How to drive off road

 

I have a 170 4x4 and was reading the manual on off road settings and wondered about other owners thoughts and experiences.

My understanding is the rear kicks in after the front slips significantly and you need to keep the power on, backing off disengages the rear. The off road button limits power to slipping wheels so I suppose this would have the same effect disengaging the rear. I would have thought the best approach is traction control off and give it some wellie and don’t back off. While this might be a good approach on a steep hill I’m not sure how it should be driven in snow for example. It would be good to get some input here. It is worth noting I have had 3 range rovers, Jeeps, Nissan 4wd all low range mainly for getting boats off a beach so I do have a good knowledge of “off Roading” I’m trying to understand how the system works.

27 minutes ago, Grufallo said:

The off road button limits power to slipping wheels so I suppose this would have the same effect disengaging the rear

No, the car is set to limit spinning wheels by braking them to give the wheels with grip more power, it does not disengage the rear drive.
The rear will engage drive after very little slip from the front
My take is the off road button is more to keep control going downhill but someone who does understand it will probably chip in soon.

The degree of difference between the front and rear wheels depends on which Haldex unit is fitted in your car.  

 

Haldex 5 claims to pre-engage and therefore avoid any detectable slippage.  I think Haldex 4 engages within a few degrees of wheel rotation at different speeds.

 

The Off Road Button alters the ABS and Traction Control settings and enables the Hill Descent Control.  

 

The only thing I discovered about driving in snow is that the handrake switch disables the Haldex so that you can perform lovely pirouettes with the handbrake. 

Edited 17 August, 20214 yr by Schtum

Great info guys, I guess it's all trial and error. Looking forward to having some fun in the snow!

Gen 4 and Gen 5 both advertise as being predictive.

 

Wide open throttle or large torque demand with steering lock on etc should engage the rear wheels before slip is detected or certainly within a few degrees of slip.

 

This is a good video in slow motion of haldex 5. 

 

The rears are driving and back end squatting with hardly any noticeable front wheel slip.

 

 

The off road button also limits torque at low revs to help prevent wheel spin due to excess throttle input. Try it sometime. Press the button and see how little performance you have pulling away from standstill.

The explanation in the Handbook about the Off Road Button is probably the best written section. Well worth reading.