Rear Bumper/Spare Tire Mount Thoughts

[Gary Lewis]

...5-lug and 8-lug Ford pattern, so shouldn't that be enough? The bumper is specific to these trucks.

I was only talking about adjusting the mounting height for different spare sizes.

...the torsional rigidity, which is needed...

I don't think it'll be as twisty as you seem to think. Particularly if you make it LIGHTER instead of heavier, and SHORTER instead of longer (across the back of the truck).

...something that pulls the arm down so it cannot bounce.

A simple bullet-shaped pin that stabs into a socket in the bumper face will accomplish that, without much weight, complexity, or wear.

Yes, the whole thing is overbuilt. But that's the way I like to build. ... It'll weigh more than it needs to weigh, but I'm ok with that.

I like building things overstrength, but building them overweight makes them weaker (at the mounting points, where the weight has to attach to the truck); and puts more wear on the truck; and reduces braking/accelerating/steering performance; and costs more for no more benefit. So there are many good reasons to keep it as light as it can be, without losing any strength.

...even if it doesn't look like it.

As long as you keep replying to my posts in this thread, I'll assume you're at least considering the points I'm raising. If you stop replying to me, I'll quit posting in this thread, but I won't be offended.

And, I'm seriously considering a backup camera as an option to this.

They're remarkably cheap & effective. I just put one in the '04 CV I swapped my mother into. It's wired into the big touch-screen radio I put in it.

https://supermotors.net/getfile/1138982/thumbnail/20180824_102127.jpg

https://supermotors.net/getfile/1138891/thumbnail/20180819_140111.jpg

Finding a place for the camera will take some effort, but it'll probably be easier than finding room for the display.

Ok, I think I now understand about the mounting height for different tires. But since this is getting less and less generic I think the limited tire size capability will be adequate.

As for making the swing arm shorter, there are several issues. One is the stop on the left end. It is something like 2" high in order to effectively capture the arm, but the tailgate only clears the bumper by 1", so it has to be on the left end of the bumper beyond the tailgate. And there's the latch - if the arm stops in the middle the latch will be under the spare tire. So I came to the realization that the arm needed to be full width.

And the wall thickness of the swing arm was picked so that when it is fish-mouthed the full wall is there for the whole weld length, thereby making the weld strong. However, I could downsize the A-arm walls. And I'll look into that. But those arms aren't an appreciable portion of the weight, so won't change the overall wight much.

More later as I have to run now......

[Gary Lewis]

Ok, I think I now understand about the mounting height for different tires. But since this is getting less and less generic I think the limited tire size capability will be adequate.

As for making the swing arm shorter, there are several issues. One is the stop on the left end. It is something like 2" high in order to effectively capture the arm, but the tailgate only clears the bumper by 1", so it has to be on the left end of the bumper beyond the tailgate. And there's the latch - if the arm stops in the middle the latch will be under the spare tire. So I came to the realization that the arm needed to be full width.

And the wall thickness of the swing arm was picked so that when it is fish-mouthed the full wall is there for the whole weld length, thereby making the weld strong. However, I could downsize the A-arm walls. And I'll look into that. But those arms aren't an appreciable portion of the weight, so won't change the overall wight much.

More later as I have to run now......

Time for an update and a few pics. (But, I'll admit that the other pics, like in Projects or on the website are not up to date. )

I think I'm done and ready to have Ben start fabricating it. The most recent changes are:

• I've picked a pin-latch (Ruffstuff's R2215), but I'm having second thoughts as it has a handle that looks to be 3" across and if it were to be in the fore/aft position when the swing arm is close it'll hit the tail light. So, I may change to one with a ball handle.

• I'm going to use a Destaco latch to pull the swing arm down to the stop tightly to ensure there are no rattles and it can't come loose. It'll be their stainless model but it'll look like this one.

• The left stop, against which the arm will rest, will be made of UHMW (ultra high molecular weight polyethylene). I'll machine it to fit once the bumper and swing arm are completed, which will let it fit snugly.

• The jack, which I now have courtesy of my son and his family for an early Christmas, fits neatly on top of the tire carrier via studs that come through the holes in the jack's ladder.

Here's an overall view

Here's a view of the jack mounted. It rests against the piece of angle on the right end, and the studs go through the holes and will be held on with wing nuts and washers. Plus, one of the studs will be drilled to accept a small lock to deter those with sticky fingers.

But, I just thought of a change - I think I'll replace the welded piece of angle with a piece of UHMW, and turn it around so the jack rests on it instead of the swing arm. That way there won't be any metal-to-metal contact. Plus, I'll make the spacers for the studs, the things that hold the jack up off the swing arm, out of UHMW and slip them over the studs. Again, no metal-to-metal contact.

This shows the left stop. The left/front hole in the illustration will have a 3/8" socket-head cap screw down against the land shown about 1/2 way down and threaded into the bumper. And then the pin of the latch will come down the same hole, as you'll see in the next drawing. Also, a 3/8" countersink screw will hold the back of it down to the bumper.

And here's the arm resting on the stop and the pin latch holding it in place. The 3/8" SHCS will take the force of the swing arm hitting the stop, and the slippery nature of UHMW will let the arm as well as the pin for the latch slide onto it nicely w/o taking the powder coat off.

[Steve83]

Time for an update and a few pics. (But, I'll admit that the other pics, like in Projects or on the website are not up to date. )

I think I'm done and ready to have Ben start fabricating it. The most recent changes are:

• I've picked a pin-latch (Ruffstuff's R2215), but I'm having second thoughts as it has a handle that looks to be 3" across and if it were to be in the fore/aft position when the swing arm is close it'll hit the tail light. So, I may change to one with a ball handle.

• I'm going to use a Destaco latch to pull the swing arm down to the stop tightly to ensure there are no rattles and it can't come loose. It'll be their stainless model but it'll look like this one.

• The left stop, against which the arm will rest, will be made of UHMW (ultra high molecular weight polyethylene). I'll machine it to fit once the bumper and swing arm are completed, which will let it fit snugly.

• The jack, which I now have courtesy of my son and his family for an early Christmas, fits neatly on top of the tire carrier via studs that come through the holes in the jack's ladder.

Here's an overall view

Here's a view of the jack mounted. It rests against the piece of angle on the right end, and the studs go through the holes and will be held on with wing nuts and washers. Plus, one of the studs will be drilled to accept a small lock to deter those with sticky fingers.

But, I just thought of a change - I think I'll replace the welded piece of angle with a piece of UHMW, and turn it around so the jack rests on it instead of the swing arm. That way there won't be any metal-to-metal contact. Plus, I'll make the spacers for the studs, the things that hold the jack up off the swing arm, out of UHMW and slip them over the studs. Again, no metal-to-metal contact.

This shows the left stop. The left/front hole in the illustration will have a 3/8" socket-head cap screw down against the land shown about 1/2 way down and threaded into the bumper. And then the pin of the latch will come down the same hole, as you'll see in the next drawing. Also, a 3/8" countersink screw will hold the back of it down to the bumper.

And here's the arm resting on the stop and the pin latch holding it in place. The 3/8" SHCS will take the force of the swing arm hitting the stop, and the slippery nature of UHMW will let the arm as well as the pin for the latch slide onto it nicely w/o taking the powder coat off.

The big tube parallel to the bumper does not add strength - only weight. The whole thing would be lighter, cheaper, & stronger if the big tube went from the pivot up to the spare mount. If you don't want to catch/lock the arm at the pivot (which is easier), you could add smaller material going back down to the bumper for a catch somewhere. But there is no advantage to putting it all the way at the far (driver's) end of the bumper. It will look cleaner & have a smaller swing arc (it won't hit as many things, and it'll be easier for you to walk around it) if the latch is hidden behind the spare like the Bronco's. Putting the spare offcenter will give you a better rear view for backing/trailering. Putting it toward the same side as the pivot makes everything stronger, lighter, & easier.

[Gary Lewis]

The big tube parallel to the bumper does not add strength - only weight. The whole thing would be lighter, cheaper, & stronger if the big tube went from the pivot up to the spare mount. If you don't want to catch/lock the arm at the pivot (which is easier), you could add smaller material going back down to the bumper for a catch somewhere. But there is no advantage to putting it all the way at the far (driver's) end of the bumper. It will look cleaner & have a smaller swing arc (it won't hit as many things, and it'll be easier for you to walk around it) if the latch is hidden behind the spare like the Bronco's. Putting the spare offcenter will give you a better rear view for backing/trailering. Putting it toward the same side as the pivot makes everything stronger, lighter, & easier.

Hmmmm, good ideas. I'll have to think about that one......

Since there's no space above the bumper when the tailgate is down, I put the left stop past the tailgate. And that meant that the arm had to go all the way across. But, if the stop were on the right side, ......

However, one manufacturer of spindles for swing arms such as this was emphatic that you must cinch the swing arm down very firmly as they've had spindles and swing arms damaged when they weren't. And the only way I can see to do that is by placing the clamp a ways away from the spindle. But you can only get 2 1/2" left of the spindle before you are into tailgate territory if the clamp is on the right end of the swing arm. And if you place the clamp there the tire would have about 20:1 leverage advantage on it.

However, another option would be to make the swing arm half-length and bring a piece of square tubing straight down to the swing arm, thereby closing the triangle. And, while I can't put the stop on the bumper or it'll hit the tailgate when it opens, I could put the stop on the swing arm. But, it would have to be a piece of plate making a positive stop, and that would give a metal/metal contact which I'm trying to avoid.

I'll think about this a bit more as maybe I'm missing something simple. So you if see it please let me know.

[Nothing Special]

The big tube parallel to the bumper does not add strength - only weight. The whole thing would be lighter, cheaper, & stronger if the big tube went from the pivot up to the spare mount. If you don't want to catch/lock the arm at the pivot (which is easier), you could add smaller material going back down to the bumper for a catch somewhere. But there is no advantage to putting it all the way at the far (driver's) end of the bumper. It will look cleaner & have a smaller swing arc (it won't hit as many things, and it'll be easier for you to walk around it) if the latch is hidden behind the spare like the Bronco's. Putting the spare offcenter will give you a better rear view for backing/trailering. Putting it toward the same side as the pivot makes everything stronger, lighter, & easier.

I somewhat agree with Steve 83, but only somewhat. The big tube going across is necessary, but it doesn't need to be the strongest piece of the whole frame. The main thing it needs to do is provide a straight shot from the pivot to the latch. To see this imagine what would happen if it wasn't there, but otherwise the whole thing was as drawn above. If you were to put any force forward or backward on the latch (which is what it will do), that translates into a twisting moment on the arm going from the pivot up to the tire. (the Bronco tire carrier doesn't need this because it has a pivot at the top of the fender and the latch at the top of the tailgate, so it has a straight shot from the pivot to the latch in the top tube.) The other thing the tube across the bottom does is triangulate the whole thing which adds a lot of strength. But as it isn't carrying most of the weight it doesn't need to be so beefy. I'd probably do with the same tubing as the top angled pieces for the aesthetics. But it could probably be smaller.

And I definitely would not put the latch on the same side as the pivot. As Gary already noted, the leverage just gets nasty. That puts a LOT more force (like 20 times as much) on both the pivot and the latch. It won't hold up well that way at all.

By the way, here's a link to a thread on a home-built carrier a guy built recently for an early Bronco. It has it's strong and weak points, but you might be interested in it.

http://classicbroncos.com/forums/showthread.php?t=291053

[Gary Lewis]

I somewhat agree with Steve 83, but only somewhat. The big tube going across is necessary, but it doesn't need to be the strongest piece of the whole frame. The main thing it needs to do is provide a straight shot from the pivot to the latch. To see this imagine what would happen if it wasn't there, but otherwise the whole thing was as drawn above. If you were to put any force forward or backward on the latch (which is what it will do), that translates into a twisting moment on the arm going from the pivot up to the tire. (the Bronco tire carrier doesn't need this because it has a pivot at the top of the fender and the latch at the top of the tailgate, so it has a straight shot from the pivot to the latch in the top tube.) The other thing the tube across the bottom does is triangulate the whole thing which adds a lot of strength. But as it isn't carrying most of the weight it doesn't need to be so beefy. I'd probably do with the same tubing as the top angled pieces for the aesthetics. But it could probably be smaller.

And I definitely would not put the latch on the same side as the pivot. As Gary already noted, the leverage just gets nasty. That puts a LOT more force (like 20 times as much) on both the pivot and the latch. It won't hold up well that way at all.

By the way, here's a link to a thread on a home-built carrier a guy built recently for an early Bronco. It has it's strong and weak points, but you might be interested in it.

http://classicbroncos.com/forums/showthread.php?t=291053

Several thoughts. But thoughts, not answers or decisions.

• Tomorrow afternoon I plan to measure my trailers to see if the long swing arm will hit anything on them. That may be a real problem if so, and that will mean I'll have to reduce the length of the lower arm. But, the weight of the extra 36" of lower tubing, assuming I stop it right in the middle, is 20 lbs. And the weight of the extra 23" of the smaller tubing is 14 lbs, assuming I bring it down vertically to the lower tube. So we are talking about a total of 34 lbs.

• As for the size and thickness of the bottom tube of the swing arm, the 3 1/2" height was chosen to give the maximum resistance to rotation or twisting and still allow it to be welded easily to the 4" tall pivot. That's because the center of the tire sits 14 3/4" above the centerline of the bottom tube, and under rapid deceleration the tube needs to resist twisting or the tire or the jack could hit the tailgate. My limited remembrance of the structural dynamics class I took is that the rigidity goes up as the square of the height, assuming the width stays constant, and that has just been confirmed by my nephew who is a mechanical engineer. So the 3 1/2" tube is almost exactly twice as resistant to twisting as the 2 1/2" tube. And the thickness of the tube walls, 3/16", has been picked to allow fish-mouthing it to properly fit the diameter of the pivot on the spindle.

• If I stop the lower arm in the center I could put the plastic ramp on the swing arm so it won't be in the way of the tailgate opening. But, there's not room to put the Destaco clamp right in the center due to the receiver being there. So I'd at least have to extend the lower arm a bit to the left of center, or put the clamp to the right of the receiver.

• That carrier on the early Bronco is interesting. I like how he captured the jack in front of the carrier so that it would be secure if the carrier were somehow locked closed - although I don't think he has that ability.

  But I don't particularly like the way he seems to be securing the carrier. First, it appears that he only has one way - the handled bolt on the left end. That bothers me as I want both a belt and braces approach because if that carrier gets loose it is going to cause a lot of damage. Second, what I've read says you need a strong clamp in the vertical direction to prevent the whole assembly from moving as you go down the road - or off the road. And while that bolt will keep it from going very far, I wonder if it will allow the two pieces of metal to move in relation to each other, which will remove the finish as well as cause noise when the rust starts there.

 

[Nothing Special]

....

• As for the size and thickness of the bottom tube of the swing arm, the 3 1/2" height was chosen to give the maximum resistance to rotation or twisting and still allow it to be welded easily to the 4" tall pivot. That's because the center of the tire sits 14 3/4" above the centerline of the bottom tube, and under rapid deceleration the tube needs to resist twisting or the tire or the jack could hit the tailgate. My limited remembrance of the structural dynamics class I took is that the rigidity goes up as the square of the height, assuming the width stays constant, and that has just been confirmed by my nephew who is a mechanical engineer. So the 3 1/2" tube is almost exactly twice as resistant to twisting as the 2 1/2" tube. And the thickness of the tube walls, 3/16", has been picked to allow fish-mouthing it to properly fit the diameter of the pivot on the spindle.

True and important. But only important between the tire and the mounting points (the pivot and the latch). I suppose the beef of the beam will help resist some of the twisting force as the left side arm is resisted by the pivot (on the right). But I think for the most part the left side will be supported by the latch and the right side by the pivot. So yes, you want a tall pivot and a tall latch, and you want the metal that is supported at the pivot and latch to be tall. But I think it's a lot less important between the two side pieces. Although that might not be the case if you go to a center latch and aren't able to make such a beefy latch. In that case you might need all of those twisting forces to go back to the pivot.

....

• That carrier on the early Bronco is interesting. I like how he captured the jack in front of the carrier so that it would be secure if the carrier were somehow locked closed - although I don't think he has that ability.

  But I don't particularly like the way he seems to be securing the carrier. First, it appears that he only has one way - the handled bolt on the left end. That bothers me as I want both a belt and braces approach because if that carrier gets loose it is going to cause a lot of damage. Second, what I've read says you need a strong clamp in the vertical direction to prevent the whole assembly from moving as you go down the road - or off the road. And while that bolt will keep it from going very far, I wonder if it will allow the two pieces of metal to move in relation to each other, which will remove the finish as well as cause noise when the rust starts there.

As I noted, that carrier has strong and weak points. I haven't looked it over all that closely, but I don't think I'd choose to copy it exactly.

One usually mis-used term that this brings to mind is "over-engineered." People use it to mean something that's built way stronger than it needs to be. But that's not over-engineering. It's over-building, frequently to try to make up for the lack of engineering that went into it to begin with. And pivot and latch points are usually the weak links in under-engineered but over-built tire carriers.

 

[Gary Lewis]

....

• As for the size and thickness of the bottom tube of the swing arm, the 3 1/2" height was chosen to give the maximum resistance to rotation or twisting and still allow it to be welded easily to the 4" tall pivot. That's because the center of the tire sits 14 3/4" above the centerline of the bottom tube, and under rapid deceleration the tube needs to resist twisting or the tire or the jack could hit the tailgate. My limited remembrance of the structural dynamics class I took is that the rigidity goes up as the square of the height, assuming the width stays constant, and that has just been confirmed by my nephew who is a mechanical engineer. So the 3 1/2" tube is almost exactly twice as resistant to twisting as the 2 1/2" tube. And the thickness of the tube walls, 3/16", has been picked to allow fish-mouthing it to properly fit the diameter of the pivot on the spindle.

True and important. But only important between the tire and the mounting points (the pivot and the latch). I suppose the beef of the beam will help resist some of the twisting force as the left side arm is resisted by the pivot (on the right). But I think for the most part the left side will be supported by the latch and the right side by the pivot. So yes, you want a tall pivot and a tall latch, and you want the metal that is supported at the pivot and latch to be tall. But I think it's a lot less important between the two side pieces. Although that might not be the case if you go to a center latch and aren't able to make such a beefy latch. In that case you might need all of those twisting forces to go back to the pivot.

....

• That carrier on the early Bronco is interesting. I like how he captured the jack in front of the carrier so that it would be secure if the carrier were somehow locked closed - although I don't think he has that ability.

  But I don't particularly like the way he seems to be securing the carrier. First, it appears that he only has one way - the handled bolt on the left end. That bothers me as I want both a belt and braces approach because if that carrier gets loose it is going to cause a lot of damage. Second, what I've read says you need a strong clamp in the vertical direction to prevent the whole assembly from moving as you go down the road - or off the road. And while that bolt will keep it from going very far, I wonder if it will allow the two pieces of metal to move in relation to each other, which will remove the finish as well as cause noise when the rust starts there.

As I noted, that carrier has strong and weak points. I haven't looked it over all that closely, but I don't think I'd choose to copy it exactly.

One usually mis-used term that this brings to mind is "over-engineered." People use it to mean something that's built way stronger than it needs to be. But that's not over-engineering. It's over-building, frequently to try to make up for the lack of engineering that went into it to begin with. And pivot and latch points are usually the weak links in under-engineered but over-built tire carriers.

Ok, side-stepping the "how big/thick/strong does the swing-arm material need to be" question for the moment so as to deal with the "how far across does the swing arm need to go" question, I measured my two trailers. And, it is intuitively obvious to the casual observer that the full-width swing arm is NOT going to open with either of my trailers attached. And probably not anyone else's trailer either.

But, a half-width swing arm will clear essentially any trailer as the midpoint doesn't quite reach the ball if the ball is 8 1/2" back of the pin in the receiver, which is about where my draw bars would put it. On top of that, the ball is going to be many inches below the swing arm, so there's chance of hitting.

So, the question I need to answer is whether I want to be able to open the tail gate, and by necessity the swing arm, when a trailer is connected. And, I think the answer is "yes", assuming I can redesign the latches, rubbing blocks, etc to my satisfaction.

So, that's my next quest. And then I'll worry about what material to use.

I'll be back!!!! (But, don't let this keep you from commenting, suggesting, or even critiquing.)

[Gary Lewis]

Ok, side-stepping the "how big/thick/strong does the swing-arm material need to be" question for the moment so as to deal with the "how far across does the swing arm need to go" question, I measured my two trailers. And, it is intuitively obvious to the casual observer that the full-width swing arm is NOT going to open with either of my trailers attached. And probably not anyone else's trailer either.

But, a half-width swing arm will clear essentially any trailer as the midpoint doesn't quite reach the ball if the ball is 8 1/2" back of the pin in the receiver, which is about where my draw bars would put it. On top of that, the ball is going to be many inches below the swing arm, so there's chance of hitting.

So, the question I need to answer is whether I want to be able to open the tail gate, and by necessity the swing arm, when a trailer is connected. And, I think the answer is "yes", assuming I can redesign the latches, rubbing blocks, etc to my satisfaction.

So, that's my next quest. And then I'll worry about what material to use.

I'll be back!!!! (But, don't let this keep you from commenting, suggesting, or even critiquing.)

I'm back! And, I think, and hope, that I have "the answer". But, I'll need several "pics" to 'splain it to you. And, the detail isn't all done, but why get the detail right if I'm going to throw it away - again?

First, I have a spring-loaded pin-lock drawn in just ahead of the vertical tube that comes down from the tire carrier to the lower swing arm. It will ride up on a ramp of that UHMW plastic and then drop in a hole in it to secure the arm temporarily, meaning while in camp but not while on the road.

And, I have a T-bolt that will go into a tapped hole in the bumper to secure the swing arm for on the road. It will pull the arm down against the ramp mentioned above, and prevent it from swinging back.

And both of those are shown here - from the left-front with the bed off:

And here's a closer view of that. Note that the T-handle has a spring to retract it so it doesn't hit the bumper when the arm comes home.

And, there's a 2" x 3" x 1/4" plate on the back of the swing arm to ensure it doesn't go too far forward. However, this puts metal on metal, so I need to space the tab rearward 1/4" so I can put 1/4" of the UHMW plastic on the front of it and still have the swing arm stop flush with the bumper.

And, here's a view from above showing that you can reach both the pin-lock and the T-handle. But, the pin-lock has been changed to a model with a ball for a handle instead of the longer handle as if the handle were left in the fore/aft position it would hit the tailgate when the arm was swung home. And the arms of the T-handle are sized at 3 3/4" total as that will just clear the tire, the tailgate, and the vertical support arm as you tighten it.

And, now for the view that had me stumped for a while today. I downloaded the file for Destaco's clamp as I thought I was going to use it. But, I discovered that it is too tall, top-to-bottom, to put the handle on the bottom as it hung below the bumper. And, when I pointed the handle up I realized that it had to be at least 16" left or right of the tire's centerline or a 35" tire would hit it. So, if you put it on the left you have to extend the lower swing arm 18" past the center, and that defeats the purpose. And, if you put it on the right it is now close to the center of the lower arm, and thereby loses its leverage.

Plus, while the better clamps are rated at 2000 lbs, I've also read that many people have had the "U" break on them. And that wouldn't be good, at all, when on a trail or the highway. So, I think the old-fashioned bolt idea sounds better.

I have a lot of details to work out, like the L-bracket for the T-handle, and how to keep the T-handle in that bracket, and the stop tab needs cushioning, and I need to design the ramp and make sure that will work, etc. But, I wanted to get some feedback before I go to that trouble and then someone points out another major flaw. So, please tell me what you think!

[Nothing Special]

I'm back! And, I think, and hope, that I have "the answer". But, I'll need several "pics" to 'splain it to you. And, the detail isn't all done, but why get the detail right if I'm going to throw it away - again?

First, I have a spring-loaded pin-lock drawn in just ahead of the vertical tube that comes down from the tire carrier to the lower swing arm. It will ride up on a ramp of that UHMW plastic and then drop in a hole in it to secure the arm temporarily, meaning while in camp but not while on the road.

And, I have a T-bolt that will go into a tapped hole in the bumper to secure the swing arm for on the road. It will pull the arm down against the ramp mentioned above, and prevent it from swinging back.

And both of those are shown here - from the left-front with the bed off:

And here's a closer view of that. Note that the T-handle has a spring to retract it so it doesn't hit the bumper when the arm comes home.

And, there's a 2" x 3" x 1/4" plate on the back of the swing arm to ensure it doesn't go too far forward. However, this puts metal on metal, so I need to space the tab rearward 1/4" so I can put 1/4" of the UHMW plastic on the front of it and still have the swing arm stop flush with the bumper.

And, here's a view from above showing that you can reach both the pin-lock and the T-handle. But, the pin-lock has been changed to a model with a ball for a handle instead of the longer handle as if the handle were left in the fore/aft position it would hit the tailgate when the arm was swung home. And the arms of the T-handle are sized at 3 3/4" total as that will just clear the tire, the tailgate, and the vertical support arm as you tighten it.

And, now for the view that had me stumped for a while today. I downloaded the file for Destaco's clamp as I thought I was going to use it. But, I discovered that it is too tall, top-to-bottom, to put the handle on the bottom as it hung below the bumper. And, when I pointed the handle up I realized that it had to be at least 16" left or right of the tire's centerline or a 35" tire would hit it. So, if you put it on the left you have to extend the lower swing arm 18" past the center, and that defeats the purpose. And, if you put it on the right it is now close to the center of the lower arm, and thereby loses its leverage.

Plus, while the better clamps are rated at 2000 lbs, I've also read that many people have had the "U" break on them. And that wouldn't be good, at all, when on a trail or the highway. So, I think the old-fashioned bolt idea sounds better.

I have a lot of details to work out, like the L-bracket for the T-handle, and how to keep the T-handle in that bracket, and the stop tab needs cushioning, and I need to design the ramp and make sure that will work, etc. But, I wanted to get some feedback before I go to that trouble and then someone points out another major flaw. So, please tell me what you think!

I see no major flaws. Personally I think having to turn a screw out and then back in again would be more effort than I'd want to do to open the tailgate. I don't see a great way around that with your goals and constraints. And of course it's not me that needs to do it, so take it for what it's worth.

And a thought from someone else's design (maybe that early Bronco I linked before?), I read that someone wanted the spare tire as far to the left as possible. He thought it would be less in the way of visibility if it was right behind the driver. I'm not sure if I completely agree wit hthat, but it makes some sense to me at least. To see behind you the middle is probably most important. And for lane changes you want to be able to see over the right end of the gate, but to the left you're going to look out the side window. Anyway, just a thought. If you chose to do that (and I'm not saying you should), you could mirror it to put the pivot on the driver's side, and move the tire as far over as you could without the tire hitting the bed when it swings open. (Might give you room for the DeStaco clamp on the end again?)