Ramp strength

[rimshot]

Holy Pete, though...look at that backhoe! You end up with so much of the tractor's weight over the rear tires it isn't funny! As the BH slides rearward, it creates a moment that pulls the entire center of mass from the front of the tractor to the rear...as it slides rearward, the rear tires have a proportionally higher ratio of the load. Though the backhoe weighs only 700# on paper, the net effect by compounding the moment against the rest of the tractor probably adds a lot more than 700# to the rear wheels of the tractor. Of course I'd have to do some calculations...

If it were me, I'd look into some type of "folding" brace. You could make it out of relatively thin material since your strength would come in the width. If you hinge it against the box-sections that are already there, you could have them nest inside the existing ramp and fold down (they would be straight down...perpendicular to the top of the ramp) when you use the ramps. They could be triangular...narrow toward the front of the ramp and a solid 9 or 10" tall at the center of the ramp. But make them out of 3/32 steel...or 3/16" aluminum even. You could brace them against each other in the center once standing.

You can add all the 1-1/2" steel angle you want...you'll still have an awful lot of flex.

That's my thought.

=====================

Actually it is even heavier than that. The CK20 hoe weighs in at 1100 lbs. i believe the use of those center chocks are the easiest fix. With those in place the ramp becomes very sturdy.

rimshot

 

[KeithInSpace]

center chocks are the easiest fix.

Sounds a little simpler, don't it...

 

[Blk88GT]

This is one of the cases where I like the fold up ramps. I hate them for everything else.

 

[Charlesaf3]

WHy do you hate fold up ramps? Buying a trailer and am curious

 

[Skyco]

One drawback to folded ramps that don't easily detach- if you need to haul something long that could hang off the back you have a problem. IOW with a long car or truck the trunk or bed can't hang out the back or the folded up ramps will hit it. They also add unneccesary wind resistance when towing empty...one of my smaller trailers has a full width expanded metal gate that when standing up feels like it might as well be solid, it can fold all the way over into the bed of the trailer though when empty- the difference in perceived feel of wind resistance is substantial.

 

[Diamondpilot]

one of my smaller trailers has a full width expanded metal gate that when standing up feels like it might as well be solid, it can fold all the way over into the bed of the trailer though when empty- the difference in perceived feel of wind resistance is substantial.

I have a degree in aerospace and know a lot about drag. A mesh gate actually has more drag than a solid piece of wood/steel the same dimensions. The reason for this is what is called "parasite drag" In simple terms all the little holes in the mesh give more surface area for parasite drag to create the drag where as a solid piece would only make the drag around the edges once under way.

Chris

 

[Blk88GT]

One drawback to folded ramps that don't easily detach- if you need to haul something long that could hang off the back you have a problem. IOW with a long car or truck the trunk or bed can't hang out the back or the folded up ramps will hit it. They also add unneccesary wind resistance when towing empty...one of my smaller trailers has a full width expanded metal gate that when standing up feels like it might as well be solid, it can fold all the way over into the bed of the trailer though when empty- the difference in perceived feel of wind resistance is substantial.

Couldn't have said it better myself. Also, the ramps are typically shorter when they're the fold down variety than the pull out. This makes loading low vehicles very difficult.

The ramps are also difficult to slide on their mounting shaft once it has been used a bit and the shaft isn't as straight as it once was.

 

[Charlesaf3]

thanks all.

Diamond pilot, that's very interesting. Thanks for sharing that. I love the random stuff I learn here.

Does that mean that attaching a piece of sheet metal to stand up ramps will improve gas mileage?

 

[KeithInSpace]

What Mr. Diamondpilot is suggesting is that the aggregate effect of a whole bunch of little bitty low pressure areas pulling back on the cheese grater ramps while in travel are HIGHER RESISTANCE than the effect of one big fat low pressure area pulling back on, say, a SOLID ramp (no holes...plywood).

I concede the point that the cheese grater ramps have an ENORMOUS amount of wind resistance, I'd need to see data confirming it is, indeed, more aggregate drag. Wouldn't attach the plywood to save gas just yet. But if you did, you probably wouldn't notice much of a difference one way or another...

I further concede that it would be GREAT to be able to fold down the heavy duty ramps shown on Mr. Blk88GT's trailer, but I am certain they produce FAR less drag than the landscape style mesh steel (cheese grater) ramp. I'd be hard pressed to say you could feel the wind resistance from those over the actual weight of the trailer, especially when loaded.

 

[Diamondpilot]

Keith is right. The cheese grate type is the ones that kill you with the drag. My wifes uncle runs a trucking company on the Indiana Illinois state line and they travel once a day to Columbus Ohio. His fleet consist of 20 or so Semi trucks, 5 or so F-150 Long bed 2 wheel drive trucks, and 2 20' tandem axle trailers that are identical except one has a fold up mesh gate.

One Christmas we were all sitting around talking guy stuff and taking each others money playing cards. He was telling us that one of his trailers had a problem and he could not figure it out. He said he had all new running gear put under it including tires but could not figure out why it could only make it to Indianapolis behind one of the companies F-150's when the other trailer could get back to the state line with a few gallons to spare. He told us he even took it to a alignment shop to make sure the trailer was straight. I asked him if it was the trailer fold up gate. He said yes. I told him it was the gate and his response was it has holes in it.

Long story short he took the gate off and it now gets the same results as the other trailer. The mesh gate was making the truck get about 10-15% worse fuel economy at highway speeds hauling the typical 6,000# load.

Chris