QUESTION:
How does drag affect the different types of bicycles with respect to their frames?
Contents-
Abstract
Introduction
Terminology
Investigation
Manufacturing
Type of cycles
Cycle racing and modification of bicycle frames
Abstract:
Bicycles, as well as most modes of transport, came into existence in order to ease the commutation of human society. Bicycles are still a necessity for poor people, especially those living in rural areas. Cycle riding is also now the uber-cool trend, especially in developed countries. Cycling (especially racing) is a popular game all over the world. It has its place in the Olympic games. The most popular cycling race on the planet is- Tour De France.
Image source- http://www.dailymail.co.uk
People have been trying to lessen the effect of drag while racing since the time the bicycle was first invented. They could hardly imagine that something which was not visible but can only be felt was the major barrier. The people having a vested interest in racing started looking at the problem of drag seriously. They started coming up with different types of frames to reduce drag. I plan to look at the ways drag affects different types of bicycles with respect to the frames.
The aim of this essay is to figure out the effect of drag on the different types of bicycles with respect to their frames. My investigation started with consulting multiple resources relevant to bicycle racing. To serve my purpose, I have emailed multiple companies, engineers, designers, and racing teams. After collecting enough material, I started comparing the answers and the results. I also set a couple of tests to observe the theories first hand.
Introduction:
Irrespective of the fact that human beings have invented numerous vehicles, the bicycle though only human-powered remains the most popular choice for the human race. The total number of bicycles on the planet is about 800 million, far exceeding any other vehicle. A cycle as though limited by human power is also the most energy-efficient. A cycle is not only used for commutation or racing but for fitness and touring as well.
Since the invention of bicycles with the ‘Running Machine’ in 1817, there has been a race going on to improve the security and speed of bicycles. Once, the cycles became relatively safe, the focus mostly shifted on how to improve the speed. The reason for this shift in focus is the innate competitiveness of human nature. Be it, kids, teenagers, or professional cycle racers everyone wishes to get ahead of the competition. The cycle makers do take part in this obsession and further fuel it by introducing new models, relevant advertisements, and the latest technologies.
Drag is the greatest barrier faced by every cyclist. Drag is the resistance offered by air/wind that a cyclist has to overcome in order to move forward. The drag accounts for 70 to 90% of the total resisting force a cyclist has to come to terms with. The velocity of a cyclist propelling the cycle forward would always have the limitation of human power. Thus, the aim is always to reduce drag.
As competitive cycle racing started getting popular, the cycling engineers/manufacturers and even individual racers started pondering how to reduce the drag in order to increase efficiency and speed. As expected most of the innovations came from the people/firms participating in the cycle races. In order to reduce the drag, the innovators realized that they need to make major improvements in bicycle frames. The technology and materials used in the manufacture of the latest cycles have taken enormous leaps. As we discuss the topic, professional designers, engineers, cyclists, and visionaries keep on trying to find the best/optimum ways to design bicycle frames.
Terminology-
Find below the explanation of some important terms which are a requisite for this essay-
Drag- Drag is the total resistance a cyclist faces when he tries to pedal forward. Please find below the diagram demonstrating the drag-
Friction- Friction is the resistance a surface provides to the other substance/object when the latter tries to move on it.
Aerodynamics- Aerodynamics is the study of the movement/motion of air around a solid body.
Pneumatic tires- Air-filled rubber tires.
Investigation-
I decided to investigate the following-
Manufacturing
Type of cycles available
Cycle racing
Manufacturing-
Image source- Wikipedia
Cycles when they were first manufactured, were made up entirely of wood. No need to say that those cycles were not very practical for the regular use of common folks. Drag was certainly not a major factor as in order to move forward, one has to push the ground using one’s feet. The paddles were missing in this cycle. The rider could mount the cycle only when he is moving downhill. That’s the only time he can feel the drag working against his momentum.
Image source- Wikipedia
The ‘Velocipede’ was the first cycle to contain the paddles. It was a highly risky prone cycle. It was also the first bicycle to be mass-produced. It, however, enabled the rider to paddle the cycle and experience the drag even on any type of ground. Still, the major issue with the Velocipede was certainly safety. No one was wondering about the drag a rider has to face while riding a velocipede.
Image source- Wikipedia
The ‘Roadster’ which was the safest cycle till that date with pneumatic tires was the first bicycle to be used for races. The initial races were mainly for recreational purposes. The frames of these cycles were generally made up of steel. The most interesting part is that the diamond-shaped frames used for the first time on these bicycles are still used in most cycles including the latest racing cycles.
The frames of the latest racing bicycles are made up of carbon fibers and other exotic metals like Titanium, Aluminium, etc. The frames made up of carbon are far lighter and more aerodynamic. The aerodynamic carbon frames greatly reduce drag. Due to the significant weight reduction, the rolling friction reduces too. The latest carbon frames aid the cyclist to combat the resisting drag. It is thus imperative that the research to find the best/optimum designs for bicycle frames must go on.
The involvement of these new materials allows manufacturers to use aerodynamics to their maximum effect. They can now come up with unusual curves that were not even imaginable a few years ago in order to minimize the drag.
Image source- http://www.gaadi.com
Types of Cycles with Unique Frames-
There are multiple types of bicycles available as options for the modern rider. Let us consider the effect of drag on each, one by one-
City Bicycles- Ironically though the model is called City Bicycle, nowadays it is mostly used in rural areas of India. These bicycles are mostly designed for comfort. The identifying feature of these bicycles is the raised handlebars. As it can be easily noticed that the frame over here in this type of model supports the upright body position while riding. I tried both the gents' and ladies' models. Due to the nearly straight backbone position of the rider, this position is quite comfortable. As I have tested myself the rider feels more in control of the cycle as the handle grips are relatively close to the body. Also, he/she can use the complete force of his legs while peddling. Sheer this type of riding position increases though increases the drag. The reason being the large surface area the rider’s body provides as resistance to wind. The chain cover which protects the chain from dust also increases the resistance. It is very hard to accelerate quickly in this cycle. The maintenance of the speed though is a bit easier in comparison. The materials which are generally used for these bicycles frames are steel and aluminum.
City Bike- Gents
Image source- http://www.bikesdirect.com
City Bike- Ladies
Image source- Hero Cycles
2) Road Bicycle- These bicycles are generally designed for proper concrete/cement roads. The structure of these cycles enables the rider to ride in the Obree position. The position, which was first introduced by Graeme Obree to break the world record. As I tried this cycle, I felt that though this position is quite uncomfortable it drastically reduces the surface area of the body exposed to the air/wind. This drag is thus considerably reduced in these types of cycles. The road cycles are generally recognized by their dropped handlebars. The dropped handlebars are actually quite helpful in the reduction of drag. The air friction which I felt was mainly into my face, head, shoulders, arms, and a bit on the back.
Image source- TREK
3) BMX Bicycle- This cycle is mostly used for stunts and off-road biking. As I mounted the cycle and pushed forwarded I felt a lot of drag. Probably I faced the maximum drag as I was paddling the cycle without sitting on the seat. Literally, my entire body was facing the drag.
Image source- https://www.trackandtrail.in
4) Mountain Bicycle- These types of bicycles though are excellent on rough terrain they are the worst in terms of resistance. One is better off walking during windy weather than trying to run out of breath trying to peddle this cycle. I noticed that the handlebars were straight which provides the maximum surface area to the air pressure. I tried moving downhill and could easily feel the aerial force against my chest, arms, face, and abdomen. The thick tires also do resist more in comparison to other cycles. Even the thick shock absorbers on the frame offer maximum resistance due to their thickness.
Image source- https://www.trackandtrail.in/
5) Hybrid Bicycles- These cycles were designed to provide the best of the world features. These are essentially a mix of mountain cycles and road cycles. These cycles generally feature straight handlebars but come up with slick tires. The frames are also thicker in order to maintain sturdiness. I felt that the open-chested riding position increases the drag as well as the thick triangular stem. Most of the friction, I felt was on my face, chest, and arms.
Image source- https://www.evanscycles.com
6) Racing cycle (Pro)- The latest racing cycle that we come across in major pro cycle races is nearly as aerodynamic as a modern airplane. These are tested in the same wind tunnels. As it can be noted from the picture below the biggest advantage of it is clearly the ‘Superman’ position it allows its riders to assume. This position is possible due to the raised seat and the handlebars protruding in front of the cycle. These cycles are made up of exotic materials like carbon, aluminum, titanium, etc. I was excited to try this cycle. Luckily, I came to know about a distant cousin, a cycling enthusiast who posses this expensive cycle. The cycle moved very smoothly especially on artificial turf. Due to the superman position, I have to be in, in order to ride the cycle, most of the drag I felt was on my back. The drag was far less in comparison to all the cycles.
Image source- https://www.specialized.com/
Cycle Racing- It is important to discuss a bit about cycle racing as surely this is the most important and immediate reason that the need for improvement in cycles in order to combat the drag arose. The first recorded race was held in Parc de Saint-Cloud, Paris on May 31, 1868. James Moore of England won the 1200 meter race riding with a frame made up of wood and iron tires. Racing was so risky that the term ‘breakneck speed’ was coined to refer to the injuries the rider might have to bear in case he is moving at a high velocity.
Presently there are not only multiple types of tournaments but also multiple forms of competitions. These races range from road racing, track racing, cyclocross racing, BMX bicycle racing, and mountain bicycle racing, etc. Most of these competition does have different athletes and different form of bicycles competing in it.
Image source- http://eu.ironman.com
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