What is Bike: Definition and 191 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. 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...
  2. steveZ

    I Rotation of bike riding off cliff

    When a cyclist rides off a ‘drop’ (an abrupt step in topography, ranging from a curb to a cliff), the front wheel starts falling before the back wheel, so that by the time the back wheel comes off the drop, the bike will not be horizontal. The front wheel will be lower than the back wheel by...
  3. chwala

    At what time will bike and car be side by side again - Mechanics

    Find the question below; For part (a), i used the graph to find ##t=22## For part (b), i considered the points; ##(8,20)##, ##(13.333,20)## and ##(0,0)## it follows that, Area=##\sqrt {25.454(25.454-21.54)(25.454-24.036)(25.454-5.333)}## ##\sqrt {2842.58}##=##53.31## There may...
  4. SpinnerDude

    I Calculating power output on a spin bike

    So...I have a home spin bike which unfortunately lacks the sensors of some of the more expensive models. What I'm trying to do is work out if I can dynamically calculate my power output. The spin bike itself has: - An 18kg flywheel of radius 30cm - Direct drive between the crank and the...
  5. 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...
  6. willbikeformountains

    Does MTB rider position affect bike cornering traction?

    So there's this idea in mountain biking that keeping your weight over the tire contact patch equates to more cornering traction. What I mean is instead of leaning with the bike, you lean the bike under you while staying mostly over the tires (see the right "Bike more than body" image below)...
  7. A

    Exploring Angular Momentum: Examining Earth & Bike Wheels

    Take for example earth. Earth has angular momentum about its own axis. However, if we ignore the orbital portion, the angular momentum of the Earth relative to the sun's axis is the same. Another example is the spinning bike wheel/person holding it in a chair. It has angular momentum about its...
  8. A

    Spinning Bike Wheel Example, how is angular momentum conserved?

    In the classic example of a person holding a spinning bike wheel, as they flip the wheel over, angular momentum is conserved by the person/chair spinning with 2x the angular momentum of the initial wheel. Not questioning that. However, I thought ang momentum is always conserved about a...
  9. rufusbufus

    Calculating the energy created by a bike pump that feeds a turbine

    Summary:: I have an assignment that is looking at how a bicycle pump is used to push air through a turbine to generate energy. I need to determine the energy input and energy created. I'm hoping I can get some direction on where to start. The concept is straightforward. A bicycle pump of...
  10. Siviwe Nkosana

    How to fix a quad bike handlebar starter

    I am currently facing a problem with my quad bike handlebar starter switch. When i am turning it on it does humming but it seems as if it is not getting the power to its alternator
  11. Renewable_energyguy

    Making electricity by means of my old bike

    going off the summary I want some feedback and any opinion that may improve this project, please and thank you.
  12. mec_divi

    Aspect ratio for a motorcycle tire

    can anyone tell me the method by which the aspect ratio for the motorcycle tire can be decided given that load capacity of bike is known.
  13. S

    What can I investigate regarding the mechanics of bikes?

    << Multiple threads on the same subject merged, Thread moved to the schoolwork forums, and the OP has been reminded to show more effort on their own schoolwork questions >> I want an investigation/research that is simple to experiment practically (I don't have fancy equipment. My main piece of...
  14. D

    Load analysis on a motorcross bike - need some advice

    My task is to analyze a frame's strength of a specific motorcross using different loads, and to do this i decided to focus on vertical fall from various heights, since this will probably give the largest forces on the bike. The one can also experiment with different types of landings, i.e...
  15. sam charlton

    Supercapacitors: The Future of High-Performance Energy Storage?

    Hello, what is the consensus on using super capacitors to power a 500w electric bike motor. cheap and innovative alternative to li-po batteries or explosion between thighs waiting to happen? the plan is to create something like this: i will use a 24V motor...
  16. sam charlton

    Can a 24V 30A Dimmer Switch Handle the Starting Current of a 500W 24V Motor?

    Hello, I'm currently constructing an electric bicycle using a 500w 24v motor, 2X24v 7ah batteries (maybe 4 later on). I bought a 24v 30a dimmer switch to use as a "throttle". During the intitial test (on a table, not on the bike!) It worked absolutely fine for 2 minutes, but then began to smoke...
  17. FelixLudi

    Solving Kinematic Movement Equation: Bike Acceleration

    Hi, It's my first post here on the forum and I'm just looking for an answer to a basic kinematic movement equation. This is the text of a problem: "A bike accelerates uniformly from rest to a speed of 7.10 m/s over a distance of 35.4 m. Determine the acceleration of the bike." Now, in the...
  18. R

    B Why do softer brake pads stop a bike faster?

    Why do softer brake pads stop a bicycle faster, and wear faster, and harder brake pads stop a bicycle slower, and wear slower? Thanks Much in advanced!
  19. Abdul Waheed

    Selection of a suitable engine for developing a hover bike.

    I am trying to figure out the power required to lift a hover bike that would have four propellers and would weigh around 400-500 kg. how can i select an engine and find the required shaft power, rpm, engine cc and thrust required.
  20. O

    A stuntman drives a dirt bike on a curved track....

    Homework Statement A stuntman drives a dirt bike on a curved track with a radius of 7.50 m. If he starts from rest and accelerates at 2.35 m/s2, at what time will the magnitude of the total acceleration of the bike be 5.02 m/s2? (Hint: the tangential acceleration will stay constant at 2.35...
  21. G

    Find initial velocity and acceleration of a bike

    Homework Statement A power plant operator on a bicycle is pedaling at uniform acceleration of "a", when his initial velocity "u" m/s. After 6.2s, and 9.3s, the bicycle had moved 23.5m & 39.7m respectively. Find the value of "u" & "a". Homework Equations s=ut+1/2at^2The Attempt at a Solution...
  22. T

    How to calculate resultant force for a bike pedal stroke

    Homework Statement To calculate the resultant pedal force from the variables given: Crank (degrees) measured clockwise from vertical, spindle (degrees) measured anti-clockwise from horizontal, tangent force (N) applied to the pedal surface, normal force (N) applied to the pedal surface and...
  23. R

    Mechanical energy to kinetic energy storage....?

    Can there be a system that utilizes mechanical energy to produce kinetic energy, but "storing" the mechanical energy to be used at a different time for kinetic energy? Like a bike where you pedal but don't move; that mechanical energy is waiting to be "released" by some mechanism *** exclude...
  24. MikeTownsend

    DC motor voltage recommendations for a bike and power tools

    I have been working on some projects, I build a glass grinder, faceter with a 120v induction AC motor. Its not possible to effectively change the speeds with electronic controls being a single phase motor. It is using belts and pulleys for now. So I am wanting to build several tools, rock...
  25. Y

    I How a Bike Turns: Exploring the Mechanics

    A bike turns when you turn the front wheel, and the front wheel only turns in the direction it's aligned in. The pedaling motion provides a force in the up, or +Y direction. If the wheels are aligned up, the bike moves along +Y. If the front wheel is turned 90 degrees, the bike won't move. If...
  26. K

    Bike vs. Skateboard Acceleration (downhill with no pedaling)

    Hi everyone, My roommate and I were talking about which would win in a short downhill race (with no pedaling from either rider), a bike or a skateboard. Assuming the bike stays in the same gear (2, and 4), and has a wheel diameter of 27", and the skateboard has a wheel diameter of 2.4". My...
  27. S

    B Bike Wheels: Do Different Sizes Spray Differently?

    Do different sized bicycle wheel spray differently? I was asked this question recently and have got myself confused with an answer. To expand on the question a little, when riding through mud at the same speed, which would spray the mud further, a 26 inch wheel or a 29 inch wheel? My thought...
  28. Q

    I Bike going downhill brakes front wheel

    I'm an avid bike rider and a first year physics student. A couple days ago a friend of mine told me about how his friend was going downhill on her bike, used her front brake, and went over. I would like to determine what the minimum speed for a given slope angle is for the biker to do a full...
  29. B

    What are the physics/forces behind a bike pedal?

    Hi All, I am working on a project that mounts an accelerometer to the bike pedal, and requires me to calculate the power that the sensor experiences as the bike is being ridden. However, I am having some trouble understanding the forces that the pedal/sensor experiences. Essentially, I need...
  30. ollie_craw

    Force Applied To Pedal on Bike

    Homework Statement I think that the equation for the force someone exerts on their bike pedals or the force forward is stated below. can anyone confirm this is true? Homework Equations Fapplied by rider = (weight of rider) (Radius Crank /Radius Tire) (Gear Ratio) The Attempt at a Solution
  31. ollie_craw

    Biking up a hill in different gears

    Homework Statement Hi there, I am doing a project for my physics class where I am attempting to calculate the amount of force and work required to go up a 10% grade hill in a variety of different gears and I am running into a lot of issues. I have already collected my data and have calculated...
  32. D

    Motor necessary to power a small cart

    Is a 6.5kg/cm torque motor enough to move (let.s say at 6km/h) a small go cart and a kid (total w. about 45kg)? this is the motor: http://www.amazon.com/dp/B00T48KC1Q/?tag=pfamazon01-20 PS: this is not for a homework but for a for-fun project.
  33. A

    Is it possible for "me" to make a hoverbike?

    Hi, I saw a video of a guy who made a hover and figured; hey, I should try making one too. I've a general design in my mind. His design had two propellers, one on the front and one on the rear. I wanted to make a bike with more than 2 propellers( assuming more the propellers, greater the...
  34. CK328

    Mathematical modeling of a mountain bike rear shock

    Evening all, I've recently undertaken a project where my roll is to analyse the suspension of a mountain bike. The suspension unit in question is a Rock Shox Monarch RT3. To give a brief summary: The shock uses compressed air as the spring, the pressure is adjustable via an air valve. The shock...
  35. A

    Electric Bike Motors: Size, Wire Gauge & More

    I have been reading up on electric bike motors, there are a few things regarding size and wire gauge that have me confused. I have seen disassembly videos of around 300 watt electric bike motors with planetary gears, and I can't see how anyone can push through 300 watts through the wires without...
  36. Electro Dave

    Torque specs for 6,000lb party bike

    Hi, I'm trying to figure out the minimum specs of each components of the new party bike I'll be building to make sure nothing fails prematurely, but I also don't want to over do it because of cost and weight. This is our current bike, for reference. We will use a similar design as a starting...
  37. H

    Moment of Inertia and Bike stability

    So is a Bike driver stable when the bike is running because the bike wheels has a certain moment of inertia about the horizontal axis ,which might alter(mi gets lesser) if the direction of the axis changes ? Thanks in advance
  38. K

    How can you accurately hit a trash bin while biking with an apple core?

    Homework Statement You are traveling on a bike, moving at a constant speed of 20,0 km/h. You just finished eating an apple, and you wish to pop the core into a trash bin located by a busstop.The bin is 3,00 m from the edge of the road (where you are biking). You throw it at a point 4,00 m...
  39. N

    Can a Bullet Break a Bike Chain at 6m Underwater?

    < Mentor Note -- OP has been reminded to use the HH Template and show their work in future posts... > A man fires a bullet into a swimming pool. There is a distance of 6m from the gun to the bottom of the pool. Does the bullet have enough force through the water to break an average bike chain...
  40. M

    Impact force calculation of a Full Suspension Mountain Bike

    Hello Folks! I want to find the maximum applicable force on a full suspension mountain bike and i will use this force on a FEA software structural analysis for a uni design project. This bike has a rear suspension with 400 lbs/in spring rate.Also rear wheel vertical displacement(travel amount)...
  41. Borek

    You think you know how to ride a bike?

    Fantastic :smile:
  42. Satvik Pandey

    Front flip of a bike. Conserving Angular Momentum.

    Homework Statement We model a dirt bike as a rod of mass (M) 100 kg, and length (L) 2 m to which are attached two wheels of mass (m)=40 kg kg, and radius R=0.5 m. The bike goes off a spine ramp with angle ##\phi=1deg.## to the vertical on either side (see diagram below). Our question is, at...
  43. B

    Need help creating a gasoline electric bike

    Greetings! I have been thinking about creating a Gasoline electric bike. The reason being is that good batteries are very expensive. In fact more expensive than a good quality gasoline motor. I don't want a direct drive gasoline motor do to it being less stealthy and more cumbersome running...
  44. D

    Energy from bike riding used to charge phones/laptops

    Hi, I've been thinking up a project on harnessing the kinetic energy to use for charging or powering small deviecs around the house firstly my laptop and smart phone. I have a basic idea of what I'm going to use and have some of the things needed. My idea was to use a small brushless or maybe...
  45. F

    Calculate clamp force on bike handlebar

    Hi Folks I am looking for some help in a calculation if possible. I am looking at a bike design where the handlebars are clamped in place in the stem using only 1 bolt - see the picture attached or link below for an example...
  46. Tom Clane

    Open Source Spaceframe recumbent bike build

    Okay, so I'm new to this forum, but I'm hoping I can get some help. I live in the United States, and I'm having trouble converting from metric to standard with the build plans given. I want to build the open source Spaceframe recumbent bike which the build plans can be found...
  47. R

    How much time can I save in a bike race

    Homework Statement Hi all, I race bikes in my spare time and someone asked this on a cycling forum: How much time could you save on a 40km race on a flat course, riding at 40km/h if your bike was one pound lighter. Let's say the weight of the rider and bike together is 80kg. There was a time...
  48. R

    Bike Wheel Question: Kinetic Energy Lost on Impact

    Homework Statement Bicycle wheel is at rest, and can rotate frictionlessly about a fixed axle. A dart travels at velocity v (in plane of wheel) parallel to a line that goes through the centre of the wheel. It hits the rim of the wheel and sticks. What kinetic energy, if any, is lost during...
  49. M

    Remotely Operated Quad Bike

    Hello, I am looking to modify/convert a Quad Bike and make it remotely operated and was wondering if anyone had any advice (from a Mechanical Engineering view) on where to start my research or any other advice they could think of with regards to getting the project off the ground. Any help...
  50. T

    How Does Pedal Rotation Relate to Bicycle Efficiency in Physics Labs?

    Hello, while my question is not from a textbook, it still has to do with a lab I'm creating. My lab was to view the efficiency of rotational KE of a bike's pedals to the KE of the bike itself. Using 1/2*I*ω^2 and 1/2*m*v^2 to find KE, I seemed to have run into a problem. The KE of the bike was...