Editing Tire (section)

=== Forces ===

* ''Camber thrust'': [[Camber thrust]] and camber force are the force generated perpendicular to the direction of travel of a rolling tire due to its [[camber angle]] and finite contact patch.<ref name=":0A" />
* ''Circle of forces'': The [[circle of forces]], traction circle, friction circle, or friction ellipse is a useful way to think about the dynamic interaction between a vehicle's tire and the road surface.<ref name="Wong">{{cite book|url= https://books.google.com/books?id=LH8wd8im13AC&q=friction+ellipse|title=Theory of ground vehicles |last=Wong |first=Jo Yung |publisher=Wiley |year=2008 |isbn=978-0-470-17038-0 |edition=Second |pages=52–53}}</ref>
* ''Contact patch'': The [[contact patch]], or footprint, of the tire, is the area of the tread that is in contact with the road surface. This area transmits forces between the tire and the road via friction. The length-to-width ratio of the contact patch affects steering and cornering behavior.<ref name=":0A" />
* ''Cornering force'': [[Cornering force]] or side force is the lateral (i.e. parallel to the road surface) force produced by a vehicle tire during cornering.<ref name=":0A" />
* ''Dry traction'': Dry traction is the measure of the tire's ability to deliver traction, or grip, under dry conditions. Dry traction is a function of the tackiness of the rubber compound.<ref name=":0A" />
* ''Force variation'': The tire tread and sidewall elements undergo deformation and recovery as they enter and exit the footprint. Since the rubber is elastomeric, it is deformed during this cycle. As the rubber deforms and recovers, it imparts cyclical forces into the vehicle. These variations are collectively referred to as [[tire uniformity]]. Tire uniformity is characterized by [[Radial Force Variation|radial force variation]] (RFV), [[lateral force variation]] (LFV), and [[Tire uniformity#Tangential force variation|tangential force variation]]. Radial and lateral force variation is measured on a [[force variation machine]] at the end of the manufacturing process. Tires outside the specified limits for RFV and LFV are rejected. Geometric parameters, including radial runout, lateral runout, and sidewall bulge, are measured using a tire uniformity machine at the tire factory at the end of the manufacturing process as a quality check.<ref name=":0A" />
* ''Rolling resistance'': [[Rolling resistance]] is the resistance to rolling caused by deformation of the tire in contact with the road surface. As the tire rolls, the tread enters the contact area and is deformed flat to conform to the roadway. The energy required to make the deformation depends on the inflation pressure, rotating speed, and numerous physical properties of the tire structure, such as spring force and stiffness. Tire makers seek lower rolling resistance tire constructions to improve [[fuel economy in automobiles|fuel economy]] in cars and especially trucks, where rolling resistance accounts for a high proportion of fuel consumption. Pneumatic tires also have a much lower rolling resistance than solid tires. Because the internal air pressure acts in all directions, a pneumatic tire is able to "absorb" bumps in the road as it rolls over them without experiencing a reaction force opposite to the direction of travel, as is the case with a solid (or foam-filled) tire.<ref name=":0A" />
* ''Self aligning torque'': [[Self aligning torque|Self-aligning torque]], also known as the aligning torque, SAT or Mz, is the [[torque]] that a tire creates as it rolls along that tends to steer it, i.e. rotate it around its vertical axis.<ref name=":0A" />
* ''Wet traction'': Wet traction is the tire's [[Traction (engineering)|traction]], or grip, under wet conditions. Wet traction is improved by the tread design's ability to channel water out of the tire footprint and reduce [[Aquaplaning|hydroplaning]]. However, tires with a circular cross-section, such as those found on racing bicycles, when properly inflated have a sufficiently small footprint to not be susceptible to hydroplaning. For such tires, it is observed that fully slick tires will give superior traction on both wet and dry pavement.<ref>{{cite web|url= http://www.sheldonbrown.com/tires.html |title=Sheldon Brown on tires |last=Brown |first=Sheldon |access-date=2008-07-01}}</ref>