Rollover Angles

Horizontal Rollover Angle (HRA)



The angle labeled as HRA in the picture above is the Horizontal Rollover Angel (HRA). You need to know the HRA of your car, so that when you are driving on a slope like a dune, you can, by eye, estimate the average angle of the dunes' area and draw your path. Most of the cars will survive until 45°. This angle is not written in most of the manuals, thus, you may need to check it with your car agency.

Check this video to see how you may save your car a rollover if you better study your road and know your car's HRA.

Sometime, the car may slide while within the HRA limit, but because of the existence of some obstacles in the slide or because of the speed, the car may rollover as well, as shown in this video.

Vertical Rollover Angle (VRA)



The concept of a VRA angle, as shown in the picture above, is very similar to the concept of HRA. You also need to know the VRA of your car. There are slight differences between both angles:

• The VRA of any car is usually more than the HRA, where the wheels help keep the car moving instead of rolling over.
• HRA can rollover the car left or right, where VRA may rollover the car onwards or backwards.

1. You are driving within the HRA and your car is in a slope where it's right side is higher than the left side. If you are driving quite fast and your right tire goes on an obstacle, this will make the right side jump and suddenly the HRA will increase which may cause a rollover.
2. If you are driving down a steep slope quite fast and you stop the car suddenly, this will cause the sand to gather in front of the front wheels and make an obstacle; or if you come across a big obstacle, this may cause the car to rollover onwards. The car may also jump over the obstacle and at the time the front wheels touch the ground again, the VRA will be greater than the slope where the front wheels are touching the ground but not yet the rear wheels. This may also cause a rollover.

Car Height

The best performing height of your car is what comes from the manufacturer. Modifying your car will add advantages to your card but at the same time will add disadvantages.

Why would you need to lift your car?

• If you always go offroad on rocky roads, you may need to lift your car. You need just to lift it to something that prevents your card from hitting the rocks. This depends on the places you go to.

• If you always go to desert, then lifting your car is not recommended. Lifting the car will decrease the rollover angle and it can simply cause a rollover where it keeps the center of gravity away from the ground.

• If you go both to rocky and sandy places, then it's advisable to keep your car as it is.

• You also need to know that lifting your card will negatively affect the car performance on normal streets and will require more fuel on highways.

• You may need to lift your car to look good or tough.

4x4 Gear

You may see 4x4 levers in different shapes in different car models. These are the terms you need to know for best handling your car's gear.

You need to know the following about your car:

• The maximum, optimum and least pressure you can put in your tires without affecting their performance
• Tire preferred terrain. Ie. 70% onroad - 30% offroad
• The wider tires you put the more power you spend to move the car. This means more fuel and more money :)