Off-Road Discovery Off-Road Discovery

Geometric Limitations of Vehicle

Understand Your 4WD Vehicle Angles and Limitations



Before you start adventuring into any off-road situation you need to understand your vehicle’s “Geometric Limitations” – In reality this is just a fancy name for how and what the body shape, under body transmission and suspension parts will allow the vehicle to travel over on varied terrain while taking into account the laws of physics, dynamics and stability.

Without this knowledge there is likely to be the embarrassment of damage to the vehicle or the terrain as well as to the driver and any occupants. To keep things simple, these fundamentals are captioned photographs.

This content was developed by and owned by Paul Sinkinson, Xplorability owner. Paul is a 4wd Defensive Driver Training Consultant/Trainer and Programme Developer.

4x4 Geometric Limitations: Angle of Approach

By being aware of the following Angles and Limitations it will help you to understand more fully the capabilities of the 4wd vehicle you use.

Normally, this theory programme runs alongside full practical training and perhaps sometime in the future we can look at accompanying videos for that but in the meantime, absorb the information and step outside and check out how it applies to your vehicle.

Angle of Approach

Determines what the vehicle is able to climb up

4x4 Geometric Limitations: Angle of Approach

Angle of Departure

Determines what the vehicle can descend

Learn your 4x4 vehicle descend ability

Angle of Approach on Descent

Determines if vehicle can exit a descent

Off-Road Driver Training

Angle of Departure on Ascent

Determines if a vehicle is able to exit an ascent without connecting with the terrain at the rear

4x4 Geometric Limitations: Angle of Departure on Ascent

Ramp Angle

Determines if a vehicle can cross the centre point of a climb

4x4 driving basics: understand your ramp angle to not get stuck or cause damage

Ramp angle is also the angle at the centre lowest point between the axles

4x4 driving basics: understand your ramp angle to not get stuck or cause damage

Side Angle of Maximum Articulation

The maximum SAFE side slope angle

This is about maximum safe side slope angle while offroading

Beyond this the vehicle can rollover

4x4 Geometric Limitations: Understand your vehicles limits to prevent rollovers

Side angles are DANGEROUS – vehicle CAN ROLLOVER

4x4 Driving: close to rollover

Rear Wheel lifting off terrain – Next stage is a rollover

Overland Driving Tips: rear wheel lifting from terrain, next stage is a rollover

Beyond this point can be a rollover

4WD Vehicle Limitation: Side Angle at Maximum Articulation Before Rollover

Vehicle at rollover point

Example of a car about to rollover, check out wheel position

Front wheel is now off the ground – Rear wheel about to lift

What it looks like before a car flips over

Cross side angle at maximum articulation – DANGER!

Do not get your tires into this position off-roading, high possibility of rollover

Side angle at maximum articulation

Learn the basics of offroad driving and what NOT to do

Cross Axle Situation at Maximum Articulation

Front wheel off the terrain and opposing rear wheel also off the terrain

Overland driving fundamentals - Geometric limitations

Front and opposing rear wheels off the terrain

Navigating the terrain

Restricted Vision Problems

Wind Screen Pillar and Internal Roll Cages

It is Important to explain to 4wd drivers that, as you may see from time to time in crash photographs of vehicles with Internal Protection Cages installed or Snorkels that they encroach into the drivers area of vision to the extent that vehicles approaching from the left (left hand drive and similarly the right in right hand drive) at junctions or approaching from the left on left hand bends can not be seen clearly and that a number of accidents appear to be either T boned damage to vehicles or vehicles being T Boned by vehicles. On the approach to junctions and left hand bends (right on RHD) the drivers must therefore be cautious and make an effort to ensure that they are aware of any traffic or obstacles that could be blocked by the windscreen pillar and the internal cage support leg or the Snorkel itself.

Restricted vision issues with 4x4 vehicles

Next Article: Hazard ID, Safety and Environment

Check out other work by Paul, fiction thriller novels here.


This content was prepared for the Off-Road Discovery Website by Xplorability 4wd Training

The Content - All Photographs and Photographic Copyright and All other Rights other Reserved October 2017. S.W. France This content may not be copied or reproduced without the written consent of Paul Sinkinson – Xplorability Training.

For Use Only in 4wd and Light Vehicle Driver Training.

Not for Re-Publication, Distribution or use outside the Xplorability Training Programme