Why does a bronco have better breakover?

Howdy,
Just back from the bronco off-rodeo with a buddy who bought a 2023 with Sasquatch package (35in tires). I have a 22 4runner with a 2inch lift on 32s. According to my measurements (suvs side by side), the bronco's fuel tank skid is the same height as the rear diff--11.3 inches. Mine is over 12inches. The bronco also has a longer wheelbase. Nevertheless, the bronco has a much better published breakover angle vs the estimated breakover of the runner with a 2" lift. Can anyone explain why?

Thanks!

 

Larger tires most likely.

 

But what does that mean? The center of my runner is still higher off the ground than the bronco, so isn't that all that matters?

 

You are also comparing a 2 inch lifted Runner to a stock Bronco. Both measure stock vehicles so the Runner sits lower in stock form.

 

It doesn't help that it's a little fuzzy to me whether your estimate includes running boards or not.

 

Were you looking at the numbers for the 2-door Bronco?

 

At least the 4Runner don't break TIE RODS like the Bronco's.....

 

No running boards or sliders.
Published info on bronco says the 4-door model has a breakover angle of 26.3 degrees.
4runner has 19.8 degrees stock. AI estimates breakover with 2 inch lift is 20-22 degrees. But I measure the breakover midpoint at 12.5 inches high for both vehicles, and the bronco has a longer wheelbase. Am I missing anything?

 

The AI usage doesn’t make it a fact.

 

Have you tried actually driving over small hills with your buddy with the Bronco to see any real-world differences?

 

I think my skids hit more on the same lines, but hard to tell.

And yes I definitely agree AI doesn't make it true. Just not sure how else to calculate.

 

I’m not good with numbers, but this seems like a simple geometry problem for those that remember that class. Can’t degrees be calculated with the base of the triangle (wheelbase number), and the height of the triangle (height at lowest point)? Although it probably matters where the lowest point falls along the base measurement.

I’m probably embarrasing myself in front of the mathy people so I’ll stop lol

 

I think you’re on it.

 

Hmm, after thinking about it, the wheelbase number can’t be used directly to calculate breakover angle. Because a straight line from the lowest point on the underbody to the center of tire contact patches will go through tire.

You would need to use a smaller number than the wheelbase so you can draw a straight line from the point of the tire that would touch an obstacle to the height of the lowest point. So, I’m with whippersnapper…the tire size makes a big difference in break over since it shortens the distance between the surfaces that touch obstacles first.

 

Oh interesting. Maybe that's what's going on. 35s definitely glide over obstacles better than the 32s, so that's part of it for sure (part of my skids contacting more). But perhaps all being equal, the bigger tires also make the breakover larger...?

 

I don't think you know what breakover angle is.

 

What is it?

 

It's the simple geometry equation.

 

Unless I’m missing something, when wheelbase and lowest point (edit: at center) are the same, tire diameter would be the only thing that makes a difference.

 

Tire diameter means nothing, except it raises the ground clearance.

Where the tires touch the ground, straight line to mid-point between the tires at the frame.

 

That’s what I was getting at too, but then I realized it was more complicated. There may be TWO equations involved. Maybe more!!!. Maybe enough that it would be easier to take a direct measurement using straight edges, and angle finders. I don’t like math and I’m starting to get the cold sweats thinking about it lol

A straight line from where the tire touches the ground (center of contact patch) to the height at the midpoint of vehicle will go through the tire. You have to take into account that the face of the tire does not interact with the terrain at the same spot as the points that mark the wheelbase. That interaction would be significantly inside of the wheelbase measurement. As tire diameter increases, it moves that point further inside the wheelbase numbers very quickly.

 

“AI” or “large language models” as the current AI fad AI’s are known as, is super advanced autocomplete (what word comes next?) and is not good at math. Brilliant for writing stuff that usually sounds like a human but it’s a dead-end technology and not to be trusted.

It’ll be best to either find the math or a website that has a break-over angle calculator.

I meant the stock 4Runner break-over rating may include running boards, not whether yours have it or not.

 

I found a triangle calculator!


I put in the OP estimate of height at center, and half of the wheelbase number. This method would seem to grossly under estimate breakover.

 

No, the distance between the front and rear axle matters too. The shorter the distance between them the better the breakover. It's all about triangles and trigonometry.

 

And this is the point regarding of the tire diameter I was trying to make, in a picture:

 

In context, I think he was saying height was the only variable when comparing vehicles of the same wheelbase (distance between axles)

 

Don’t get me started on “AI”!! Great!!!! You got me started on AI!!! Breath….ok.. I’m fine now.




Tell me, who thinks they would love to eat an artificial apple?!?! nOBodY!! Why?!?! Because it’s FaKE!!!!!



Ok, I’m calming down now….
That’s what AI is…fake intelligence. It looks good until you bite it and end up spitting out styrofoam bits and glitter out of your mouth for a week.

 

The breakover angle isn't measured at the midpoint of the wheelbase. Rather, it's measured at the lowest point. For a 4Runner, that would be the fuel tank.

 

Asked ChatGPT what a ‘16 Sorento’s breakover is - it’s not officially listed but it’s confident it’s “approximately 19.6 degrees”

A calculator using official minimum ground clearance (crossovers being relatively flat underneath) and wheelbase yields 15.2 degrees.

I’m more inclined to believe that number since the both shorter wheelbase and higher minimum ground clearance Bronco Sport is rated at 18.2 degrees officially by Ford in its lowest form as of the 22MY. (20.4 degrees is optional)

 

it's not. It's published as if it were, but it's not. Okay, even with all the variables, it's still pretty simple geometry... just not the two-number geometry we see published, i.e. clearance and wheelbase.

It's just one of those realworld things that a guy with a straight edge and an angle finder will find faster than a Georgia Tech math major and a uh... whatever formulas work here.