Fix load to cab + box?

[ToddTheCanadian]

I recently got a 2020 Lariat Supercrew, and am outfitting it.
I am looking at getting a roof rack, and either a cap or a rack for the box.

I've been investigating different roof racks and have seen references to instructions that seem to indicate NOT to attach a load to both the box (via rack/cap) AND the roof rack at the same time?

I wasn't sure why, but figured that there was some amount of shifting possible between the cab and the box that might result in tension to the load and therefore challenge the rack mount points?

And then I saw this:
Ford Flexible Rack System (FRS) for 6th Gen Ranger | Ranger6G - 2024+ Ranger & Raptor Forum, News, Owners, Community (6th Gen)

Which clearly shows a load attached to both the roof and the box (via the rack) at the same time on a factory designed rack?

I am hoping to fill in some of the blanks with the thinking here, and see what your thoughts are on this?
I know many people tie loads to both at the same time, but I want to understand the reasoning before I decide to do this myself.

Thanks

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[Danager]

The frame flexes and you don’t want your added rack or the load you are securing to be what is adding rigidity.
The link you posted shows the support in the bed and then some roof rack - but they are not connected. That surfboard is secured by what looks like bungee cords. That allows for some flex.

I think you will find some racks that secure to the bed and hover over top of the cab. That is probably the best way to go.

 

[navyguy7224]

Get a rhino rack with pioneer system. It comes with the backbone cab mount and have one on the cab and one on the topper so they are independent

 

[Big Blue]

I think what everyone is saying is this. You can support a load across both the cap and the cab without issue. What you CANNOT do is rigidly tie the bed/cap to the cab. Whatever racks you use to support the load must allow for the cab and bed to flex.

 

[ToddTheCanadian]

I think what everyone is saying is this. You can support a load across both the cap and the cab without issue. What you CANNOT do is rigidly tie the bed/cap to the cab. Whatever racks you use to support the load must allow for the cab and bed to flex.

Yeah, I get what you are saying, and appreciate that this is anecdotally true, it just seems like the 6th gen rack doesn't consider that - so I was questioning to what degree it was still true?
That article doesn't only show a surfboard with bungees (which would probably allow the surfboard to go flying at hwy speeds btw (bungees suck)).
That article also shows a ladder, and wood - both of which are moreless rigid loads secured to both the box and the cab racks.

 

[Egg69]

That FRS does look pretty awesome and versatile!

 

[Egg69]

Yeah, I get what you are saying, and appreciate that this is anecdotally true, it just seems like the 6th gen rack doesn't consider that - so I was questioning to what degree it was still true?
That article doesn't only show a surfboard with bungees (which would probably allow the surfboard to go flying at hwy speeds btw (bungees suck)).
That article also shows a ladder, and wood - both of which are moreless rigid loads secured to both the box and the cab racks.

I think the rigid part that needs to be avoided is the rack itself. The fact that the cab rack and bed rack are separate provide the necessary flex. Hope that makes sense. lol

 

[Big Blue]

Yeah, I get what you are saying, and appreciate that this is anecdotally true, it just seems like the 6th gen rack doesn't consider that - so I was questioning to what degree it was still true?
That article doesn't only show a surfboard with bungees (which would probably allow the surfboard to go flying at hwy speeds btw (bungees suck)).
That article also shows a ladder, and wood - both of which are moreless rigid loads secured to both the box and the cab racks.

Neither that ladder or that lumber are rigidly secured to the racks. They are secured but there is still some flexure in that attachment. They are not bolted or welded to both racks. You cannot use a ridgid framework such as a platform or basket to tie the bed and the cab together. Both the bed and the cab are mounted to the truck frame with resilient mounts and need to move independently from each other, and in some situations the truck frame itself will flex.

 

[DukeCanBuildit]

I’d bet that load bar on the chase rack and the cross bars on the roof rack flex vertically and I’d also bet each of those tie-downs they show are a rubber compound, adding additional flex.

It’s cool and all but leaves a lot of room for human error to make a mess of things.

 

[ToddTheCanadian]

Neither that ladder or that lumber are rigidly secured to the racks. They are secured but there is still some flexure in that attachment. They are not bolted or welded to both racks. You cannot use a ridgid framework such as a platform or basket to tie the bed and the cab together. Both the bed and the cab are mounted to the truck frame with resilient mounts and need to move independently from each other, and in some situations the truck frame itself will flex.

Agreed, about all of that, I wasn't really questioning whether welding the cab to the box was a bad idea - (it seems clear, that would be a bad idea.)

In the interest of "science", I did a 10 minute test a little while ago, I attached some pencils to the box and some tape to the cab and went for a drive. I fish-tailed around on some gravel roads, did some washboard, hit a good number of potholes, and drove on the shoulder.
The result was that the pencils didn't really draw any designs, they just got pushed back/broken.

This is the setup:

This is what both pencils looked like after driving around for a few min:

This was a very crude test to be sure, but it makes me think that the flex is mostly front to back, and not side to side, and maybe the g6 rack has that added hinged bar at the top, to account for that flex/movement - which is how they overcome the problem and are able to safely secure a longer load?

 

[Big Blue]

Agreed, about all of that, I wasn't really questioning whether welding the cab to the box was a bad idea - (it seems clear, that would be a bad idea.)

In the interest of "science", I did a 10 minute test a little while ago, I attached some pencils to the box and some tape to the cab and went for a drive. I fish-tailed around on some gravel roads, did some washboard, hit a good number of potholes, and drove on the shoulder.
The result was that the pencils didn't really draw any designs, they just got pushed back/broken.

This is the setup:

This is what both pencils looked like after driving around for a few min:

This was a very crude test to be sure, but it makes me think that the flex is mostly front to back, and not side to side, and maybe the g6 rack has that added hinged bar at the top, to account for that flex/movement - which is how they overcome the problem and are able to safely secure a longer load?

Todd, I really think you are reading too much into this. There is no difference in the way the bed/cab interface behaves between the 5G and the 6G. The flexable terminology used with the new rate applies to the fact the rack being adjustable along the bed rails. All the loads shown are supported by and secured to both the bed and the cab. But, there is the ability to flex between the two. Attaching means to rigidly connect the bed and the cab, that you cannot do.

 

[myothercarizahearse]

spit balling here... maybe the crossbars on the cab and the rack also flex a bit

and why not weld the bed to the cab. that would be 1 stout UNIBODY

 

[ToddTheCanadian]

Todd, I really think you are reading too much into this. There is no difference in the way the bed/cab interface behaves between the 5G and the 6G. The flexable terminology used with the new rate applies to the fact the rack being adjustable along the bed rails. All the loads shown are supported by and secured to both the bed and the cab. But, there is the ability to flex between the two. Attaching means to rigidly connect the bed and the cab, that you cannot do.

I appreciate your input but I feel like you don't quite understand my question (which may be my fault for not being clear enough). I understand that the bed/cab interface is unchanged between the 5G and 6G, and I know when they refer to flexible in the description of the 6G rack, they are talking about versatility and not about solving the problem that is the subject of my question.

The summary answer to my question is that I think Ford solved the problem of allowing for bed/cab flex by adding the hinged support bar at the top of the bed-based rack. Originally, I thought that hinged support bar was just for added height, but I now think the addition of the hinges into this arrangement makes it capable of providing enough flex to prevent damage to the load even when that load is firmly tied to both the roof/cab rack, and the top of the bed rack. (This is a clever solution that wasn't obvious to me at first, which is why I asked the question) I couldn't figure out how they accounted for the flex that we agree is unavoidable.

Incidentally, I really don't buy the argument that this rack design depends on using bungee cords, to tie the load down.

In any case - I feel like it's been answered.
Thanks again

 

[got3fords]

Agreed, about all of that, I wasn't really questioning whether welding the cab to the box was a bad idea - (it seems clear, that would be a bad idea.)

In the interest of "science", I did a 10 minute test a little while ago, I attached some pencils to the box and some tape to the cab and went for a drive. I fish-tailed around on some gravel roads, did some washboard, hit a good number of potholes, and drove on the shoulder.
The result was that the pencils didn't really draw any designs, they just got pushed back/broken.

This was a very crude test to be sure, but it makes me think that the flex is mostly front to back, and not side to side, and maybe the g6 rack has that added hinged bar at the top, to account for that flex/movement - which is how they overcome the problem and are able to safely secure a longer load?

I think you would need slight forward pressure on the pencils to maintain contact with the cab to see all the lateral movement. But the forward and aft movement you captured I would be worried about with a properly secured (no bungees) load. It would be much greater two or three feet above where the pencils are to the actual tie down point.

 

[ToddTheCanadian]

I think you would need slight forward pressure on the pencils to maintain contact with the cab to see all the lateral movement. But the forward and aft movement you captured I would be worried about with a properly secured (no bungees) load. It would be much greater two or three feet above where the pencils are to the actual tie down point.

You're absolutely right about the problems with the pencil experiment and with the amplification of the affect 2-3 ft up.

I was going to attach pencils taped to the cab facing downwards to tape mounted on the box to give me visibility into another axis, and it was when I was walking into the house to find more pencils that I realized that I might be getting carried away, lol.

The pencil experiment worked in so far as it pointed me towards the realization that the hinged bar on top of the 6G rack would probably decouple the load from the box enough to solve the problem.
I'm still pretty confident that this is the answer I was looking for.

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