speed, and 27 speed, please advise if it's wrong:

Let's start by looking at the parameters:

21-speed chainring, 48, 38, 28, cassette, 14, 28

24-speed chainring, 42 32, 22, flywheel, 11 30 (11 32).

27-speed chainring: 44 32, 22, flywheel: 11 30 (11 32).

The number of chainrings divided by the number of flywheels is the gear ratio.

21-speed maximum gear ratio, minimum gear ratio 1;

24-speed maximum gear ratio, minimum gear ratio.

27-speed max ratio 4, minimum gear ratio.

The difference between the 27 and 24 speeds is larger or smaller than the 21 speeds, which allows you to run more and with less effort. Because the 24 chainring is not the same as the 21, a smaller chainring can get a lighter gear ratio, which is a great advantage when climbing hills. The 24-speed car can achieve the transmission ratio even when using the 2*1 speed ratio, and if the flywheel is 11 32 cars, it can reach the transmission ratio of 1, (the minimum transmission ratio of the 21-speed is 1).

Therefore, the advantage of 24-speed over 21-speed is not only in the fastest gear, but more in the slowest gear, making it easier and more powerful for you to walk on mountain roads. The average novice only wants to be faster at 24 speeds than at 21 speeds, and probably few people divide the number of teeth per chainring and flywheel to see what the difference is.

Many people buy a good mountain bike, usually just run the road in the city, ride down to and from work, and are afraid of losing, the number of days of riding in a year is limited, in fact, it is a waste of good cars. Bicycles are for people to ride, not for treasures. A good mountain bike is designed for all reason, the mountain bike itself is made for mountain roads, if there is a novice to buy a car to run the road for the city, then you can buy an urban recreational vehicle, or a road bike.

As for the 27-speed car, its flywheel is generally the same as the 24-speed, the difference is that the largest front chainring is adjusted from 42 to 44, so that the 9 speed ratios under the large chainring are larger than the 24-speed, 13 more

The difference between the 21-speed, 24-speed and 27-speed bicycles is that the variable cavity speed is different, the type of filial piety punch is different and the number of chainrings flying behind is different.

First, the type of transmission is different:The 21-speed Clever-J has 21 shifting combinations, the 24-speed has 24 shifting combinations, and the 27-speed has 27 shifting combinations. The higher the number, the faster the speed, the 21-speed is the first three gears and the second seven gears, the 24-speed is the first three gears and the last eight gears, and the 27-speed is the first three and the last nine gears.

21,24,27 refers to the bicycle's shift ratio, the front ** is 3 discs corresponding to three gears, the back is 7 to 9 flywheels, 21-27 speed, 21 speed is the least applicable speed and adjustability, 27 speed is the highest speed and adjustability, the difference between 21 speed and 27 speed when climbing is shown, so that you climb more comfortably, easier to exert force, 27 speed ** is also a lot higher than 21 speed, the cost performance is relatively high is 24 speed.

Second, the number of chainrings of the rear flight is different:The number of chainrings is 7 for the 21-speed rear flight, 8 for the 24-speed rear flight, and 9 for the 27-speed rear flight.

21-speed chainring, 48, 38, 28, cassette, 14, 28

24-speed chainring, 42 32, 22, flywheel, 11 30 (11 32).

27-speed chainring: 44 32, 22, flywheel: 11 30 (11 32).

The number of chainrings divided by the number of flywheels is the gear ratio.

21-speed maximum gear ratio, minimum gear ratio 1;

24-speed maximum gear ratio, minimum gear ratio.

27-speed max ratio 4, minimum gear ratio.

3. Say goodbye

The 21-speed is the first three gears and the second seven gears, the 24-speed is the first three and the second eight gears, and the 27-speed is the first three and the last nine gears.

21,24,27 refers to the bicycle's shift ratio, the front ** is 3 discs corresponding to the third gear, the back is 7 to 9 flywheels, 21-27 speed, 21 speed is the least applicable speed and adjustability, 27 speed is the highest speed and adjustability, the difference between 21 speed and 27 speed when climbing is shown, making the climb more comfortable, easier to force, 27 speed ** is also a lot higher than 21 speed, the cost performance is relatively high is 24 speed.

The higher the number, the faster it will be. Speed difference refers to the number of different gear ratios matched with the front and rear gears; That is, for example, the front crankset of a mountain bike is usually 3 pieces, and the rear cassette can be a piece of the wheel, so the speed ratio can be 3 times 7 equal to 21 speed, 3 times 8 equal to 24 speed and 3 times 9 equal to 27 speed. If it is enough to travel only 21 speeds, 24 speeds and 27 speeds will be much more expensive, and there is not much difference between travel.

Summary: The 21-speed bicycle is mainly used for commuting riding, suitable for relatively flat roads, 24-speed is generally used for short trips and exercise, more suitable for suburban riding, 27-speed can be used for long-distance riding, and the speed is more suitable for complex roads, but it is best to wear a helmet and protective gear when riding, try to ride in sunny weather, and slow down on unfamiliar road sections.

The speed of a bicycle refers to the number of gears, which is the combination of the chainring and flywheel of the rear wheel. The 21-speed, 24-speed and 27-speed represent the combined number of the rear wheel chainring and cassette of the bicycle, respectively, and 27. The difference between these speeds is that they offer different range of gear ratios.

The higher the number of speeds, the wider the gear ratio range, allowing for finer adjustments to resistance and speed while riding. As a result, bikes with higher speed numbers are usually better suited for professional riders or those who need to ride in different road conditions. Specifically, the 21-speed bike has a relatively small gear ratio range, which is suitable for flat roads and light uphill climbs; The 24-speed bike has a wide range of gear ratios, which is suitable for moderate uphill and undulating sections; The 27-speed chaotic hall bike has the largest gear ratio range, which is suitable for steep uphill climbs and complex road conditions.

Of course, the speed of the bike is not the only consideration, there are other factors to consider such as frame, wheels, brakes, transmission, etc.

1. The transmission ratio is different.

21-speed maximum gear ratio, minimum gear ratio 1; 24-speed maximum gear ratio, minimum gear ratio 2, different speeds:

The larger the gear ratio, the greater the output power, and the faster the speed, for example, the gear set selected with a speed ratio of 3 is the number of gear discs in front divided by the number of gear discs selected in the back is equal to 3, that is, you can step on one turn (the front gear disc turns once) and the back gear has to turn 3 times, so this is the reason for high speed gear. The 24-speed is faster than the 21-speed.

3. The advantages of uphill are different

The more speeds, the more advantageous the uphill climbs, and the 24-speed has an advantage over the 21-speed uphill.

The 21-speed is a variable 21-speed variant. Three large cranksets in the front. Behind flew seven. This is used with 21 kinds of speeds. The 24 and 27 cranksets are three.

Speed difference refers to the number of different gear ratios matched with the front and rear gears; That is, for example, the front crankset of the mountain bike is usually 3 pieces, and the rear flywheel can be a piece Then the speed ratio can be 3 * 7 = 21 speed, 3 * 8 = 24 speed and 3 * 9 = 27 speed If it is enough to only travel 21 speeds, 24 speeds and 27 speeds will be much more expensive, and there is not much difference between travel.

To put it simply, what we call 21 speed or 27 speed is the product of the chainring of the front flight and the rear flight The chainring of the front flight is generally three, and the back is more or less No matter how much speed We generally use one matching mode when riding on the flat ground, so these three shifts are basically the same and do not affect the speed Then when climbing, the difference between 21 speed and 27 speed is shown The so-called shifting is more delicate, that is, you can choose from several shifts, so that you can climb more effortless, more comfortable, more in line with your riding style.

As for the height of the saddle, the most suitable and comfortable is that the saddle is the same height as the handlebar You stand on the ground and the handlebar to the armpit Just If you require labor-saving, then you can properly pull the saddle higher The higher the person on the saddle, the greater the transmission force, the more labor-saving the relative The highest should not exceed the vehicle management cordon Otherwise, there will be an accident It is also uncomfortable The speed of the car has nothing to do with the height of the saddle The comfort of the saddle is the most important It is also related to your frame model If you have any questions, you can ask me again.