calculating trailer height at angled approach

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Is there a formula for this? I need to know how much to allow for the angle in order to clear the opening.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:Not without more info.... like how long is the approach and does it change angle? and also tow vehicle length behind axle and axle spread...For the main opening you have marked it doesn't matter as you show the ramp extending to it.... now once inside the opening that is a different story

but I see you have an increase in height right after the opening but no numbers...
Reply:The approach is consistent at 4.1% and is 34 feet then levels off. The trailer is 26 feet ball to bumper, tandem axles centered in the middle. The tow vehicle is 21 feet long with 56-58" from axle to ball. Once inside the opening, the floor has a slope of about 1/2" in 26 feet.  The height increases to 12 feet once inside but slopes back to 11 feet at 26 feet in. A trailer dolly could be used if the TV is too long.Last edited by bigb; 10-14-2018 at 06:02 PM.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:I can write up a bunch of math for this, but it'll be much easier for you if you just draw it all to scale with a ruler.The tongue height will affect your calculations as well - center of the axles is the pivot point for the effect. 10'6" plus the distance to the ground is already more than 11' isn't it?Last edited by MinnesotaDave; 10-14-2018 at 07:02 PM.Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:You ever notice the small vehicle with flashing lights and a pole in front of an oversize load?That vehicle is the Mark 3 bridge height to load height calculator.You can sufficiently simulate that system to calculate the opening needed with a stick
Reply:Where is your AC unit? Typically the AC is the highest point on the trailer. It is never at rear, seldom at front. The approach angle, if consistent is only going to influence height An inch. My trailer has the AC a bit behind the rear axle. By the time I should think of AC, the wheels have dropped an inch or more. What about your next trailer? I bought a tall trailer, hated it, and bought a taller trailer next year. Now Mrs. is pressuring me to replace. ALL available trailers are taller than the one we have! I can squeeze under a 10'0'' drip edge now. I have an inch to spare. I can't find a trailer that fits. Go big. Taller is more versatile. 13' 6" is legal limit nationwide. Plenty of fifth wheel units are close to that.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:What am I missing? Per your drawing the trailer is 10’6” inside plus the tires have to be 18”, so you are at 12’ on the level. So it won’t fit an 11’ opening going straight on level ground. Now I suspect you mean 10’6” from top on trailer on level ground. In that case couldn’t you simply measure from top of trailer to ground on the slope or back up slowly?Assuming half the 26’ to axles is 13’ with 2” rise in 4’, 13/4= 3.25x2”= 6.5” additional height. Total 10’6”+6.5”= 11’1/2”. Maybe you could let some air out of the tires and get in.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:I'd grab a spotter and guess and check. then adjust the variables you still have control over.My name's not Jim....
Reply:

Originally Posted by wb4rt

What am I missing? Per your drawing the trailer is 10’6” inside plus the tires have to be 18”, so you are at 12’ on the level. .
Reply:The front edge of the top of the trailer will be at its highest when the hitch is directly over the transition from the slope to the level floor.The front edge of the top of the trailer will be at its lowest when it is directly over the transition from the slope to the level floor.If the AC is directly over the axles(or nearly) it will be at its highest as EACH axle goes over the transition from slope to level floor.Soooo, if the top of the trailer is 10'6" on level ground(or on the slope) then it will be something less than that as it goes through thetransition from slope to level floor.And sooooo, if the ac measure xx'xx" on level ground it will be no more than that as it goes through the transition from slope to level floor.Autism is awesome!!!


Reply:The diagonal line at whatever angle (grade) is what you need to know. Think right triangle.

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"The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Here is a more accurate drawing but still not so great as my drawing sucks. So Rex you are referring to the front of the trailer, or the back which enters first? I guess my concern will be the AC unit. With 6" to spare my gut feeling is it will be OK but if we go to the taller trailer it will be a foot longer and exactly 11' at the AC but a low profile AC could reduce that to about 11'7". None of the dimensions include a roof rack, not sure if I want one.Last edited by bigb; 10-14-2018 at 10:27 PM.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:I think I can replicate something on top of the van using firring strips and cardboard. If I make the back of the van 10'6" and it clears the opening it seems that I should have no problem, because even though the AC unit is further toward the front on a trailer, it should never go higher than it would if it were on the very back right? In essence I will be creating Sandy's example with the red line.Here's a thought, if the grade is 2" in 48" won't that mean in 24 feet the front will be 1 foot lower that the back and won't that mean the back will be 1 foot higher than if it were level? Assuming that the pivot point is in the center.Last edited by bigb; 10-14-2018 at 10:39 PM.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:For practical purposes, the height of your trailer is not at this time vertical, it is off vertical perpendicular to your ramp. Ramp angle is: 100/48"=2.08333 so 2.0833333......X 2" rise is 4.16666666....% grade. In 100" you would drop 4.16666...". Perpendicular to that is the dimension of the door opening in aspect to the trailer. Imagine a triangle with its most acute angle at the top of the door opening. One side of the triangle is vertical. The other side of the triangle is 4.06666...% out of vertical, but stops short of the floor at a point where it meets the 4.1666...% angle projected from the ramp. Your door is 11' or 11 x 12" in a foot, or 132". 132/100= 1.32. The deviation from vertical of the rear side of our triangle is 4.1666...%. So, 4.1666... x 1.32=5.49912 This is very nearly the length of your remaining side. Let's agree that the lower rear corner of our imaginary triangle is 90 degrees  Then A square X B square = C square We know that C square is 132 x 132" or 17424. And B square is 5.49912 x 5.49912 or 30.2403207744 So 17424-30.2403207744 = 17393.7596793 The square root of 17393.7596793 is 131.885403586977" The hole your trailer passes through is a fraction of an inch smaller than your door is tall. As the wheels continue to rise, however, the back of the trailer will rise at that grade, until they drop onto level floor. I presume the ceiling height at the rear of the building is sufficient that the truck will be still on the ramp when the trailer is all the way inside. As the truck hitch rises in height at the rate of 4.1666...inches per 100", correspondingly, the rear of the trailer will fall lower as the hitch rises, and it pivots somewhere in the middle of the axles.Last edited by Willie B; 10-15-2018 at 03:03 AM.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Is there no overhead door to consider?An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:

Originally Posted by Willie B

Is there no overhead door to consider?
Reply:Does the drawing take into account for the vehicle pulling it? If both are not on the same plane, then the towing vehicle will have an effect on the height depending on where the ball falls. It's not much, but in this case could mean a lot.Sent from my 2PS64 using Tapatalk
Reply:If the seller is close just ask to take home for a test run. If it means making a sale I'm sure they will.
Reply:"So Rex you are referring to the front of the trailer, or the back which enters first?"Dang it! Never mind!


Reply:What he said.

Originally Posted by BD1

If the seller is close just ask to take home for a test run. If it means making a sale I'm sure they will.
Reply:

Originally Posted by Boostinjdm

I think that was handled in his other thread.  Exterior mounted roll up if I remember right.
Reply:I was a little surprised I got such a small change in height, but it is a pretty small angle.Drawings are completely out of scale, but you get the idea.


Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:So only .10" height increase?Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:Yeah, it's weird but with only a 2.39° angle, it can't change much.Sin(87.61°) = 0.9991So almost dividing by 1Dave J.Beware of false knowledge; it is more dangerous than ignorance. ~George Bernard Shaw~ Syncro 350Invertec v250-sThermal Arc 161 and 300MM210DialarcTried being normal once, didn't take....I think it was a Tuesday.
Reply:Doesn't seem right somehow. I'd go for 1/10th of a foot, couple of inches +/- ??No math, just WAG and closing my eyes and looking at the mental pic .

Last edited by Sandy; 10-16-2018 at 12:01 AM."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt

Originally Posted by Sandy

Doesn't seem right somehow. I'd go for 1/10th of a foot, couple of inches +/- ??No math, just WAG and closing my eyes and looking at the mental pic .


Reply:Is the ramp in the same plane for the length of truck, and trailer? Truck being on a level plane lower than the inclined ramp would lower the hitch, raise the rear of the trailer. Do you own a bucket loader, or forklift? I used to use a bucket on a tractor to squeeze a motor boat into a barn with an inch of clearance. It worked very well, I could see everything. With a hitch clamped to your bucket you could raise the tongue to improve the height until the AC unit clears.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:This all seems like a lot of pole vaulting over a mouse turd.  For crying out loud, just lay out the angle on the side of the trailer and put a tape measure on it.LanceMultimatic 255 w/MDX-250 EZ-Select gunHypertherm Powermax45 XPHeck Bevel Mill 4000Miller/Smith heavy duty torch set9" Evolution circular saw
Reply:

Originally Posted by LanceR

This all seems like a lot of pole vaulting over a mouse turd.  For crying out loud, just lay out the angle on the side of the trailer and put a tape measure on it.
Reply:Good morning, DaveThat is true about being able to check other angles.  As I have an autocad program it could be done that way in a few minutes too.  As a longtime mechanized infantryman I did my share of route recon work and dealt with percentage of slope, approach and departure angles, overhead clearances at slope etc but that was a loooong time ago.  When we built our last Morton building at our farm I had the front door made 14' tall and 24' wide.  If it was road legal it was fitting in there and we didn't have to drop grain heads on a big combine.....As another thought, if the slope isn't paved it is worth considering tapering it up a bit and having a flat apron at least as long at the distance from the rear of the trailer to the front of the front tire footprint.  that way the trailer would be level backing in......LanceMultimatic 255 w/MDX-250 EZ-Select gunHypertherm Powermax45 XPHeck Bevel Mill 4000Miller/Smith heavy duty torch set9" Evolution circular saw
Reply:

Originally Posted by LanceR

Good morning, DaveThat is true about being able to check other angles.  As I have an autocad program it could be done that way in a few minutes too.  As a longtime mechanized infantryman I did my share of route recon work and dealt with percentage of slope, approach and departure angles, overhead clearances at slope etc but that was a loooong time ago.  When we built our last Morton building at our farm I had the front door made 14' tall and 24' wide.  If it was road legal it was fitting in there and we didn't have to drop grain heads on a big combine.....As another thought, if the slope isn't paved it is worth considering tapering it up a bit and having a flat apron at least as long at the distance from the rear of the trailer to the front of the front tire footprint.  that way the trailer would be level backing in......
Reply:A level apron raises the trailer so it'd sit above where it does now. The truck would still be lower, so coupler is lower, rear of trailer is higher. My little camper with truck are combined at about 44 feet long. If Big has 44 feet of level, we can stop discussing this.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Truck is 21 feet with a turning radius of about 40 acres, trailers we are considering are in the 26 to 28 foot range ball to bumper. Approach is paved then driveway apron, about 38 feet to the street all about the same slope then the street which is basically flat. No tractor or fork lift here, I'm packed into my quarter acre city lot pretty tight. Will probably pick up an electric trailer dolly as it's quite a trick backing in on a blind curve with a traffic circle right in front of me, and the gates are at an angle to the street.Miller Challenger 172Miller Thunderbolt AC/DC 225/150Miller Maxstar 150 STLVictor 100CVictor JourneymanOxweld OAHarris O/ASmith O/A little torchNo, that's not my car.
Reply:

Originally Posted by bigb

Truck is 21 feet with a turning radius of about 40 acres, trailers we are considering are in the 26 to 28 foot range ball to bumper. Approach is paved then driveway apron, about 38 feet to the street all about the same slope then the street which is basically flat. No tractor or fork lift here, I'm packed into my quarter acre city lot pretty tight. Will probably pick up an electric trailer dolly as it's quite a trick backing in on a blind curve with a traffic circle right in front of me, and the gates are at an angle to the street.
Reply:I'd spend time crawling before buying. Long trailers with light frames oscillate. Think of the Tacoma Narrows Bridge. A wave pattern starts, and grows in light framed trailers. 20 footers don't suffer much, 28 footers won't if frame is adequate. Tow that trailer before buying.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:

Originally Posted by Willie B

I'd spend time crawling before buying. Long trailers with light frames oscillate. Think of the Tacoma Narrows Bridge. A wave pattern starts, and grows in light framed trailers. 20 footers don't suffer much, 28 footers won't if frame is adequate. Tow that trailer before buying.
Reply:

Originally Posted by Willie B

Your world is foreign to me. I live on a street with 50 houses. There is one other street in a 38 square mile town with half as many houses. We have 3.2 miles of town road, four miles of state road, and 19 miles of road owned by the feds that lead nowhere. Our population is a bit over 200. Except for the Rainbow family of light gathering in 2016, encountering more than two people in a day is rare. Summer of 2016 residents were terrified!
Reply:My friend who had lived in a number of places including New Jersey, was riding with me one day. I drove around the outskirts of Rutland VT. He looked at me, and said " You've just driven five miles to avoid a little traffic! You don't even know what traffic is! Try leaving home, 1/2 mile from home you think of another tool you need. It takes 40 minutes to get back through traffic to get it!"An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Have you seen the hitch on a house trailer mover. The hitch has about a two foot adjustment hydraulic cylinder to handle this type of problem and grade crossing over railroad tracks. Something like that would make it work a lot easier for you on any trailer you put in there. It does require someone looking and doing it slowly to get it right.
Reply:Dave is correct, getting under the door will not be an issue.  The door is only a problem if the driveway doesn't actually start it's slope right at the front of the garage.  If it is more level for the first couple feet of driveway, then the door could become the problem.If the driveway slope is as drawn then if you have a problem it will be inside the garage.If it is 13 feet from the rear trailer axle to the rear of the trailer then when the rear wheel goes through the door the back of the trailer will be about 7 inches higher than when it levels out.
Reply:but some more accurate info would be handy.what type of suspension does the trailer have, equalizing or non-equalizing?whats the distance from the center between the axles and the rear of the van and distance between back wheel (where it touches the ground) and the rear of the van?the highest point is going to be when the back wheel of the van reaches the crest of the hill (or the center bewteen the axle depending on suspension).half the van length is say 156". 2" rise per 48" over 156" distance is 6.5" increase in height.10'6" + 6.5" = 11'0.5".so without accounting on angle its 0.5" to big.however thats not accurate because its not 11' inside the garage. still need to factor in the actual height of the garage at ~156" inside.as you can see you need a very accurate measurement of how long the van is from the wheels.
Reply:Just borrow the cat's laser toy and tape it on top of the trailer.