Rolling friction is the friction that occurs when an object (e.g a wheel or tire) rolls. It is much smaller than sliding friction except for special cases like ice skating. It is caused by the deformation of the wheel or tire or the deformation of the ground. It depends very much on the material of the wheel or tire and the sort of ground. For example, rubber will give a bigger rolling friction than steel. Also, sand on the ground will give more rolling friction than concrete. A vehicle rolling will gradually slow down due to rolling friction - but a train running on a steel rail will roll much further than a car or truck on rubber tire In physics, friction is the non-conservative resistive force that occurs when two surfaces travel along each other when forced together. ... A driving wheel on a steam locomotive. ... Firestone tire A tire (U.S. spelling) or tyre (UK spelling) is a roughly toroidal piece of material placed on the circumference of a wheel, either for the purpose of cushioning or to protect the wheel from wear and tear. ... Sliding friction is when two objects are rubbing against each other. ... Outdoor ice skating in Austria Ice skating is travelling on ice with skates, narrow (and sometimes parabolic) blade-like devices moulded into special boots (or, more primitively, without boots, tied to regular footwear). ... Rubber is an elastic hydrocarbon polymer which occurs as a milky emulsion (known as latex) in the sap of a number of plants but can also be produced synthetically. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... Patterns in the sand Sand is an example of a class of materials called granular matter. ... Placing a concrete floor for a commercial building Installing rebar in a floor during a concrete pour In construction, concrete is a composite building material made from the combination of aggregate and cement binder. ... Vehicles are non-living means of transportation. ... Moder German Class 423 EMU trainsets meet each other There are various types of trains designed for particular purposes, see rail transport operations. ... The old steel cable of a colliery winding tower Steel is a metal alloy whose major component is iron, with carbon being the primary alloying material. ... Rail can mean: Rail tracks, see also third rail Rail transport A Railroad-related periodical For the group of birds called rails, see Rallidae For the Mayfair Games board games, see Crayon Rails For rail in electronics, see . ... A small variety of cars, the most popular kind of automobile. ... The driver of this DAF tractor with an auto-transport semi-trailer prepares to offload Skoda Octavia cars in Cardiff, Wales For further uses of the word truck, see Truck (disambiguation). ...

It is worth noting that for all vehicles that travel upon wheels (such as cars and bicycles), the sum of rolling friction and static friction is what causes the vehicle to slow when the brakes are applied. The actual force applied in braking (for example, clamps applied to disk brakes) is internal, and by Newton's First Law cannot cause a change in the vehicle's motion. Therefore the slowing is caused by contact between the road and the car's tires; the static friction force between road and tire is the "equal and opposite reaction" specified in Newton's Third Law. Rolling friction can be compared to sliding friction, as when the brakes "lock up", they slide upon the driving surface and do not sufficiently slow the car. Maximum braking force occurs when there is about 11% slip between the wheel's speed and the road - this is used to advantage in ABS braking systems, and cadence braking, a manual technique which achieves something similar. A driving wheel on a steam locomotive. ... This mountain bicycle features oversized tires, a sturdy frame, front shock absorbers, and handlebars oriented perpendicular to the bikes axis Bicycle may also refer to Bicycle Playing Cards. ... Determining the Coefficient of Friction. ... A brake is a device for slowing or stopping the motion of a machine, and to keep it from starting to move. ... On automobiles, disc brakes are located within the wheel The disc brake is a device for slowing or stopping the rotation of a wheel. ... Newtons first and second laws, in Latin, from the original 1687 edition of the Principia Mathematica. ... Determining the Coefficient of Friction. ... Newtons first and second laws, in Latin, from the original 1687 edition of the Principia Mathematica. ... Sliding friction is when two objects are rubbing against each other. ... An anti-lock braking system (commonly known as ABS, from the German name Antiblockiersystem given to it by its inventors at Bosch) is a system on motor vehicles which prevents the wheels from locking while braking. ... Cadence braking is a technique used to stop a car or other vehicle more quickly on a slippery surface. ...

Several factors affect the magnitude of rolling friction a tire generates:

• Material - Tires with higher sulfur content tend to have a lower rolling friction. This is one strategy that most hybrid car vendors use to improve fuel efficiency.
• Dimensions - rolling friction is proportional to the contact area of the tire - so a thinner tire will exhibit less friction (but also less grip) than a wider one.
• Extent of inflation - Partially inflated tires tend to suffer higher rolling friction. This may lead to overheating and may have played a part in the infamous Ford Explorer rollover accidents.
• Hard rail steels last longer but may also have lower static friction. They may also suffer fatigue cracking because the cracked area is not worn away by the passing trains.

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1) it is a known fact that the size/width of a tire DOES NOT have any effect on the friction between such tire and the surface it is rolling upon General Name, Symbol, Number sulfur, S, 16 Chemical series nonmetals Group, Period, Block 16, 3, p Appearance lemon yellow Atomic mass 32. ... The Ford Explorer is a mid-size sport utility vehicle sold mostly in North America built by the Ford Motor Company since 1991 and still in production as of 2005. ... In May 2000, the National Highway Traffic Safety Administration (NHTSA) contacted Ford and Firestone about the high incidence of tire failure on Ford Explorers fitted with Firestone tires. ... Determining the Coefficient of Friction. ... Fatigue may refer to: Fatigue (physical) - tiredness in humans Fatigue (material) - failure by repeated stress in materials Fatigues (uniform) - military uniform (BDU or ACU) Chronic Fatigue Syndrome - a medical condition Battle fatigue - also known as Post-traumatic stress disorder Readers fatigue - a side-effect of parsing poorly formatted textual... Cracking has several meanings: Cracking (chemistry) is the decomposition of complex organic molecules into smaller ones. ... Moder German Class 423 EMU trainsets meet each other There are various types of trains designed for particular purposes, see rail transport operations. ...

2) the forces at work to bring a mechanical wheeled device (bike or car) to rest are the following three types of friction: drag or air resistence, rolling friciton between the tires and raod surface, and friciton between all of the associated moving parts.

External link

• http://webphysics.davidson.edu/faculty/dmb/PY430/Friction/rolling.html