How bikes work and what to know

The bike is probably familiar to you, right? However, do you really know how bikes work? Are you ready to find out? Do not miss this helpful article.

If you had to choose the greatest machine of all time, what would it be? The phone? You might as well say it must be the computer. But for its sheer simplicity, why not the bike? There is no denying that bikes are a perfect example of how scientific ideas can be harnessed in a very practical piece of technology.

At the present age, bicycles are used by millions of people worldwide, even though they have been around for a long time. Many people cycle for exercise, some use their bicycles to get to work while others use them to deliver goods. Even dogs, there are professional bike races for entertainment purposes. Biking seems easy to many people, but how a bike works is actually very complicated.

How bikes work

A bicycle is put together from many parts that are essential for it to function properly. This article will cover how the following parts work:

  • Bicycle frame 
  • Bicycle wheels
  • Bicycle gears
  • Bicycle brakes
  • Bicycle tires
  • Bicycle handlebars 

Over the years, bicycles became less and less complicated to make them easier to build and customize. However, the above parts are indispensable for a bicycle. For the rest of the article, we will learn how the above parts work. 

How bikes work

Bicycle frame

There is no denying that a bicycle must not be damaged if someone weighing 60–80kg (130–180lb) uses it. That means the frame of a bike has to be pretty stiff. For conventional bicycles, frames are made from strong, inexpensive, tubular steel (literally hollow steel tubes containing nothing inside but air) or lighter alloys of steel or aluminum.

Many people might think that a bicycle frame made from aluminum tubes will be much weaker than a frame made from steel. That is only true if the tubes are of similar size. In fact, every bike needs to be strong enough to support a large weight. Therefore, a bicycle made from aluminum will use tubing with a larger diameter or thicker walls than a bicycle made from steel.

In fact, the frame is not simply supporting you. If you pay attention, you will see its triangular shape (usually two triangles joined together to form a rhombus) is designed with the purpose of distributing your weight.

Bicycle frame

 Although the saddle is placed closer to the rear wheel, you still tend to lean forward to keep the handlebars. The angle bars in the frame are designed to split your weight more or less evenly between the front and rear wheels.

That is really important. If all your weight is on the rear wheel and you try to pedal uphill, you will fall backward. Similarly, if the front wheel has too much weight, you will fall forward every time you go downhill!

However, the frame is not designed to be 100% rigid. That will likely make your trip much less comfortable. For most bikes, their frames are curved so that they absorb some of the shocks as you ride, although other parts much more effect on ride comfort

Bicycle wheels 

a wheel and the axis it rotates around is a good example of the “simple machine” that scientists often refer to. Bicycle wheels are typically over 50 centimeters (20 inches) in diameter, taller than most car wheels, and it multiplies force or speed depending on how you spin it. The higher the wheels, the faster they spin. That is why racing bike wheels have the largest diameter (about 70cm or 27.5 inches).

The rear wheel supports your full weight, however in a very interesting way. If the wheels are solid, they will be depressed when you are in the saddle and pushing back up to support your weight.

For most bicycles today, their wheels are made up of a sturdy hub, a thin rim with about 24 high-tension spokes. To be both strong and light and reduce drag, bicycles have spoked wheels, instead of solid metal wheels.

In fact, bicycle wheels are not as weak as they appear. Besides the number of spokes, the way the spokes are connected between the rim and its hub is also important. Since the spokes cross each other from rim to its hub, a bicycle wheel is truly a strong three-dimensional structure.

When you sit on the bike, your weight is on the axle bars. When that happens, some spokes will stretch a little longer and others will decrease a bit. 

For example, you weigh 60kg (130lb). That means there is about 30kg (130lb) pushing down on each wheel (excluding the bike’s own weight) and the spokes are what keep the wheel from warping or cracking.

Since each wheel has 24 spokes, in practice they bear uneven weight. In particular, the spokes located near the vertical are subjected to a much greater load than the other spokes when the wheel rotates.

The closer the spokes move to the vertical, the more deformation it is subjected to. The load that each spoke is subjected to increases and decreases dramatically with each revolution of the wheel. After thousands of such cycles over and over again, one of the spokes may fail. That causes an immediate increase in the load on the remaining spokes. As such, they are more likely to be damaged by a kind of “domino” effect. As a result, the bicycle wheel will be warped.

Bicycle gears

The gears are chain-linked so you can ride faster (going along the straight) or ride more easily (going uphill). It is also an example of a simple machine. Gears can make an amazing change to your speed. Say, with the gear ratio on a racing bike is 5:1, a single turn of the pedal would get you about 35 feet (10m) on the street.

When you ride your bike, the pedaling force you generate allows the bike’s gears to turn the rear wheel.

Bicycle gears

When the effect of friction, the tire can stick to the road surface. As a result, your bike can go in the desired direction. In fact, you can generate about 10 watts of power with a hand crank electricity generator. However, you cannot use those electricity generators for a long time without getting tired. Therefore, it is true to say that it is much easier to generate large amounts of power for longer time periods by using the calf muscles than by using the arms and hands.

That means cycling makes great use of the strongest muscles in your body.

Bicycle brakes

No matter how long you go, there will come a time when you need to stop. Bicycle brakes are what help you do it at the right time. It works by friction (sliding friction). Nowadays, you can find a number of bicycles with disc brakes. However, many bikes still use traditional caliper-operated rim brakes.

When you squeeze the brake lever, a pair of rubber blocks will clamp onto the metal inner rims of the front and rear wheels (depending on which side you press the brake). When these rubber blocks squeeze the wheel, they convert your kinetic energy into heat, which slows you down.

Compare rim brake vs disc brake:

For rim brakes, caliper-operated push on the outside edge of the wheel (where it’s spinning fastest but with the least force). As a result, they need relatively little braking force to slow down the wheels and that’s why they can be small and light.

Unfortunately, they are completely exposed to rain from above and from the side as well as water spray from the wheels. If the wheel and the brake shoe are wet, the friction force is significantly reduced (up to ten times less than in dry conditions). Therefore, it is almost impossible to brake suddenly.

For disc brakes, they work closer to the hub, thus, they need to apply more braking force than the rim brakes. At the same time, it is also heavier and more mechanically complex. However, they tend to be more effective in wet and muddy conditions. Many people prefer disc brakes because they make a bike look better. Meanwhile, others prefer rim brakes because they are so simple.

Bicycle handlebars 

The handlebar of a bicycle acts as a kind of lever. The typical use of the handlebars is for you to easily adjust the direction. However, you still have to press hard on the brake and hold that position longer to stop. The longer the handlebars, the easier it is to swivel the front wheel. However, the more you extend your arms, the more air resistance you create. That’s also why racing bikes have two sets of handlebars for cyclists to choose from. 

How bicycle handlebars work

How bicycle handlebars work

Bicycle tires 

Again, friction also comes into play in this case. It gives the tires a grip that makes it easier to control the bike, especially on wet days. Bicycle tires, like car tires, are not made of solid rubber. They are lighter and have high elasticity. As a result, they give you comfortable rides.

Different bikes use different tires. Racing bicycles, for example, have smooth, narrow tires that are designed for maximum speed. Meanwhile, mountain bikes are integrated with fatter, more robust tires.

See more:

Frequently Asked Questions

1. What are the spokes on a bicycle?

The spokes on a bicycle are thin wire-like rods that attach the rim of a wheel to the hub of the wheel.

2. How many spokes are there on a child’s bike?

There is no exact answer for that. The most common on standard bikes are 36 spokes/wheels. Some cars may have 72 or even 144. Meanwhile, a few smaller wheels may exist with fewer spokes.

 3. What are the spokes on a bicycle made of?

Stainless steel spokes are the most popular these days, but you can still find galvanized steel spokes on inexpensive bikes. Expensive bicycles may have spokes made from carbon fiber or aluminum spokes.

4. How many spokes are there on a 26-inch bicycle wheel?

This completely depends on the wheel. The most popular number of spokes per wheel is 36. Some wheels have 32. Higher performance wheels have even fewer.


All in all, it all seems like how bikes work is more complicated than you think, doesn’t it? In general, bicycles simply use momentum, force and friction and energy conversion to get us moving. Whether you are teaching physics or studying simple machines, there is a lot you can learn from this simple two-wheeled machine.


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