Motorcycle Horsepower Vs Torque Explained!

Horsepower and torque are the two most important characteristics of a motorcycle or any other vehicle. Both these figures depend on the engine size, construction, and purpose. Though they are important, it doesn’t mean the bike must have high horsepower and torque figures to be ideal for riding. The combination of horsepower and torque figures depends on the type of motorcycle, riding style, and conditions.

Most motorcyclists are confused between these two terms: “Horsepower” and “Torque”. If you want to become an expert rider or you are looking to buy or sell a motorbike , you must be familiar with these two terms. You must learn about the differences between horsepower and torque.

Also, you must be clear about how they influence a motorcycle's performance. Continue reading this article to learn about motorcycle horsepower vs. torque, as it explains in detail the difference between the two.

Consider two motorcycles from completely different categories:

• One is a sports bike with full-body fairings superior aerodynamics, and is lightweight as well.
• On the other hand, there is a large touring bike with a wide fairing, windscreen, saddlebags, engine guards, and much more.

Looking at the size of the two bikes, the touring bike is much heavier and larger than the sports bike.

Considering their most important features, sports bikes have an average-sized engine, with a displacement of around 1,000 cc. Meanwhile, the touring bike has a large-displacement engine of around 1,800 cc.

Talking about their purpose, a sports bike is used for super fast rides and attaining top speeds. They are meant to be ridden on race tracks.

On the contrary, the touring bikes are designed for comfort. They are ideal for covering long miles comfortably . If you are planning to go on a long tour or a cross-country ride, touring bikes are the ideal choice.

If you compare the horsepower and torque figures of sports and touring bikes, you will notice a noticeable difference. The sports bike, which features a smaller engine than the touring bike, produces exceptional horsepower.

On the other hand, the large-sized touring bike with almost double the engine size than the sports bike produces less horsepower. However, the amount of torque produced by the touring bike is almost double than the sports bike.

It is mainly because a sports bike is all about high top speeds and quicker rides. Meanwhile, a touring bike has more acceleration and is expected to carry more load.

According to the definition, torque is defined as force applied at a distance from a pivot point or axis.

Formula: Torque = Force * Displacement

T = F * d

Units: T = Nm or lb-ft

If one Newton force is applied at a point one meter from the axis or pivot point, it produces one Newton meter of Torque.

Also, if one pound force is applied at a point with a foot of distance from its axis, one point foot of torque is produced.

Torque is also referred to as the rotational force.

The same torque principle is used in motorcycle engines to make them work. It is important to know how a motorcycle engine works before understanding torque.

In an ICE (Internal Combustion Engine), the combustion is the key force to make the engine work. It initiates the process of producing mechanical energy to drive the rear wheel.

A “Piston Crown” is installed inside the engine. When the combustion occurs, the piston crown is forced to move downward due to the pressure resulting from combustion.

As the combustion pressure acts on a certain area of the piston crown, it creates a force acting downward parallel to the piston rod.

Pressure = Force / Area

Force = Pressure * Area

F = P * A

This force acts on the crank pin to move it in a rotational motion around the crank axis. The force acting at the crank pin and the distance between the crank pin and crank axis, when multiplied, gives us the amount of torque produced by the engine.

The torque produced by the combustion and shaft is transferred to the crank, from where it is transferred to the transmission. The transmission then delivers the power to the rear wheel, which makes the motorcycle run at a particular speed.

Power is defined as the rate at which work is done. It can also be referred to as the work done per unit of time.

Consider “Torque” as work involving rotational motions. The horsepower will be defined as the “rate” or how fast the torque is applied or delivered in a given period.

The speed/rate at which one individual combustion cycle occurs inside a motorcycle combustion engine is different. If the cycle repeats itself at a rapid pace, the bike’s engine is said to produce greater horsepower.

The term horsepower is a combination of two different words: “Horse” and “Power.” The word ‘horse’ has been used with power for a long time when horses were the only source of locomotive power.

Meanwhile, the term ‘power’ is an integral part of it. As we all know, it means the rate at which the work is done.

Formula:

The formula of horsepower is as follows:

Horsepower (hp) = (Torque (ft-lb) * Speed * RPM) / 5252

Horsepower (hp) = (Torque (Nm) * Speed * RPM) / 9550

Referring to the example of large touring and sports bikes, the former produces greater torque. A touring bike produces more torque because of its long-stroke engine. As you can see, the touring bike has a larger engine with longer strokes.

Similarly, the distance between the crank pin and the crank axis of rotation also increases, resulting in an increased torque. This increased torque makes the touring bike more powerful and strong.

A touring bike’s engine also has a bigger piston crown, resulting in more combustion pressure. This increased combustion pressure also increases the magnitude of forces acting on the crank pin. Hence, when the force and the distance increase, the torque increases a great deal.

A touring bike produces stronger acceleration and can push you ahead with much greater force. These bikes are torque monsters. You can carry more luggage on a touring bike while going on a motorcycle tour as they can easily move more load than motorcycles with smaller torque values.

However, due to the longer distance between the crank pin and crank axis, the RPM (Revolutions Per Minute) is small. The longer piston is unable to rotate at a higher pace, which is why touring motorcycles comparatively produce low horsepower.

As in the case of sports bikes, not only are the engine cylinders small, but the piston rod or the stroke size is also smaller. As the piston crown, piston rod, and the distance between the crank pin and crank axis are smaller, the torque produced by a sports bike’s engine is much smaller than a touring bike.

However, the smaller the force produced by the combustion pressure, the smaller the rod, and the smaller the distance between the crank pin and axis, the faster it rotates. The torque is low, but the rate at which the torque is produced is much higher. This is why sports bikes move at a much greater speed and rev higher.

If you observe the tachometer on a touring bike, you will see the redline starts at around 5,000-6,000 rpm. This is the maximum limit of a touring bike. A touring bike’s engine cannot rev higher than this.

Meanwhile, if you observe a tachometer on even an intermediate-level sports bike, the rev range is much higher. It can rev at around 11,000-13,000 rpm.

The transmission has one of the most important role to play in a motorcycle. It controls the way how the power and torque is delivered to the rear wheel. Above all, the rider can manipulate the torque to attain a desired level of acceleration or speed during the ride using transmission.

Most motorcycles in the U.S. come with a six-speed transmission. To manipulate how the torque is delivered to the rear wheel, you are required to do the following:

• If you want more acceleration, you should ride the motorbike in low gear.
• On the other hand, if you want more speed, you should ride the motorcycle in higher gear.

As you must have practiced yourself, if you are supposed to overtake a slow-moving vehicle quickly, you downshift and open the throttle. This is how you accelerate quickly.

Meanwhile, if you want to ride fast at top speed, you are required to shift the biker to higher gear as you continue to speed up.

In simple words, take an example of a running person. The more force with which they push the ground backward to move ahead, the more torque they produce.

On the other hand, the ability with which the running person swings his/her legs to move faster can be referred to as horsepower.

If you love watching sports, you must have observed soccer players. They are quite muscular and strong. They ensure that they break any barrier or make their way to the finishing line. It can be said that they have better torque, which can also be referred to as Strength.

On the contrary, there are running athletes that may be skinnier but are required to run faster to win the race. It can be said thay they have better horsepower as they are required to move their muscles quicker.

It depends on what your preferences are. If you want your motorcycle to accelerate quickly and show better throttle response, having more torque is preferrable.

On the other hand, if you want your motorcycle to go faster, then better horsepower is more preferrable.

More riders want their motorcycles to have better torque as it provides several benifits. The performance benifits of having a good torque are many, including better acceleration and thrust.

Moreover, it can also help you carry more load on your motorbike for touring. A better torque will also help you climb steep hills and perform more work. 

When it comes to safety, a motorcycle having a high torque is safer than a motorcycle that can rev higher. Motorcycles having high horsepower can rev higher and have high top speeds. They are also made lighter compared to bikes with high torque.

So, when lightweight motorcycles move at top speeds, they become highly vulnerable to road accidents. It becomes difficult to control them at high speeds, especially when the rider is inexperienced.

On the contrary, having a high-torque engine installed on a motorcycle can help you in many circumstances, including safe overtaking and while riding in hilly areas. 

There are many factors that impact the fuel economy of a motorcycle. However, horsepower is a major one. If a motorbike produces a greater horsepower, it will consume more fuel.

More horsepower means the bike is converting more energy in less time, hence consuming more fuel.

There are many ways to define motorcycle horsepower and torque. However, in simple words, torque in motorcycles is the mechanism with which the work is done inside the engine. Torque can be defined as the force that makes the motorcycle engine work.

As the piston moves downwards due to the combustion phase inside the engine, the connecting road also moves downwards and exerts the force on the crank pin. This causes a rotational movement of the crankshaft around the crank axis of rotation. This is called torque.

The bigger the engine stroke, connecting rod, piston, and the distance between the crank pin and axis, the more the torque.

On the other hand, horsepower is the rate at which the torque is applied or delivered by the engine. It is the ability of the motorbike engine to continue the crankshaft rotation at a rapid pace. The more horsepower, the faster the crankshaft rotation is. Motorcycles with greater horsepower have shorter pistons, connecting rods, and the distance between the crank pin and the axis.

High torque means quick acceleration and better force with which the engine moves the motorbike and the rider. Meanwhile, more horsepower means the bike can go faster. Touring bikes and cruisers have large-displacement engines and have high torque figures. On the other hand, sports bikes have compact engines and have high horsepower figures to make them rev higher and attain high speeds.