{"id":5705,"date":"2020-02-21T09:00:11","date_gmt":"2020-02-21T08:00:11","guid":{"rendered":"https:\/\/www.presticebdt.com\/?p=5705"},"modified":"2023-09-24T13:17:29","modified_gmt":"2023-09-24T11:17:29","slug":"what-is-rolling-resistance-tyre-model","status":"publish","type":"post","link":"https:\/\/www.presticebdt.com\/el\/what-is-rolling-resistance-tyre-model\/","title":{"rendered":"\u03a4\u03b9 \u03b5\u03af\u03bd\u03b1\u03b9 \u03b7 \u03b1\u03bd\u03c4\u03af\u03c3\u03c4\u03b1\u03c3\u03b7 \u03ba\u03cd\u03bb\u03b9\u03c3\u03b7\u03c2 \u03c3\u03c4\u03b1 \u03b5\u03bb\u03b1\u03c3\u03c4\u03b9\u03ba\u03ac | \u03a0\u03b1\u03c1\u03ac\u03bc\u03b5\u03c4\u03c1\u03bf\u03b9 \u03ba\u03b1\u03b9 \u03b5\u03c0\u03b9\u03b4\u03cc\u03c3\u03b5\u03b9\u03c2"},"content":{"rendered":"

What is rolling resistance in tyres<\/h1>\n

Rolling resistance: origin and design parameters<\/h2>\n

\"\u0391\u03bd\u03c4\u03af\u03c3\u03c4\u03b1\u03c3\u03b7<\/a><\/p>\n

The origin of rolling resistance.<\/h3>\n

The upright wheel rolling freely<\/strong>, that is without applying a driving torque, over a flat level surface long a straight line at zero side slip, may be defined as the starting situation with all components of slip equal to zero<\/strong>. A relatively small pulling force is needed to overcome the tyre rolling resistance and a side force and self-aligning torque may occur as a result of the not completely symmetric<\/strong> structure of the tyre.<\/p>\n

When the wheel motion deviates from this by definition zero slip condition<\/strong>, wheel slip occurs that is accompanied by a build-up of additional tyre deformation and possibly partial sliding in the patch \u03b5\u03c0\u03b1\u03c6\u03ae\u03c2<\/strong>.<\/p>\n

\"Free<\/a><\/p>\n

\\(\\begin{align*} r_e=\\frac{V_x}{\\Omega_0}\\end{align*} \\)<\/p>\n

Longitudinal slip<\/strong>: \\(\\begin{align} \\kappa=-\\frac{V_x-r_e\\Omega}{V_x}=-\\frac{\\Omega_0-\\Omega}{\\Omega_0}\\end{align} \\)<\/p>\n

where \\( \\Omega \\) denotes the angular velocity<\/strong> in traction or braking; the lateral slip is defined as \\( \\tan\\alpha=-\\frac{V_y}{V_x} \\)<\/p>\n

The parameters affecting the tyre rolling resistance.
\n<\/strong><\/h3>\n

\u00a0Newton’s first law<\/strong> says that “a body remains in its state of quiet or uniform rectilinear motion until a force intervenes to modify this state”.<\/p>\n

The motion of any body is the result of the interaction of forces acting on it. As mentioned, several times in these chapters, the movement of our vehicles also derives from the combination of a certain number of forces, which can be grouped conceptually into traction units, if they allow advancement, and resistant, if they oppose the motion of the vehicle or side.<\/p>\n

\u03a4\u03bf driving forces naturally include the traction forces exchanged between the tires and the ground<\/strong>, but also include all those external actions that cause the vehicle to move in the direction of motion (the pull due to the use of towing or recovery devices, the gravitational component on downhill sections, etc.).<\/p>\n

Resistant forces are all those actions that oppose<\/strong> the movement of the vehicle and therefore include: the rolling resistance<\/strong> of the tires, the aerodynamic resistance<\/strong>, the resistance due to the slope, the frictions<\/strong> in the transmission organs, the resistance caused by the sinking of the wheels in the ground, etc. Each of them acts with greater or lesser continuity and entity according to the conditions of use, but among them there are two that are always present<\/strong> during the movement of a vehicle: the aerodynamic resistance and the rolling resistance of which the former strongly depends from the forward speed of the vehicle.<\/p>\n

Rolling resitance and performance.<\/h4>\n

Without running into aerodynamics, treated \u03b5\u03b4\u03ce<\/a>, rolling resistance<\/strong> is the result of all the energy losses that occur during the rolling of a tire. Referring to the tire only and not to the surface of the ground, these losses are to be found basically in:<\/p>\n