What is Rolling resistance: Definition and 38 Discussions
Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy needed for deformation (or movement) of the wheel, roadbed, etc., is recovered when the pressure is removed. Two forms of this are hysteresis losses (see below), and permanent (plastic) deformation of the object or the surface (e.g. soil). Note that the slippage between the wheel and the surface also results in energy dissipation. Although some researchers have included this term in rolling resistance, some suggest that this dissipation term should be treated separately from rolling resistance because it is due to the applied torque to the wheel and the resultant slip between the wheel and ground, which is called slip loss or slip resistance. In addition, only the so-called slip resistance involves friction, therefore the name "rolling friction" is to an extent a misnomer.
In analogy with sliding friction, rolling resistance is often expressed as a coefficient times the normal force. This coefficient of rolling resistance is generally much smaller than the coefficient of sliding friction.Any coasting wheeled vehicle will gradually slow down due to rolling resistance including that of the bearings, but a train car with steel wheels running on steel rails will roll farther than a bus of the same mass with rubber tires running on tarmac. Factors that contribute to rolling resistance are the (amount of) deformation of the wheels, the deformation of the roadbed surface, and movement below the surface. Additional contributing factors include wheel diameter, load on wheel, surface adhesion, sliding, and relative micro-sliding between the surfaces of contact. The losses due to hysteresis also depend strongly on the material properties of the wheel or tire and the surface. For example, a rubber tire will have higher rolling resistance on a paved road than a steel railroad wheel on a steel rail. Also, sand on the ground will give more rolling resistance than concrete. Sole rolling resistance factor is not dependent on speed.
Hi,
What is the formula or methodology for finding the Crr? There are many of those tests done on the internet, but none state the procedure of calculation. I'm trying to find the correlation between tire pressure and distance and want to use Crr as one of the key factors influencing it. Maybe...
Dear all,
I have a very simple question. The rolling resistance (rr) of, say, a car, is defined as being proportional to the normal force/weight of an object. That seems reasonable:
##F_{rr} = C_{rr} \times F_N##
The coefficient C_{rr} is a constant, depending on the materials. But now a...
Say that I have a round object on a table and it is still. If I apply a force and it doesn't move the resistive force is rolling resistance rather than a frictional force right?
Now I must be able to apply forces in different amounts until it exceeds a boundary for the object to move similar to...
I have conducted an experiment which involves measurements of the velocities of a carriage moving in a straight line which has 4 polyurethane caster wheels attached to it. (The kind you can get a hardware store.) In one phase of the test the carriage is pushed at about .1 meters per second. In...
I was wondering that if rolling resistance is basically caused by slight deformation of a body, we must have formulas in place to relate it to the physical and material properties of a body. But when I went ravaging for it in library or internet, everything was experimental. I wished to know...
Homework Statement
Estimate the rolling resistance force for a 75gram vehicle with axle friction coefficient of 0.2 if the wheel is 40mm diameter and the axle 2mm diameter.
I am having trouble with applying the axle friction coefficient. I could not find a similar problem online.
Basically...
I am comparing three brands of tires to see which one provides the lowest rolling resistance and thus give the best efficiency at low speeds. I have the information of the tires such as footprint, weight (of the tire and load), speed.
How would i go about doing this ? am really stumped
thanks
Hello,
My name is Hugh Carstensen. I am a CSE undergrad at the Ohio State University.
I recently secured a position designing and assembling an automated camera-rig for digitization of archival works in the Knowlton School of Architecture.
The rig will be powered by a number of small stepper...
http://imageshack.com/a/img923/733/FJKAqj.jpg
so here is the deal. is rolling resistance N+Ft or are they "separate" in a means of: N part is for static friction = mu*N and Ft is part of rolling resitance=coefficient of rolling resistance*Ft so that in order for tire to start rolling without...
Hi! Well, I'm programming a vehicle's physics, and I have trouble finding a way to calculate Rolling resistance, though i searched a lot. I already have the Traction Force and the Drag Force, but now I need Rolling Resistance. The best thing i found is that Froll = Croll * P, where Croll is the...
Homework Statement
A transfer car moves concrete slabs.
Given values are wheel diameter D, shaft diameter d, rolling resistance FL , speed v, car weight mv , load weight mk , output power P at rotation speed n, average torque Mm , motor moment of inertia Jm , fan moment of inertia Jt and...
Homework Statement
The carriage and its passengers start at rest at A. At B, the bottom of the ride, the maximum speed of the carriage is 20ms-1. The vertical distance between A and B is 110m. The length of the track between A and B is 510m. The mass of the carriage and the passengers is...
I'm a games programmer working on a (simple, so far) physics engine for a driving game. Right now I'm interested in acceleration, and in particular trying to estimate the forces that go into it. I've got basic data for a bunch of cars (0-60 time, 0-100 time, top speed, mass) and a brute-force...
Consider a object of 5 kilos which is fixed with 4 rolling tyres (like in a trolly) which is in a slanting position of 30 degree angle.
My question:How to find the force required to move the object upwards the slope along with rolling resistance considered?
I tried the force using the F push...
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...
Hi everyone - quick question on something that's been bugging me. So, train wheels, which are solid steel, have incredibly low rolling resistance, an order of magnitude less than average car tires. This is because they don't bend significantly, so you're not wasting energy to heat as in the...
Freight train is more efficient than truck due to lower rolling resistance. And I wonder which one has lower rolling resistance, small diameter or larger one or it doesn't not depend on diameter at all? Both are steel wheel on steel rail.
We know that in real world scenarios, for rolling without slipping of bodies like sphere, dis, cylinder etc. there is a rolling resistance present. This rolling resistance comes from the fact that in actual situations bodies aren't perfectly rigid. So there is some compression at the point of...
Hi PF.
I'm currently developing a 2D platform game that is significantly physics-based using the Box2D physics engine.
However, one of my main problems right now is that the main "character" of my game is a ball and unfortunately, Box2D does not support rolling friction. The result is that...
My ultimate goal is to spec a motor for a shop tool. It is a stand to rotate a glorified pipe. The pipes are quite large (up to 19,000lbs). The pipe will sit on four wheels. Two of the wheels are motorized. I have a good idea of the torque/hp needed to accelerate to the desired angular velocity...
Hi all you physics people... we are building a high-speed robotic camera dolly here in LA for a film, and are trying to make sure we calculate our torque requirements correctly.
The maximum torque required to propel a wheeled vehicle up an incline at a given acceleration is fairly easy to...
I just want to know if I am understanding this correctly.
I am wondering what effect the rolling resistance has on the motion of a car when pushed, or when rolling to a stop. The mass of the car is 1,000kg.
I looked up on a table to find the rolling resistance coefficient of a normal car...
Homework Statement
Determine an equation for rolling resistance for a wheeled vehicle @20 mph.
Homework Equations
(1) Drr = Crr * g * m * V
The Attempt at a Solution
(2) Drr = Crr * g * m
My real question: is velocity a valid part of...
I'm calculating the rolling resistance and air drag for a 60,000 lb truck. I used a Cd=0.7 for drag coefficient; 6 m2 for frontal area; and a rolling coefficient of Cr=.008; density of air=1.3 kg/m3.
I get a force from rolling resistance of 2142 N (Cr*mass*g). I get a force from air drag at 35...
Hypothetically, if I had a sphere and a block (of the same mass and material (hence the same coefficients of static friction for both interfaces) both stationary on a surface, they would require the same force to initiate motion?
Once moving, a coefficient of sliding friction is employed in...
My zipline is 200 feet long built with 7/16" Stainless Steel Cable. Would 3/8" cable result in a faster ride with less noise from the trolley due to significantly less surface area for friction?
1) when a wheel turns there is a forward acting friction but the 'frictional' force that opposes it is rolling resistance right? So when a wheel successfully turns and move does it mean the friction is greater than the rolling resistance?
Then in a car the resisting force will be this rolling...
hi ,
I am going to design sealpress mechanism for rotary system . I need to find out how much torque required to rotate my steel roller which is connected to end of my cylinder. from wikipedia i find out rolling resistance =
The force of rolling resistance, not adjusted for...
Hi, I am a bit stuck. I am trying to work out the top speed a motorbike can reach, I have a table with bhp and torque and the highest bhp of 150 is at 9,000 rpm. I have done the following calculations:
Diameter of tyre + wheel: 0.5m
Circumfrence of tyre + wheel: 1.5707963m (round up to 1.6m)...
in the attached figure
A wheel in rolling on a surface by getting a torque about it's center(as in a car)
In this figure what will be direction of rolling resistance?
Hi friends
Let me talk in context of cars wheels...
See!, tractive force is what ground offers us depending upon the weight of wheels or particularly car. It is the maximum force that ground offers us opposite to the force we apply to ground in the form of torque(t=rxf)... if we aplly more...
I came across an interesting little problem doing some work that I though I'd share. Typically, we think of three types of resistance for a wheel:
Static Friction
Kinetic Friction
Rolling Resistance
I'm modeling the wheel of an airplane for a flight simulator. When the airplane is sitting...
Hello.
I'm trying to find the torque required of an electric vehicle to pull a 1000kg trolley on four Nylon Wheels on smooth concrete. The trolley fully supports its own weight. The vehicle has 2 rubber drive wheels of Radius( r = .125m). Now I'm not sure if am on the right track because i...
Hello, new poster here.
I have trouble understanding some friction/resistance properties and how they are applied to rolling & linear motion simultaneously.
I've done a lot of simple static / dynamic (sliding) friction examples as well as rolling without taking into account resistance, but...
A ball rolls across a table and stops due to rolling friction. It has a mass of m and travels a distance of s in the time t.
What is the ball's initial speed?
The same ball rolls until it hits a wall. It has a mass m, and traveled a total distance of s (to the wall) in the time t.
What...
Are these simple equations correct?
For rolling resistance force at a given speed:
RR = aWS
For rolling resistance force at a given rate of acceleration:
RR = aWS^2
Where:
RR = rolling resistance
a = coefficient of rolling resistance
W = vehicle weight
S =...
Is there a simple way to estimate the rolling resistance of a vehicle by rolling it down a known incline with a variety of weights?
In short, if the velocity of a vehicle rolling down a ramp is a function of the air resistance and the rolling resistence and if rolling resitence is...