Fuel Tank Relocation (and new Rear Bumper design)

[jkeith.w]

What I want to see is a clever swing-out design. I haven't gotten a warm and fuzzy feeling from any of the designs out there. I know most of them 'work' but I still feel there is room for improvement.

-Charlie

While I agree with you, which areas, specifically, do you find underwhelming?

 

[jkeith.w]

OK guys - we're less than a week from starting to ship these out; you can go ahead and pay for your fuel tank mounts here:

jkeithwalters.com/tankmounts

(- or click the link in my signature below.)

I'll calculate shipping for everybody when I have the first set boxed up and weighed, then I'll send out paypal funds requests for the shipping costs and get these things out to you all.

The crossmembers are ready! But if you guys'll bear with me, I'm hoping to pick them up with the 5th gen PCKs (which are due in a couple of days) - it's an hour trip each way for me...

Is everyone ok with that?

 

[Rockdawg84]

OK with me

 

[Rcastle]

I am good with that. I am in no hurry.

 

[phattyduck]

While I agree with you, which areas, specifically, do you find underwhelming?

Most designs I have seen use a single post, mounted only on one end. While you *can* make that work, it really concentrates forces on the base of the pivot point. I have seen at least one that uses a couple heim joints spaced vertically, which could be better but doesn't necessarily look cool.

Even a pivot in double shear like this:

Still puts a large moment forces on the pivot.

Then on the latch side... it should share the load not just in the vertical plate (weight directly down) but also the rotational forces of the tire/fuel/whatever hanging out behind the hinge/latch plane.

The latch on the CBI bumper is getting there:

But the rotational forces are still concentrated on a small area.

Its a bit hard to articulate all these thoughts, hopefully they came across. I know there are major packaging limitations - there just isn't much vertical room below the tail lights to spread/triangulate loads.

As a reference - all OEM tire carriers that I can think of use two hinges, spread apart vertically (reference Hilux Surf tire carrier, but even Jeep tire carriers are that way). Its the only way to reliably hold the load with OEM quality/reliability.

-Charlie

 

[jkeith.w]

(Charlie, I’m coming back to this in a minute!)


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[jkeith.w]

So this happened:

(that’s a pile of crossmembers I just picked up)

Give me a couple of days to package and figure out shipping and then these things will go out to their new homes!


Sent from my iPhone using Tapatalk Pro

 

[jkeith.w]

Most designs I have seen use a single post, mounted only on one end. While you *can* make that work, it really concentrates forces on the base of the pivot point. I have seen at least one that uses a couple heim joints spaced vertically, which could be better but doesn't necessarily look cool.

Even a pivot in double shear like this:

Still puts a large moment forces on the pivot.

Double-shear is really the only way to pull it off, bumper-mounted, on these trucks, IMO - unless you like your bumper having a colossal shelf to sink a post into...

Then on the latch side... it should share the load not just in the vertical plate (weight directly down) but also the rotational forces of the tire/fuel/whatever hanging out behind the hinge/latch plane.

The latch on the CBI bumper is getting there:

But the rotational forces are still concentrated on a small area.

this is a very good point! - probably why every non-factory solution rattles/knocks around after a while - torsional loading, right?

Its a bit hard to articulate all these thoughts, hopefully they came across. I know there are major packaging limitations - there just isn't much vertical room below the tail lights to spread/triangulate loads.

Right - it's a design nightmare - and:

As a reference - all OEM tire carriers that I can think of use two hinges, spread apart vertically (reference Hilux Surf tire carrier, but even Jeep tire carriers are that way). Its the only way to reliably hold the load with OEM quality/reliability.

- the problem with this is that you have 2 huge hinges hanging off the side (because of the hatch/taillight designs) - which are surely in harm's way.

on the other hand, the factory latch is sort of behind the weight and carries the load much better...



I'd already decided to make a mount to hold my spare vertically on the driver's side wall of the rear cargo area (for visibility concerns), but recognize that virtually everyone wants a bumper-mounted swing-out... so I'm thinking about how to pull it off.

Worst case, I guess I could work up a double-shear mount and let folks design their own best solutions for the rest of it?

 

[jkeith.w]

Do you think we could mount the spare to the hatch itself and come up with some appropriate struts to lift the weight? (probably too dangerous when the struts inevitably fail)

 

[Tyler James Inc]

Do you think we could mount the spare to the hatch itself and come up with some appropriate struts to lift the weight? (probably too dangerous when the struts inevitably fail)

That. Sounds. Scary.
That's an interesting thought though. Maybe you need to do a collab with RockyMtnRacks to build an upward swinging tire carrier- hinged off their rack! [emoji23]

 

[clearock]

Double-shear is really the only way to pull it off, bumper-mounted, on these trucks, IMO - unless you like your bumper having a colossal shelf to sink a post into...

not sure about the sink... yet, but my set up does stick out, but my primary use is as an expo vehicle that i live out of for months at a time and 4x4ing secondary. The ability to lock out the swing has been high useful and adds safety when using on uneven ground. I support a large amount of weight and so far everything is holding up with out issue. If I build another one that's primary use is for off road I was thinking i could weld the hub upside down (weld the housing to the bumper) and use the spindle part as the mount point for the swing out and still have the ability to lock out. Hope this helps with ideas for a better design.

 

[jkeith.w]

View attachment 306953

holy moly you carry a lot of weight on that hub! what's going on with the tubing on the sides of the truck?

 

[rkntoy]

not sure about the sink... yet, but my set up does stick out, but my primary use is as an expo vehicle that i live out of for months at a time and 4x4ing secondary. The ability to lock out the swing has been high useful and adds safety when using on uneven ground. I support a large amount of weight and so far everything is holding up with out issue. If I build another one that's primary use is for off road I was thinking i could weld the hub upside down (weld the housing to the bumper) and use the spindle part as the mount point for the swing out and still have the ability to lock out. Hope this helps with ideas for a better design.

I like the setups that use the hub, but over time I have seen quite a few of these snap since there is not an easy way to make them double shear.

I hope you don't get rear ended - would be worse than a Ford Pinto.

 

[Scramble]

Can you upgrade the fuel pump in the Ford tank easily? I'm S/C'ing eventually & need a high LPH Walbro. I plan on going flat belly.

Thanks for all of the research on this.

 

[clearock]

I like the setups that use the hub, but over time I have seen quite a few of these snap since there is not an easy way to make them double shear.

Sense building the swing I am careful to inspect for issues. I bolt the unit into place when its closed to help transfer some of the load while driving. IMO before the unit where to shear the weld at cast hub would the 1st fail point, would have been better to sleeve the hub first.

I hope you don't get rear ended - would be worse than a Ford Pinto.

I assume u r talking about my rear tank fill point? If so my bumper provides as much if not more protection then the oem tank placement, my rear bumper is heavily over built with the Pinto and swing out in mind (not to say the best of intention doesn't go awry) . With the space limitations and trying to maintain a low CG my battery bank is placed as best as I could come up with...

I was just in Bend and at Smith Rock, its a really nice place.

 

[clearock]

holy moly you carry a lot of weight on that hub! what's going on with the tubing on the sides of the truck?

It's partial exo because I wanted a full rack and to provide some protection because i tend to go where I shouldn't... As I make my rig more 4x4 capable I can add to it if I want.

 

[Coward]

I'd like a diagram of what all you got going on in that picture! I see the spare, and the air compressor. I understand your extra fuel tank fill point in your bumper. What are the other things on the bottom? Water tanks or batteries?

 

[jkeith.w]

It's partial exo because I wanted a full rack and to provide some protection because i tend to go where I shouldn't... As I make my rig more 4x4 capable I can add to it if I want.

Let’s see it!


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[clearock]

I'd like a diagram of what all you got going on in that picture! I see the spare, and the air compressor. I understand your extra fuel tank fill point in your bumper. What are the other things on the bottom? Water tanks or batteries?

Battery bank

 

[clearock]

Let’s see it!