What is Tire: Definition and 184 Discussions

A tire (American English) or tyre (British English) is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, which also provide a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, that is designed to match the weight of the vehicle with the bearing strength of the surface that it rolls over by providing a bearing pressure that will not deform the surface excessively.
The materials of modern pneumatic tires are synthetic rubber, natural rubber, fabric and wire, along with carbon black and other chemical compounds. They consist of a tread and a body. The tread provides traction while the body provides containment for a quantity of compressed air. Before rubber was developed, the first versions of tires were simply bands of metal fitted around wooden wheels to prevent wear and tear. Early rubber tires were solid (not pneumatic). Pneumatic tires are used on many types of vehicles, including cars, bicycles, motorcycles, buses, trucks, heavy equipment, and aircraft. Metal tires are still used on locomotives and railcars, and solid rubber (or other polymer) tires are still used in various non-automotive applications, such as some casters, carts, lawnmowers, and wheelbarrows.

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  1. F

    Acceleration of stone caught in tire tread

    1) Problem Statement: A car travels forward with constant velocity. It goes over a small stone, which gets stuck in the groove of a tire. The initial acceleration of the stone, as it leaves the surface of the road, is (A) vertically upward (B) horizontally forward (C) horizontally backward (D)...
  2. Mantikore

    Rolling resistance, tire tolerance, gas mileage

    A question in regards to rolling resistance. Am I wrong in thinking that not everything you hit on the road with your tire effects your gas mileage? Don't tires have a tolerance in terms of how much energy they can absorb before it effects your traction, therefore effecting your gas mileage...
  3. Mantikore

    Work Debate: Does a Tire Do Work on a Quarter?

    I have a question about work. In a lil debate over something related to work.. and my question is, if a car runs over a quarter laying flat on the ground, will the quarter being doing work on the tire? I say yes.. because when the tire rolls over the quarter, it is putting force on the quarter...
  4. N

    How can I simulate a rolling non-rigid tire with obstacles using ANSYS 14.5?

    Urgent help required! I need to simulate a rolling non-rigid tyre on a ground with obstacle(s). How should i proceed with ansys 14.5? Any help will be deeply appreciated.
  5. D

    Tire stuck in mud - energy conservation

    Rg. Without air resistance, show the maximum height snow can reach is h_max=R+v^2/(2g)+gR^2/(2v^2) Solve using conservation of energy How do I start this problem? I assume all the initial kinetic energy ((mv^2)/2) from the spinning of the tire is translated to the gravitational potential energy...
  6. K

    What is the diameter of the bicycle tire?

    Homework Statement A bicycle tire rotates at 30 radians/s. If the bicyclist travels at 10 m/s, what is the diameter of the tire? Homework Equations I found; for angular speed, w=v/r and for linear speed; v=rw where v=m/s and w=radians/s So if i am thinking correctly, i already know my angular...
  7. L

    A rotational tire and tape problem.

    Homework Statement A tire is rolling along a road, without slipping, with a velocity v. A piece of tape is attached to the tire. When the tape is opposite the road (at the top of the tire), it's velocity with respect to the road is Homework Equations v=ω×rThe Attempt at a Solution Well the...
  8. E

    Physics car tire throwing competition

    1. in a tire-throwing competition, a man holding a 23.5 kg car tire quickly swings the tire through three full turns and releases it, much like a discus thrower. the tire starts from rest and is then accelerated in a circular path. the orbital radius "r" for the tire's center of mass is 1.10 m...
  9. E

    Shear stress on a tire from a puddle of water

    Homework Statement A car is moving at 65 mph and hits a puddle of water 1 inch deep. What is the shear stress on the tire from the puddle of water if the radius of the tire is 16 inches. r = 16 inches u = 65 mph y = 1 inch mu = viscosity = 2.344*10^-5 lbf*s/ft^2 Homework Equations angular...
  10. S

    Car Tire Wear and Odometer Accuracy Calculation

    Even numbered book problem Homework Statement A person goes for a drive, and after, measured by the odometer, reads 37.35 miles in length. This person then replaces the tires with new ones and goes for the same drive, however, now the odometer reads 36.68 miles. Obviously the new tires are...
  11. L

    Do I Need a New Tire? - Check Tire Wear at 40K Miles

    When I got an oil change at my car dealership, I was told that my car needed new tires. I've had them since I got the car 40,000 miles ago. They said that they were "in the red", which I took as meaning they needed to be changed immediately. Well, when I got the car home, I looked at the tires...
  12. E

    MHB Solving Tire Nail Height & Distance Problems: Grade 11

    8) The diameter of a car's tire is 52cm. While the car is being driven, the tire picks up a nail. a) Draw a graph of the height of the nail above the ground in terms of the distance the car has traveled since the tire picked up the nail. For this part, I drew a graph with the max 52, the mid 26...
  13. G

    Tire Lug Wear: Understanding Flat Lugs on New and Worn Tires

    Hello! I have some basic questions about tire surfaces..specifically the lugs and I wonder if anyone can help. They are: 1) On a new tire, are the lugs flat? 2) On a worn tire, are the lugs flat? I understand there are a variety of different tire wear conditions that can affect the...
  14. D

    Lumped tire model : bristle deflection

    Hi, And thank you for your time! :) I've been studying and coding for more than a month on a physics engine for car driving simulation. Right now, I'm trying to change the whole tire model currently based on Pacejka for a more advanced one. After quite a lot of reading on the topic, I decided...
  15. C

    Tire pressure changing due to temperature

    Homework Statement Before embarking on a car trip from Michigan to Florida to escape the winter cold, you inflate the tires of your car to a manufacturer-suggested pressure of 33.5 psi while the outside temperature is 26.1 °F and then make sure your valve caps are airtight. You arrive in...
  16. S

    Car cornering: side force between external and internal tire

    Hi all, During steady state cornering which tire of the same axle experiences the higher side force? I believe the external one for higher normal load due to the weight lateral transfer. Is it true?
  17. marellasunny

    Experimentally determining tire friction coefficient

    In a recent lecture,I learned that the friction coefficient "mu" between the tire and road surface is determined experimentally by using a graph. i.e a graph between the longitudinal tire force and the longitudinal slip. Well,how did engineers emperically arrive at such a graph in the first...
  18. S

    Motorcycle cornering force on each tire?

    Thanks to anyone who cares to read or respond. I've never taken a physics class so really all I have is "it seems to me". But I would like what seems to me to make sense. Scenario. I have a motorcycle, in a steady-state corner(a circle), say 40 feet in diameter. And motorcycle is traversing...
  19. L

    Mastering Physics: Rolling Motion, Pebble stuck in a Tire by Static Fr

    Homework Statement A 1.2 g pebble is stuck in a tread of a 0.76 m diameter automobile tire, held in place by static friction that can be at most 3.6 N. The car starts from rest and gradually accelerates on a straight road. How fast is the car moving when the pebble flies out of the tire...
  20. L

    Archived Rolling Motion, Pebble stuck in a Tire by Static Friction

    Homework Statement A 1.2 g pebble is stuck in a tread of a 0.76 m diameter automobile tire, held in place by static friction that can be at most 3.6 N. The car starts from rest and gradually accelerates on a straight road. How fast is the car moving when the pebble flies out of the tire tread...
  21. G

    Pebble flung from tire problem

    Homework Statement A car whose wheels are of radius r feet is driven at a speed v. A pebble is thrown from one of the wheels. A. Neglecting air resistance, find the max height above the roadway which the pebble can reach as a function of r, g, and v. B. For very small values of v, what does...
  22. P

    Performance vs tire dimensions

    I would like to know what effect does tire width and tire diameter has on performance or overall efficiency of a vehicle.
  23. S

    Can US Tire Warmers Be Used in Australia Without a Transformer?

    Hi everyone, stumbled across this forum in my quest for answers regarding my tire warmers Righto I purchased some pretty flash tire warmers for my 1198s ducati from the US I saved a heap. I bought them with the intentions of buying a step down transformer (240V to 120V 2000W), I have made some...
  24. A

    Difficulty in analyzing automotive tire in workbench

    Hi, I am trying to analyze the effects of pressure on the automotive t=ire by modeling and simulating the same in ANSYS workbench. However, I am having trouble applying material conditions to the model. I wish to use mooney rivlin material but when I apply that based on the guidance given by...
  25. Feodalherren

    How does tire pressure affect contact area?

    Homework Statement Your right rear tire normally has to support a weight of 3000N. The contact area of your tire with the road is 200 square cm. If the pressure in your tire is suddenly reduced from 32 pounds psi to 16 pounds psi, what must be the new contact area to support the car...
  26. L

    Real life tire mark analysis; help me prove I'm innocent

    I am hoping you all could help me. I have been accused of a felony based on these tire marks. I did not make these marks! I do not even think my truck is capable! I am wondering if there is a way for the law of physics to prove this. I am posting all of the information I have that I thought...
  27. F

    Cannot find any scientific validation of product Dyna Beads for tire balancing

    Cannot find any scientific validation of product "Dyna Beads" for tire balancing. I'm intrigued by the difficulty in locating any reputable scientific analysis of this method. Google "Dyna Beads". Primary vendor of these tire balancing beads is the following company...
  28. M

    Need to support horizontal spinning tire: turntable or thrust bearings?

    Hi everyone. I need to create a mechanism involving a 12" diameter horizontal tire, spinning at 3000RPM, with 2kg mass. The wheel will be attached to a spinning shaft. The only thing, I need to support the wheel from the bottom using flat bearings of some sort, so it can spin freely...
  29. A

    Help needed for this question - Air pressure in a bike tire

    Help needed for this question -- Air pressure in a bike tire Homework Statement The Pressure gauge on a bike pump reads 8 bar at sea level on a day when the temperature is 21°C. Assume that the gas constant for air is 286.9 J/Kg K a) What is the density of the air in the tyre? b) What is the...
  30. M

    Adiabatic Process: Burst Tire & Cloud Formation

    how is the rapid escape of air from a burst tyre and cloud formation in atmosphere an example of adiabatic process? please explain
  31. T

    Determining spring constant of a tire

    Homework Statement We are modeling the behavior of a sack truck when driven over a small step. Afterwords we will do some tests with an actual sack truck to verify the model. The movement will be modeled simply like a spring-damping system only having one spring and one damper, thereby...
  32. E

    Center Cap vs Tire Diameter Rotation

    Hello all, Just trying to find a formula and need some help. If a tire is 22 inches in diameter, what are the RPMs of the outer diameter of a 22 inch tire versus the RPMs of the outer diameter of a 2.5 inch center cap, on a car traveling 30 MPH? Are they the same, or are the rotations of the...
  33. N

    How to model a system made by a vehicle suspension and tire?

    Hello everybody, Im trying to model a system made by a suspension and a tire for a vehicle simulator written in c#. I modeled both the suspension and the tire as a spring and a damper. So the model is formed by a spring and a damper in parallel (the suspension) in series with another spring...
  34. E

    Uniform Circular Motion Bicycle Tire

    Homework Statement A spot of paint on a bicycle tire moves in a circular path of radius .33m. When the spot has traveled a linear distance of 1.66m, through what angle has the tire rotated? Homework Equations v=rw w=2∏/T The Attempt at a Solution 1.66=2∏/T 1.66T=2∏ 100∏/83
  35. J

    How does traction compare to the width of a tire?

    Please help settle this argument I had with a friend. We both have fast FWD cars, and on road courses we both have problems with oversteer (where the back of the car slides out on corners). He says if I put wider tires on the rear of my car, I will have less oversteer. My understanding of...
  36. S

    Comparing pressure of air in a tire installed in a car & a free tire

    Imagine an ordinary car wheel with rubber tire, installed in a car axle. So the weight of the car (some of the weight of course, because there are 4 wheels) is pressing on it. Let's denote this pressure of the air in the tire as P_{c}. Now the same wheel (with its rim and tire) remove from...
  37. C

    Revolutions of a tire and angle in radians thru warranty

    Homework Statement The tires on a new car have a radius of .275 meters and are warranted for 75,000km a)what is the angle in radians that one of these tires will rotate thru in the warranty period? b) how many revolutions does this make?Homework Equations 1rev = 2pi radians circumference =...
  38. Z

    How Does Pumping Air Affect Bicycle Tire Pressure and Temperature?

    Homework Statement A bicycle tire is to start with flat and has a pressure of one atmosphere. It is then pumped such that the pressure is 4atm, when the air inside the tire has the same temperature as before. a) How much air has been pumped into the bicycle tire? b) What is the temperature of...
  39. S

    Automotive Tire Coefficients of Friction (Mu)

    Do any of you know just a general range of friction coefficients for tires? I'm working out some braking problems, but can't really find anything searching online.
  40. C

    Vehicle Lateral Force Effect on Tire Wear

    Hello, Just to check if anyone is able to help on this: As we generally know, lateral force on vehicle is also more commonly known as cornering force. In a situation where all external parameters are kept constant, i.e road temperature, road surface friction coefficient, same exact tire...
  41. D

    Motorcycle tire circumference change with lean angle and acceleration

    Hello, First of all - I love this forum - so many interesting topics! My question is quite complicated - at least for me. My high level goal is to measure lean angle based on the difference of speeds between the front wheel of the bike vs the 'real speed' (let's just assume I have the...
  42. M

    Force (F) & Torque on Tire: Visual Explanation

    Please look at picture for details... Is the reason why Force (F) does not create a torque when applied at the given point on the tire because it is pulling against the axis with a Force (F) towards the right and at the same time the axis pulls back with an equal force magnitude but opposite...
  43. J

    Calculating Molecules in a punctured tire

    If a tire is punctured (or if any container full of air is holed) the air starts to leak out. Consider a small area A of the wall of the container. Show that the number of molecules striking this surface in a time interval Δt is pAΔt/2m<Vx> p is the pressure m is the average mass of the...
  44. H

    Filling Flat Tire - Adiabatic Reversible Process

    Homework Statement A nearly flat bicycle tire becomes noticeably warmer after it has been pumped up. Approximate this process as a reversible adiabatic compression. Take the initial P and T of the air (before it is put into the tire) to be 1.00 bar and 298.0K. The final volume of air (after it...
  45. I

    Pressure rise due to heat in a tire

    I am not smart enough to know the answer to this question. My son is being accused of touching a bike yes touching on the seat a bike on a bike rack which the school is claiming made both tires pop. The only way i see this as possible is if the bike owner aired the tires up in the morning around...
  46. M

    Circular motion bug on tire

    Homework Statement At takeoff, a commercial jet has a speed of 60.0 m/s. Its tires have a diameter of 0.850 m. (a) At how many rpm are the tires rotating? (b) What is the centripetal acceleration at the edge of the tire? (c) With what force must a determined 10-15 kg bacterium cling...
  47. A

    Thermal - why check tire pressure when it's cold?

    Homework Statement Why should we check pressure in a tire when the tire is cold? Homework Equations ... The Attempt at a Solution After Googling around, I found a statement saying that when a tire is "cold," it means that it is at 'room' temperature, or the surrounding air in this...
  48. E

    Street tire static and kinetic friction coefficients?

    Anybody know where I can find data on normal street-tire friction coefficients on dry asphalt? I'd like both the static, and the kinetic coefficients. If not, can somebody give me a range of reasonable values? While I'm at it... What about racing slicks on asphalt? I found one source...
  49. K

    Normal distribution: tire durability

    Homework Statement The top-selling Red and Voss tire is rated 60000 miles, which means nothing. In fact, the distance the tires can run until wear-out is a normally distributed random variable with a mean of 75000 miles and a standard deviation of 5000 miles. A. What is the probability...
  50. C

    How Do Tractive Forces and Rolling Resistance Affect a Car Wheel's Motion?

    Diagram = http://i.imgur.com/LaUO4.jpg The tire is powered by a motor of torque T. It's weight is W and the static friction force is Fs. Consider that the tire is moving upwards in a constant speed of V. I would like to understand the relations between forces on a model like above. Also how...
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