breakover angle (got bored)
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breakover angle (got bored)
Well,I got really bored today, so I decided to go outside with a tape measure, do a bit of math, and figure out breakover angles. Checked the Ford lit. and it isn't even close to what i got. My question is, how do 'they' measure ramp breakover angle, and a lower one is better right? Like 13* opposed to 20*? Thanks
Laughing Gas
Joined: Mar 2003
Posts: 943
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From: Randolph, NJ
How did you measure? I assume Ford reported the excluded breakover angle at 20*. A higher excluded breakover angle would mean that you could go over a steeper ramp obstacle without scraping bottom. (A higher included breakover angle would mean the opposite.)
http://skidplate4x4.tripod.com/The_B...xplanation.htm
Based on the diagram, I would think that the included breakover angle would be:
2*arctan (1/2 *wheelbase / height)
Then I'd think the excluded would be:
1/2 * (180- included breakover angle)
From the diagram, I'm unsure if you are supposed to measure from wheel center to center or from where the tire hits the road on front and back. That could affect your results a few degrees.
Interesting question. Good use of your time when you're bored.
-Jim
http://skidplate4x4.tripod.com/The_B...xplanation.htm
Based on the diagram, I would think that the included breakover angle would be:
2*arctan (1/2 *wheelbase / height)
Then I'd think the excluded would be:
1/2 * (180- included breakover angle)
From the diagram, I'm unsure if you are supposed to measure from wheel center to center or from where the tire hits the road on front and back. That could affect your results a few degrees.
Interesting question. Good use of your time when you're bored.
-Jim
Last edited by PSKSAM2; Apr 7, 2006 at 10:10 AM.
Senior User
Joined: May 2005
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Normally, breakover (and approach and departure) angle are measure form tire contact to the ramp... easiest way to physically measure is to use boards, which for breakover requires trimming to get the right lengths. So generally, it becomes a calculation - centerpoint of the wheelbase to the hypothetical first point of contact. you'll have to approximate the first point of contact to determine the end of the imaginary lines. Then it's back to high school geometry - Pythagorean theorum - a squared plus b squared equals c squared. you can calculate the angles from there as well.
All this ends up being predicated on tire size and spring sag, etc. No two trucks will be exact, but you would expect to find them within a degree or so.
All this ends up being predicated on tire size and spring sag, etc. No two trucks will be exact, but you would expect to find them within a degree or so.
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Yeah I did a few ratios and such, and applied a few laws, but then i realized I had been assuming the angles were measured from the tire's contact patch center. Also, I didn't get as precise as I could/should have. Oh well. I was entertained for a bit...
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