# Rolling Resistance Equations

1. May 22, 2006

### Ideologue

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 = speed

2. May 22, 2006

### Hootenanny

Staff Emeritus
As far as I am aware, rolling resistance is not dependant on velocity or acceleration is is simply given by;

$$F_{rr} = \mu mg$$

You may be better posting this in an engineering forum though.

~H

3. May 22, 2006

### Cyrus

$$P \approx \frac{Wa}{r}$$

W = weight
a = coefficient of rolling resistance

4. May 22, 2006

### Ideologue

Thank you both for your replies.

I have read that rolling resistance does increase with speed, but I have read a lot of confusing and contradicting information on this issue. That is why I now seek clarification. Engineering forum posting is a good idea.

Cyrus’, I am not entirely sure how to use your equation. I admit that I am at a very basic level and I am (due to reading pages of contradicting information from people with negative teaching ability) in a state of high confusion! Please could you explain it and perhaps state where you learned it?

5. May 12, 2011