Tie down / mounting thoughts

[Chorky]

Since this seems the best location for this question...

In terms of general camper tie downs - they always seem to be outside the camper, going to usually the frame/bumper, possibly a truck bed, or maybe pocket die downs. Either way they always seem to connect to the outside corners of a camper. I'm no engineer but that seems to put a ton of unnecessary stress on a camper's frame. IF one had access to the inside of a truck bed (as if not using a full sized massive beast of a camper, but somethign like an Alaskan, or 4wh), wouldn't it be a better idea to tie down to the inside of the bed of a truck and the inside pocket corner of a camper? Assuming one had some sort of access hatch as otherwise you wouldn't be able to reach the turnbuckels. Even if spring loaded tie downs, this seems like it would put a lot less stress on bed/frame and camper especially for twisty frames.


Something like this (only not ratchets) which I think this is a Scout camper. Seems like it's a better method, again if you are able to reach into the bed. But maybe I am wrong in these assumptions?

 

[jwiereng]

Check out SpaceKap. I think they use some kind of internal tie downs.

 

[simple]

Are you thinking of stress caused by tie downs in a static or dynamic or both condition?

 

[Chorky]

mostly dynamic. However even in static the stress could over time cause damage - if over tightened. I think this concern is more relevant for older flexy trucks than the newer ones with super stiff frames.

 

[simple]

Sounds like you are thinking that as the truck flexes, the relative motion of the frame and camper mounting points would be minimized by moving them inboard. Makes sense.

 

[simple]

I think they are pushed out as far as possible to control a tall heavy awkward box that is quite a bit wider than the surface it is sitting on.

 

[calicamper]

Generally you want camper ties down low close to the floor structure. Those in the picture are pulling on structure with lousy support and are way too high up etc.

 

[Chorky]

camper ties down low close to the floor structure. Those in the picture are pulling on structure with lou

It possibly depends on how the camper is built though. just about all factory built campers have tiedowns on the outside edge of the lip. which just seems like a bad idea to me. the one pictured above is at least on the inside instead the outside. But...maybe my theories the above picture should have less stress placed on the structure than, say a standard outside tie down. However, simple makes a good point as well. I suppose. But I think that for flexy framed trucks, angles probably matter more, and for stiff framed trucks, outside placement would be more beneficial.

 

[calicamper]

It possibly depends on how the camper is built though. just about all factory built campers have tiedowns on the outside edge of the lip. which just seems like a bad idea to me. the one pictured above is at least on the inside instead the outside. But...maybe my theories the above picture should have less stress placed on the structure than, say a standard outside tie down. However, simple makes a good point as well. I suppose. But I think that for flexy framed trucks, angles probably matter more, and for stiff framed trucks, outside placement would be more beneficial.

Wall corner ties on or at lift points make sense but thats not remotely close to whats pictured there. Most campers have very little structure beyond some plywood once you move inboard from the corners and in this case especially on the over hanging part of the camper. I have yet to see any slide in that hangs over the bed sides that has good structural support in the bottom of the bed overhang.

 

[Chorky]

Wall corner ties on or at lift points make sense but thats not remotely close to whats pictured there. Most campers have very little structure beyond some plywood once you move inboard from the corners and in this case especially on the over hanging part of the camper. I have yet to see any slide in that hangs over the bed sides that has good structural support in the bottom of the bed overhang.

I think maybe theres some miscommunication going on? what is pictured is not to suggest what you quoted me... here is a photo of typical camper style tie downs


this seems to place significant stress on the camper structure, which as you mentioned is pretty minimal below this point (the part that sits in the bed of the truck). The style that scout camper is using, pictured in my original post, seems like it would induce significantly less stress to a camper's structure (as compared to a 'typical' tie down style) because of the locations and angles. Angles can cause greater movement the further away from the fulcrum the attachment point is - which would equal more stress. Which makes me think that a tie down that is mounted on the sides of the camper, in theory, would cause even less structural strain. However, you do bring up a good point which I had already thought of. That the lower portions of campers are only made of flimsy plywood and don't offer much structure. This in itself also brings to question though the structural stability of campers bolted through their floors onto flatbed's as then the entire camper is essentially relying on the strength of that base plywood, which seems to be even a worse mounting option simply due to the weight needed to be held by just a few bolts.

I'm no engineer, but it seems that mounting a tie down in this location (big red hand drawn pocket), or a tie down in the 'pocket' (big blue dot) would be about as optimum as possible providing decent strength to the structure (with a backing plate of course), as well as inducing the least amount of stress from a flexy truck frame, so long as the chains/strap goes directly down and ties into the bed - keeping in mind that some sort of access hatch from in the camper would be necessary as obviously you wouldn't be able to reach into the bed with the camper in there.

 

[calicamper]

I think maybe theres some miscommunication going on? what is pictured is not to suggest what you quoted me... here is a photo of typical camper style tie downs
View attachment 682130

this seems to place significant stress on the camper structure, which as you mentioned is pretty minimal below this point (the part that sits in the bed of the truck). The style that scout camper is using, pictured in my original post, seems like it would induce significantly less stress to a camper's structure (as compared to a 'typical' tie down style) because of the locations and angles. Angles can cause greater movement the further away from the fulcrum the attachment point is - which would equal more stress. Which makes me think that a tie down that is mounted on the sides of the camper, in theory, would cause even less structural strain. However, you do bring up a good point which I had already thought of. That the lower portions of campers are only made of flimsy plywood and don't offer much structure. This in itself also brings to question though the structural stability of campers bolted through their floors onto flatbed's as then the entire camper is essentially relying on the strength of that base plywood, which seems to be even a worse mounting option simply due to the weight needed to be held by just a few bolts.

I'm no engineer, but it seems that mounting a tie down in this location (big red hand drawn pocket), or a tie down in the 'pocket' (big blue dot) would be about as optimum as possible providing decent strength to the structure (with a backing plate of course), as well as inducing the least amount of stress from a flexy truck frame, so long as the chains/strap goes directly down and ties into the bed - keeping in mind that some sort of access hatch from in the camper would be necessary as obviously you wouldn't be able to reach into the bed with the camper in there.

View attachment 682155

Funny enough that Alaskan is the exact camper my dad had. The tie downs were on the corners in steel corner plates with a zillion bolts into end wall and side wall and lower wing plate. All campers are usually built this way especially with modern corner jack points. FWC and a few others built better than most put the turn buckles low into the base ie strongest part of the camper and shortest length to limit stretch, shifting, etc.

Bolting into the over hang plate not a tie onto 3 corners is like putting a coat hook on drywall and not a stud.

 

[Chorky]

mper my dad had. The tie downs were on the corners in steel corner plates with a zillion bolts into end wall and side wall and lower wing plate. All campers are usually built this way especially with modern corner jack points. FWC and a few others built better than most put the turn buckles low into the base ie strongest part of the camper and shortest le

hahah that's funny. it's just a totally random google photo. The one comment i would say is in the case of the first post, i'm pretty sure the mounting locations that Scout uses are just fine as they are structural panels I believe, or at least have a backing of some sort. of course doing that without proper support would not be a good idea... However, even if such an area did have good support, it still seems to me that placing tie downs on the red or blue areas of my poor drawing would be much better than the outside corners, even if the outside corners have all sorts of brackets... it would be cool to run a cad program and do some stress testing...

 

[calicamper]

hahah that's funny. it's just a totally random google photo. The one comment i would say is in the case of the first post, i'm pretty sure the mounting locations that Scout uses are just fine as they are structural panels I believe, or at least have a backing of some sort. of course doing that without proper support would not be a good idea... However, even if such an area did have good support, it still seems to me that placing tie downs on the red or blue areas of my poor drawing would be much better than the outside corners, even if the outside corners have all sorts of brackets... it would be cool to run a cad program and do some stress testing...

One thing for sure long tie downs are no bueno. The shorter the better.