What is Bicycle: Definition and 319 Discussions

A bicycle, also called a bike or cycle, is a human-powered or motor-powered, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A bicycle rider is called a cyclist, or bicyclist.
Bicycles were introduced in the 19th century in Europe, and by the early 21st century, more than 1 billion were in existence. These numbers far exceed the number of cars, both in total and ranked by the number of individual models produced. They are the principal means of transportation in many regions. They also provide a popular form of recreation, and have been adapted for use as children's toys, general fitness, military and police applications, courier services, bicycle racing, and bicycle stunts.
The basic shape and configuration of a typical upright or "safety bicycle", has changed little since the first chain-driven model was developed around 1885. However, many details have been improved, especially since the advent of modern materials and computer-aided design. These have allowed for a proliferation of specialized designs for many types of cycling.
The bicycle's invention has had an enormous effect on society, both in terms of culture and of advancing modern industrial methods. Several components that eventually played a key role in the development of the automobile were initially invented for use in the bicycle, including ball bearings, pneumatic tires, chain-driven sprockets and tension-spoked wheels.Although bike and cycle are used interchangeably to refer mostly to two types of two-wheelers the terms still vary across the world. In India for example a cycle refers only to a two-wheeler using pedal power whereas the term bike is used to describe a two-wheeler using internal combustion engine or electric motors as a source of motive power instead of motorcycle/motorbike.

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  1. brotherbobby

    Two tourists and a bicycle - uniform motion

    Problem : I copy and paste the problem as it appeared in the text. Attempt : ##\texttt{I could make no significant attempt at solving the problem.}## The only thing I realise is that if the two tourists be A and B, A travels on the bicycle for a while, leaves the bicycle and walks. B...
  2. K

    Induction heater using Bicycle Dynamo Generator @ 24 V 60HZ Supply

    I was wondering about the possibility of Induction heater powered by Bicycle Dynamo (alternator/generator) without using any other circuit element. Which means connecting 24 V 50 to 60 HZ AC to Coil with turns around 100 in pancake shape (10 inch diameter ) and Stainless steel plate of 3 mm...
  3. L

    I Bicycle front tire wobble due to weight on the back of the bike

    I am a bit overwhelmed with your forum site. I was not sure where to post my question...Here goes- Full details…I have an e-bike. It weighs about 55 pounds. I have ridden it for the last year with a canvas bag attached to the rear flat book carrier. The canvas bag measures 19” long, 9” tall and...
  4. T

    How does tire pressure affect distance traveled by a bicycle coasting to a stop?

    Hi, I have been wondering if there is some equation which will allow me to calculate the distance and, or time, necessary for my bike to come to a complete stop knowing only the initial speed and tire pressure, without applying brakes and with negligible air resistance?
  5. C

    I Angular momentum and turning a bicycle

    Hello everyone! I've been watching the following Walter Lewin lecture, the part that illustrates my question is part 17:19 of the video Most things have made sense during this lecture, but one persistent question I have is the following: why does the bicycle tilt toward the inside of the...
  6. A

    I Conservation of angular momentum -- spinning a bicycle wheel in space

    Suppose we have a rotating body like a bicycle wheel in space away from gravity. This body stops after a while due to friction between the wheel and wheel axles. Is not the conservation of angular momentum violated?
  7. knapklara

    Simple kinematics question -- Riding a bicycle race in two different gears

    I calculated average velocity but obviously it helps nothing with this problem. I hope to get me going with these exercises once I break the ice. Thank you in advance!
  8. F

    Opening mechanism for a bicycle kickstand

    Hey Guys, I found this thread about the proper size dimension of a torsion spring for upholding a kickstand in the right position. I have to develop a kickstand for my Omnium Cargo bike. I have been thinking about using the same choice of spring type for my product, but I've also been...
  9. Delta2

    I Bicycle physics: Keeping balanced....

    So my main question is why we maintain balance easily when the bicycle has some horizontal velocity, but it isn't the same when bicycle is at rest. The best answer I could find at the web is that when the bicycle wheels rotate, essentially they form gyroscopes and gyroscopes resist the change...
  10. Z

    My model of bicycle spokes breaking

    The following equation comes from a paper by HP Gavin. LOG(stress)=-.3LOG(cycles)=4.12+.072Z where Z is the normal distribution. If you only have 1 spoke you place it in the middle of the normal distribution that is a Z score of 0. So if you have 36 spokes you divide the normal distribution into...
  11. Like Tony Stark

    Degrees of freedom of "simple bicycle"

    Hi I thought that a bike could be simply modeled as two wheels attached by a rigid bar. If the wheels move without sliding, then there is one degree of freedom: one of the wheels moves and so does the other one since they are rigidly attached by the bar. Then, if the wheels can turn to the right...
  12. H

    Friction Drive Bicycle -- Required Torque

    Hi, I am working on a project regarding the friction drive on bicycles. I would like to design an assembly which has to be compact enough, and has to be able to produce torque that will move the bicycle from a stationary position, but as it turns out with my calculations torque required is...
  13. roybot

    Motion-powered GPS tracker to install permanently inside a bicycle frame

    Briefly, the problem; stolen bicycles are notoriously difficult to recover. Designing a GPS tracker to fit on one is challenging, because bicycles rarely have their own available power source. Whatever GPS unit is used must typically have its own battery as its sole source of power, which...
  14. U

    Material properties of a bicycle

    Summary:: Please help me to determine the thickness of the material of the bicycle given, i need a step by step procedure. I know the formula required but can figure out the forces acting and reactions on the bicycle. The weight of the person riding the cycle is estimated to be 70-80kg Help me
  15. Nexus99

    Bicycle wheel forced to roll around a vertical axle

    I had some idea to solve this problem but i can't understand where the moment M is directed and where the force/forces that has magnitude ##\frac{M}{d}## is/are directed. Can anyone help me?
  16. R

    I Downhill Bicycle Braking Question

    I ride gravel bikes on steep mountain roads and on the way down I have to ride the brakes pretty hard. I want to minimize brake heat so I have always thought that keeping the bike's velocity lower on average by applying the brakes more often will reduce the amount of energy the brakes will have...
  17. S

    Bicycle gear system's Input-Output ratio?

    A person weighing 60 kg exerts 30 kg of thrust on a pedal (crank) x 2 pedals = 60 kg of force per Revolution. Let's say @ 30 RPM. What is the output kg of force per RPM on the back wheel where it meets the tar. I have all the sizes and forces, yet the correct formula eludes me. The ratio per 1...
  18. H

    Question about a bicycle wheel going uphill

    I have a question about 19 and 22.19. I am not sure what difference having a large or smaller wheel would make when pedaling a bicycle. I would assume a large a larger radius turning would require more force. 22. The correct answer is c. I think this is because point A travels a large...
  19. E

    What is the optimal power variation for a cyclist on a varied race course?

    I just thought up a little problem and wondered whether anyone could advise as to how to go about it! On a flat course, suppose a cyclist might be able to maintain 300W for around an hour. This gives a total allowed energy expenditure of ##1080t \text{ kJ}##, where ##t## is measured in hours...
  20. R

    How can I use the right hand rule to find torque in bicycle wheel rotation?

    I tried to use the right hand rule to find torque but I’m not sure to go from there.
  21. B

    Mechanics of a front wheel on a bicycle

    I am working on a project where I am supposed to find some ways to get constraints on some of the components (rim, hub and spokes) to use these for parametrization. So far I have thought that the constraint for the rim is that it can't buckle from the pre tension of the spokes (here I am...
  22. BFC

    How to Calculate Weight on Pedals from Watts?

    Summary: How to calculate weight on pedals? For example, a bicycle pedal manufacturer might say that their pedals have a max rider weight of 120kg (264lbs). First off, since the rider is sitting on the saddle, I'm not sure how this would really impact max pedal weight? Going forward, these are...
  23. VVS2000

    Bicycle and tackling inertia at higher speeds

    Thanks in advance
  24. Benjamin_harsh

    How can we pump air into a bicycle tire without opening the valve?

    How can we pump air into bicycle tire without opening the valve? I mean If valve (dunlop bicycle valve)is closed, then how pumped air going into the tire?
  25. S

    How Bicycle Wheel Rim weight changes forward acceleration?

    How much faster will a bicycle accelerate forward if both front and rear wheel rims are changed for lighter ones? Power input, size, hubs, spokes tyres, Frame etc all staying the same. I can give you any sizes and weights needed, let me know what is needed for this calculation and I’ll reply...
  26. T

    Why did my bicycle speed increase on smooth pavement while coasting downhill?

    Something occurred to me that doesn't seem to make any sense to the way I understand physics. Perhaps someone can explain it. Riding a bicycle on a descending road on very rough pavement and coasting I came to a flat and they had repaved it and it was perfectly smooth. My understanding of...
  27. C

    I Is a Single Bearing Pedal Possible for Bicycles and Motorcycles?

    I have seen motorcycles and bicycles with only one front fork and I was wondering if the mechanics would be similar enough to make it possible to manufacture a bicycle pedal that has only one bearing where the pedal screws into the crank and no shaft passing through the body of the pedal...
  28. jedishrfu

    Exotic Bicycle Designs and Engineering

    Every so often we get requests for engineering projects to work on. One common theme that I've seen is Kickstarter / Indiegogo campaigns for novelty bicycles to solve that last mile problem in urban transportation: The first time I saw the Kiffy I thought that was quite a cool design. Designed...
  29. YMMMA

    SAT physics question -- Flag on a bicycle being ridden in the wind....

    Homework Statement A girl is riding a bicycle at 15 miles per hour due north. A steady wind is blowing at 15 miles per hour from the east. A flag mounted on the bicycle will be stretched out toward the (A) west (B) south (C) southwest (D) southeast (E) northeast Homework Equations Vector...
  30. G

    Applying a force in a wheel bicycle

    Homework Statement We have a bicycle and lift the front wheel. And with the hand we apply a force of 10 N down and we turn the wheel. The wheel is 26 inches in diameter and weighs 1.5 kg. Find the angular acceleration, the torque of the net force and the angular velocity after a lap. Homework...
  31. C

    I Spinning bicycle wheel in air and letting it go

    Let's say that we have a bicycle wheel with radius $R = 25 cm$ and mass $m = 1 kg$. We spin the wheel in air so, that the tread is moving at the speed of $v_o = 50 km / h$. Then, we let it roll on asphalt, given the coefficient of static friction: $f_s = 0.9$ and kinetic friction: $f_k = 0.7$...
  32. mastermechanic

    Misc. Bicycle Design (Individual Project)

    Hello everyone, I have not been here for a long time. Now I'm here for a DIY project. Purpose: I want to design and manufacture my own road bike and ride it as soon as possible. I want to design nearly all parts on a bike except for the wheels, chain, saddle, cables, maybe shafts and bolts and...
  33. manu101

    Physics EE (Extended Essay) on Bicycle Stability

    Hello! I'm new to the Physics forums so I'm not too sure if this is the right place. But hopefully it is :) Anyway, I'm currently an IB student studying Physics at higher level and decided that I was going to do my EE (extended essay), which is about 4000 words, on physics. Since I really...
  34. Evanish

    Misc. DIY - Replacing my bicycle tire with recycled plastic

    So the rubber on one of my bicycle tires has worn out to the point it needs to be replaced, and I was thinking I'd prefer a solid tire this time. Rather then buying one like a normal person I was thinking if I could make my own out of recycled plastic. Here is the plan as it currently...
  35. D

    I Static analysis of bicycle frame - Need some clarification

    Hey, I am interesting in analyzing a bicycle's frame statically from a vertical fall of x metres, this after using the energy principle i get that the force F = mv^2/r, where v = sqrt(2*g*h), r is the deformation of the bicycle at its contact point and m is total mass from the cycle and cyclist...
  36. Fernando Calvario

    Riding a bicycle around a tree w/ constant acceleration

    Homework Statement African baobab trees can have circumferences of up to 43.0 m. Imagine riding a bicycle around a tree this size. If, starting from rest, you travel a distance of 162 m around the tree with a constant angular acceleration of 5.00 × 10–2 rad/s2, what will your final angular...
  37. M

    I Can a bicycle be tipped over by only applying rear brake?

    Let's say I'm riding a bike at constant speed. Also assume that the person riding is rigid, no moving of the persons body, constant center of gravity. Assuming that there is sufficient friction between the tires and road. If I apply the front brakes, I will likely tip over. If I apply the...
  38. M

    Why do bicycle gears make pedaling easier or harder?

    Hello, I'm trying to get a conceptual understanding of why switching gears makes pedaling easier or harder. I think I understand what's happening with the rear gears, but I'm not sure I understand what's going on with the front gears. I will outline my thinking: Let's suppose our bicycle has...
  39. S

    Conservation of Angular Momentum and a Spinning Bicycle Wheel

    A person standing on a stationary friction-less turntable spins a bicycle wheel with the rotation axis of the wheel in the horizontal direction, thus the initial angular momentum is in the horizontal direction (x - axis), say to the right. Now suddenly the person turns the axis of rotation of...
  40. S

    I How fast do you need to cycle to simulate bicycle tire inflation

    My question comes from a moment when I was riding my bike. I had a flat tire. My question then was how fast do i need to cycle so that i don't ride on my rim's anymore. I tride calculating this with the force that i put on the tire (15kg+70kg= mass of the bike and I)*g= 833,85 N that devided by...
  41. A

    What is the equation for kinetic energy of a bicycle?

    Homework Statement How did they get mv^2? Where did the 1/2 go? I tried working out the equation below the question and I ended up getting (1/2)mv^2. Look at the image to see. It's the rotational kinetic energy formula. Homework Equations It's in part 1 The Attempt at a Solution It's in part 1
  42. Wrichik Basu

    B Balancing a bicycle that is moving fast, rather than one that is moving slow

    Why is it easier to balance a bicycle that is moving fast, rather than one that is moving slow?
  43. A

    Circular Motion of bicycle wheel

    Homework Statement A bicycle wheel has a radius of 0.5 m. When it spins, it completes one full turn in 1.6 s. Two identical rocks are stuck on the wheel at a radius of 0.4 m and 0.2 m. What is the ratio of the force on the outer rock to that of the inner rock? Homework Equations F=ma F=mw^2r F=...
  44. V

    How to count the bicycle wheel revolutions by accelerometer

    Hi, I am setting the accelerometer (BMA250E) on the bicycle wheel hub. I want to count the wheel revolutions(each sine wave) but the Speed over 20km the x-axis(a) data will increase. My question is: How to count the sine wave when x-axis sine wave position move to high or low. Thanks.
  45. A

    Alternative approach -- Bicycle on a curve

    Homework Statement A bicycle of mass m is traveling at constant speed v around a curve of radius r without slipping. You can take the acceleration due to gravity as g. Calculate the angle of tilt, θ, that will enable it to balance. Homework Equations R=mg Rsintheeta (Length)=Fcostheeta...
  46. D

    Bicycle tire width vs. pressure for identical comfort

    Here is what I want to know specifically: if I replace my 5cm wide rear tire with a 6.25cm wide tire, how much can I increase the inflation pressure to obtain the same comfort? I realize "comfort" is not a quantifiable measurement, maybe shock absorption characteristics is better. Perhaps it...
  47. Worthatry

    Freewheeling bicycle and friction

    Background question: A bicycle and rider have a combined mass of 75 kg. They freewheel down a slope whose maximum height is 6 meters above sea level. The slope is 20 meters long. At the end of the slope, the bicycle and rider are traveling with a velocity of 10 m/s. Calculate the work done...
  48. tranvannhancu

    Problem finding the total kinetic energy of bicycle system

    I've been working on this problem for a while and here comes the problem: I'm building a balancing system for a bicycle using Gyroscopic effect (take a look at Figure 2 for more details). My system consists of 2 parts: the bicycle itself a flywheel on top of it All parameters are given. The...