Rolling resistance coefficient on sand

In summary,- Rolling resistance increases with tyre pressure on sand- To lower rolling resistance over sand, maximise the wheel diameter and tyre width, (but you have fixed those parameters as 37/12.5 R37), so you must use a low tyre pressure to increase the area of the contact patch.- To experiment, get some rounded bedding sand that flows, to compare with some sharp sand used for mortar. Test the slope before they flow when dry, then when wet.
  • #1
jeromedynamics
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Rolling resistance coefficient on sand tyre 37/12.5 R37
Hello I,d like to find or to calculate Rolling resistance coefficient on sand tyre 37/12.5 R37. Thanks for your help
 
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  • #2
Welcome to PF.
There are several factors here.
Why do you need to calculate rolling resistance?
What range of tyre pressure, wheel loading, driven or lazy axle?
What type of sand, stability angle, moisture content?
Vehicle velocity?
 
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  • #4
Interesting to see that resistance coefficient increases with tire pressure on sand.
 
  • #5
Thanks for your reply

Baluncore said:
Welcome to PF.
There are several factors here.
Why do you need to calculate rolling resistance?
=> to have an estimation about autonomy of a vehicle
What range of tyre pressure, wheel loading, driven or lazy axle?
The 4 wheels of a 4X4
What type of sand, stability angle, moisture content?
=>I don't know = The vehicle will be used in the South America desert
Vehicle velocity?
=>95 km/h (max 180 km/h)

Have a nice day
 
  • #6
Try not to edit inside quotes. It makes it difficult to reply to the points.
jeromedynamics said:
Why do you need to calculate rolling resistance?
=> to have an estimation about autonomy of a vehicle
Autonomy or economy? Travelling at speed over sand will be very inefficient.

jeromedynamics said:
What range of tyre pressure, wheel loading, driven or lazy axle?
The 4 wheels of a 4X4
All-wheel-drive will reduce rolling resistance because it will help prevent the tyres digging holes, bogging down, and the vehicle sinking.
To lower rolling resistance over sand, maximise the wheel diameter and tyre width, (but you have fixed those parameters as 37/12.5 R37), so you must use a low tyre pressure to increase the area of the contact patch. The tyres will be destroyed if you then travel fast over rocky ground without increasing the pressure. Reduce the total weight of the vehicle. Improve the suspension to reduce ground impact.

jeromedynamics said:
What type of sand, stability angle, moisture content?
=>I don't know = The vehicle will be used in the South America desert
You will need to investigate the sand. Windblown sand will be a problem.
To experiment, get some rounded bedding sand that flows, to compare with some sharp sand used for mortar. Test the slope before they flow when dry, then when wet.

jeromedynamics said:
Vehicle velocity?
=>95 km/h (max 180 km/h)
There are dynamic effects. At high speed you may float over the sand before it has time to flow, but if you slow down, the sand will move and rolling resistance may be greatly increased. The tuning of the suspension will be very important.

If you cannot characterise the sand, you will be unable to estimate rolling resistance, and so must assume it to be 1.00 while the vehicle still moving, before it bogs.
 

1. What is rolling resistance coefficient on sand?

The rolling resistance coefficient on sand is a measure of the force required to roll an object over a surface of sand. It takes into account factors such as the type of sand, the weight and size of the object, and the speed at which it is rolling.

2. How is rolling resistance coefficient on sand calculated?

The rolling resistance coefficient on sand is calculated by dividing the force required to roll an object over the sand by the weight of the object. This calculation can be complex and may require specialized equipment.

3. What factors affect the rolling resistance coefficient on sand?

The rolling resistance coefficient on sand can be affected by a variety of factors, including the type of sand (e.g. fine vs. coarse), the shape and size of the object, the surface area of the object in contact with the sand, and the speed at which the object is rolling.

4. How does rolling resistance coefficient on sand impact vehicle performance?

The rolling resistance coefficient on sand can significantly impact vehicle performance, as it affects the amount of force required to move the vehicle and the amount of energy needed to maintain a certain speed. A higher rolling resistance coefficient on sand can result in decreased fuel efficiency and slower acceleration.

5. Can the rolling resistance coefficient on sand be reduced?

Yes, the rolling resistance coefficient on sand can be reduced through various methods such as using tires with lower rolling resistance, reducing the weight of the object, and modifying the shape of the object to reduce surface area in contact with the sand. Additionally, maintaining proper tire pressure and avoiding excessive speeds can also help reduce rolling resistance on sand.

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