.

[tock13]

I’m probably the only one who thinks this, but I still think the design of the studs is poor. They should have been incorporated into the window frame and not attached to a plate. Spot welded or adhesive, it seems weak for the intended purpose.

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[Malicar]

single center (and) hitch mount for a roof rack will permit too much torsion of the rack.

0 rear movement. Hitch milled .005" under receiver. Turn buckles. Billet 6061 AL rnd coped, welded. Would break before bend or twist.

Any movement was in ladder on top. Bolted to coped rear post. 6061 Tube. Blocks have hole .065" over ladder tube, ladder secured by pin in the blocks.

Happened with up/down bounce, no side loads at the time.

Do you doubt a Bronco can wheel hard with a traditional multi-point roof rack and attachment system on a hard top?

With anymore than 150lbs? Yes. Especially after seeing cracking cardboard hardtops and windshield mounting plates spot welded to sheet with 6mm studs.

Only real option I see is exoskeleton rack.

 

[telenerd]

I have a good solution. Less weight, cheaper, better mpg, and can’t even tell it’s on your bronco.

 

[Malicar]

I’m probably the only one who thinks this, but I still think the design of the studs is poor. They should have been incorporated into the window frame and not attached to a plate. Spot welded or adhesive, it seems weak for the intended purpose.

Your not alone.
The window frame is tied in with the roll bars.
You would think if the windshield can take a 5000lb bronco upside down on it, it could take some sturdier rack mounts for more weight rating.

 

[Malicar]

I have a good solution. Less weight, cheaper, better mpg, and can’t even tell it’s on your bronco.

Still weighed less than the ex. I'm ahead now.
Too much luxury in the rooftop to go back.

 

[LMF Bronc]

I guarantee those mounts are intentionally made to fail in that scenario... you make them stronger by tying into the windshield frame/roll bar and you're asking to have major damage. That's a relatively easy fix, and Ford can point to the 100lb dynamic rating to deny warranty coverage. Good luck, but I'll be shocked if it gets covered.

 

[HotdogThud]

Your rack design is the fundamental problem, very unlikely the vehicle. The lack of rear torsional support placed too much load into the front mounting points.

There are plenty of Broncos with racks and RTTs that combined weigh way more than the measly dynamic 100 lb load limit I have heard of. These folks wheel hard with no problems.

Bingo.

I'm a reasonably big dude, and I am 1000% certain I could put my feet up on the tire, grab the front-to-rear bar and yank and pop that thing right off. And that is nowhere near the dynamic load it would see while wheeling.
A better design if one was going to give up the use of the soft top would be to mount horizontal plates to the sill above the rear fenders (there's nutserts there, you know) and tie in a support vertically there instead of putting an extra 6-7 linear feet of tubing all the way down to the hitch.

Also, inb4 the warranty claim denial

 

[Malicar]

Bingo.

I'm a reasonably big dude, and I am 1000% certain I could put my feet up on the tire, grab the front-to-rear bar and yank and pop that thing right off.

You think people didn't try that?

 

[Lcubed]

Your not alone.
The window frame is tied in with the roll bars.
You would think if the windshield can take a 5000lb bronco upside down on it, it could take some sturdier rack mounts for more weight rating.

that's the difference between compressive and tensile loads.

example: concrete is fantastic in axial compressive loads (2 to 5 ksi),
not so good in tensile loads (0.3 to 0.7 ksi)

 

[Malicar]

that's the difference between compressive and tensile loads.

example: concrete is fantastic in axial compressive loads (2 to 5 ksi),
not so good in tensile loads (0.3 to 0.7 ksi)

Steel has nearly identical compressive/tensile load ratings. The only difference would be cage design to take hits instead of pulls.
Also don't need to stick 5000lbs on top, the windshield frame itself could easily take a 500lb dynamic rating.

 

[Lcubed]

Steel has nearly identical compressive/tensile load ratings. The only difference would be cage design to take hits instead of pulls.
Also don't need to stick 5000lbs on top, the windshield frame itself could easily take a 500lb dynamic rating.

true for steel, not so much for epoxy adhesives

 

[cr117]

the windshield frame itself could easily take a 500lb dynamic rating.

You're missing the point. Ford designed these mounts to break away under a certain force to prevent anything on the roll cage/frame from getting bent. Would you rather risk bending part of the roll bar from an overloaded roof rack and likely totaling the vehicle? I guarantee you the engineers at Ford have put way more thought, analysis, and testing than any of us could.

 

[Malicar]

You're missing the point. Ford designed these mounts to break away under a certain force to prevent anything on the roll cage/frame from getting bent. Would you rather risk bending part of the roll bar from an overloaded roof rack and likely totaling the vehicle? I guarantee you the engineers at Ford have put way more thought, analysis, and testing than any of us could.

Its meant to take 5000lbs smashing down on it. Pretty sure the engineers didn't go crazy on the mounting points because they don't want Susan rolling her suv. Not to mention our GVWR is small enough without 500lbs added.

 

[dwbronco]

Installed a 175Lb rooftop tent on top of my diy rack.
Bouncing through a hole, popped the plug welded plate off.
Someone had to find the limits

View attachment 544333

View attachment 544334

View attachment 544335

Were you in your rooftop tent, when you were "bouncing through a hole?"

 

[swamp2]

0 rear movement. Hitch milled .005" under receiver. Turn buckles. Billet 6061 AL rnd coped, welded. Would break before bend or twist.

Any movement was in ladder on top. Bolted to coped rear post. 6061 Tube. Blocks have hole .065" over ladder tube, ladder secured by pin in the blocks.

Happened with up/down bounce, no side loads at the time.

Zero, right that's a wet dream... Do you also think zero tension loads on your mounts? Did you run a single calculation in coming up with this design? Loads, stresses, anything or pure backyard engineering?

OK, wait you're right. You got the one defective vehicle out there, all of the others are perfect and your rack is perfect too. Hmmm, or maybe yeah, Ford did no testing, all Bronco's are defective and no one with a roof rack and a RTT or storage wheels at all...

Ever heard of Occam's razor?

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