Off-Road Angles: Breaking Down the Basics

August 16, 2023August 11, 2023 JM Logan 0 Comments Off Road Essentials, Off-Roading, Suspension, TrailFX

Understanding off-road angles and how they affect your 4×4 adventures.

Why do we do the things we do… to our 4x4s? No, it’s not some abstract philosophical question as to why we use our vehicles to garner attention and feel love, inclusion, and community; it’s a serious and practical question. Sure, some of us never dare to put our rigs in a situation where they might be scratched or compromised, but for many of us, that’s their purpose – the entire reason they exist.

Aside from aesthetics, we purchase off-roaders and aftermarket accessories to serve a purpose. We do the things we do to our 4x4s to increase their capability and prowess. And while capability means different things to different wheelers, there are a few things that can, in fact, be measured and given a number. Many in the automotive space think of horsepower, torque, curb weight, and payload. But for those who spend a considerable amount of time off the beaten path – in the mud, creek beds, and trails, there are a few more important numbers to consider.

You’ve no doubt heard the terms approach angle, departure angle, and/or breakover angle if you’ve spent any time steeped in the theory or practice of off-roading. But what do they mean? How do you calculate them? And what can you do to improve them?

Approach Angle

The most widely mentioned angle of the three is the approach angle. You’ll often hear this term thrown around in marketing for new off-road vehicles, as well as off-road focused trim level packages. But what exactly is it?

The approach angle of a vehicle can be described as the angle between where your front tire touches the ground and where the lowest point of the front of your vehicle sits—which is usually the bumper.

Diagram showing approach angle and ground clearance — Image | *Suzuki*

This angle determines how steep of an obstacle your vehicle can climb without that lowest front part of the rig hitting it. Conversely, when exiting an obstacle, approach angle affects how steep your vehicle can descend before that bumper bottoms out on the ground below.

This makes sense when you think about your tires not being the most forward part of your vehicle—unless you’re piloting ol’ Gravedigger. If you take a side profile of your rig, it’ll most likely be your bumper that is the lowest, most forward thing. So, when you approach an impediment, your bumper will get there first, with your tires following next. Think about that space, angle, and time between when those two reach the obstacle, as when the approach angle is king.

And sure, it’s something nice to know when buying or modifying a vehicle, but most of us aren’t getting out of our car with a protractor and a ruler to measure that rock in front of us. Just know that more is better.

So, what can you do to improve your vehicle’s approach angle in the aftermarket? Here are a few ways.

Shorten Nose Length

Full size bumpers are great for the farm or workplace, but generally stick out from your vehicle much more than stock, making them non-ideal for off roading. The shorter the front end, the greater that angle is between it and your tires.

No one likes to be called ‘stubby’, but in the off-road world, stubby bumpers are the key to approach angle. These are short bumpers that sit high, compact, and have minimal love-handles to allow plenty of clearance for larger tires. Think of the nose of a pug vs. the nose of a borzoi.

Lifted Suspension

Pretty simple to understand this one – raising the vehicle body’s height will obviously raise that frontmost point of your bumper as well. In return, this will increase the approach angle for tackling that rock, hill, or snowbank the plow trucks made in the back of the Target parking lot. A jacked up 4×4 can also leave you ample room for our next upgrade.

Increase Tire Size

Just like with the suspension, larger tires will raise the body off the ground even more, giving you a few extra centimeters or inches, which increases approach angle.

Trash/Relocate Unneeded Accessories

Before I became neck-deep in the 4×4 scene, I got myself a cute little bull/nudge bar for the front of my vehicle. It looked pretty good and gave me some front-end protection, but what I didn’t realize was it cut down my approach angle. Not only did the bull bar become the furthest forward part of my vehicle, but it also made my vehicle longer – a no-no for those seeking more approach angle. I ditched it and went with a tight, low-profile bumper soon after.

Your winch, albeit a vital accessory, can also add length to your vehicle along with things like your hooks and d-rings. Stubby bumpers generally allow top mounting, placing accessories closer to your grille to prevent approach reduction. So, keep this in mind when aftermarket shopping.

Departure Angle

Now that you’ve got the basics of approach angle down, understanding departure angle should be fairly straightforward. And as you might expect, departure angle has an effect on how steep a decline your vehicle can traverse without the rear bumper bottoming out as you get back to flat ground. It also determines how steep an incline you can tackle as well, since your bumper dips down toward the ground as you start your ascent.

Whereas approach angle is measured from the front tire to the lowest part of the front bumper, departure angle is from the rear tire to the lowest part of the rear bumper.

As for what you can do to increase departure angle, it mirrors the same steps as augmenting your approach angle. A shorter, higher bumper, lift kit, and bigger tires will all help with departure angle. The one slight difference is what a winch can be to the front of your vehicle, a tow hook/package can be to the rear.

If you have a hitch or anything else that decreases departure angle and can be removed, go ahead and save that for the camper or jobsite. We love a good towing accessory, just not at the expense of off-road performance.

Diagram showing departure and breakover off-road angles — Image | *Suzuki*

Breakover/Ramp Over Angle

So, we’ve covered the front and rear of your rig, what about the middle? Or alternately put, the undercarriage of your vehicle? Not as talked about as the previous angle, the breakover angle determines what obstacle can be traveled over so that your underside does not scrape the earth below.

To figure out your breakover angle, you’ll need to know your wheelbase and your ground clearance — two things you can easily measure or look up if your vehicle is stock. You then will need to put those into the following formula:

Departure Angle = 2 * atan(2 * Ground Clearance /Wheelbase)

The calculation of this angle is quite a bit more high-school trigonometry than the other two. Perhaps some of you are in high school and it’s right up your alley, but for most of us, the gaskets and oil seals in that part of our brain have long since failed.

That’s why, we recommend just using one of the many online calculators.

And just like we said before for approach and departure, lifts, tires and anything else that gets your vehicle up in the air will add ground clearance and assist in breakover. Plus, like winches and hitches eat up a bit of angle in the front and rear of your vehicle, low hanging pieces on your undercarriage, like exhaust, driveshafts, and covers can impact your breakover angle. Most of the time there’s not much you can do here to improve, but some off-roaders go as far as to relocate and chop unnecessary components.

Recap

So, what did we just learn? To put it in terms probably much too oversimplified, start by picturing a mountain — like one you’d draw in grade school with a pointed jagged snow peak at the top.

A good approach angle will help get both wheels of your car up on the mountain’s incline to start the journey.
A good departure angle will help get both wheels of your car back to level ground when you’re finished.
And a good breakover angle will make sure the middle of your car doesn’t get stuck on top of the mountain.