Rolling resistance coefficient on sand

[jeromedynamics]

TL;DR

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

 

[Baluncore]

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?

 

[jack action]

http://hpwizard.com/tire-friction-coefficient.html

Click on Sources to get some detailed info.

 

[Lnewqban]

Interesting to see that resistance coefficient increases with tire pressure on sand.

 

[jeromedynamics]

Thanks for your reply

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

 

[Baluncore]

Try not to edit inside quotes. It makes it difficult to reply to the points.

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.

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.

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.

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.