Tailgate reinforcement needed?

[NINTH]

Getting conflicting reports that the stock JL tailgate hinges can either support a total of 85lbs OR an additional 85lbs + the stock spare?

Can someone clarify for me?

Have a JL Sport and just upgraded wheels/tires to Method 703 17x8.5 with Falken Wildpeak AT3 285/70/17 so the new weight of the wheel and tire combined is about 95lbs.

Do I need to reinforce the tailgate or can the stock hinges support this increase in weight?

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[The Last Cowboy]

No. That combo weighs no more than a stock Rubicon/Willys wheel and tire.

 

[NINTH]

No. That combo weighs no more than a stock Rubicon/Willys wheel and tire.

I thought the stock wheel/tire set up is like 70 lbs? I guess a 20 lb jump isn't crazy tho

 

[The Last Cowboy]

I thought the stock wheel/tire set up is like 70 lbs? I guess a 20 lb jump isn't crazy tho

A 33' Rubicon/WIllys tire and wheel is ~80 lbs, and has no reinforcement. An XR 35" wheel and tire is heavier yet (~86 lbs), and will come with the Mopar reinforcement., which stiffens the tailgate, but does nothing for the hinges.

My Toyo RT Trail tire, with a factory wheel weighs ~80lbs. I have it mounted on the tailgate with no modifications, for nearly a year now, and have had no issues.

According to specs, your combo will weigh 85 lbs, unless you choose poorly, and get load range E.

 

[kah.mun.rah]

I ran a 35" tire mounted to a heavy wheel with two gas/water cans attached to the spare tire down a lot of bumpy off-road trails with no issues with the stock gate or hinge. Jeep will never say that beyond what they provided as stock is "ok" and the internet (especially tailgate support vendors) will use scare tactics to make you worry about it. One other thing to note is that the JL design is a lot better than the JK design and JK owners have been running heavy tire/wheel setups on their stock gates and hinges for 18 years.

 

[The Last Cowboy]

Oh, I forgot to add that I also have a Metalcloak spare tire lift bracket that weighs about another 10 lbs. And, I eliminated the third brake light rack, that saved about 1.5 lbs.

 

[LSJKU]

Currently, I run LT315/70R17 (E) BFG KM3 + 27x8.5 703s that weigh in around 93 lbs. I will be going to an LT37x12.5x17 (E) + 703s that weigh about 104 lbs after completing the required drivetrain mod's.

I installed the tailgate reinforcement, but not out of an abundance of concern hanging 35"/703s off the tailgate. Never had any issues with my 2018 tailgate and 35's. I did it for a little peace-of-mind when I put the 37" combo back there, however false that "peace-of-mind" may turn out to be.

Nice wheels by the way. I'm lovin' the beadgrips.

 

[The Last Cowboy]

Another thing to keep in mind is that one of the more common reinforcements available out there will only add extra weight to the stock tailgate hinges. Very few on the market have any type of modification to the hinges themselves.

 

[LSJKU]

Another thing to keep in mind is that one of the more common reinforcements available out there will only add extra weight to the stock tailgate hinges. Very few on the market have any type of modification to the hinges themselves.

That's a great point. And I may go to a bumper-mounted setup anyway, when I get to that stage of mods.

 

[flick2614]

The stock tailgate can't support sh*t, reinforce it.

 

[rickinAZ]

I've followed Jeep forums for almost 20 years and this is, by far, the most commonly asked question. I always play it safe and reinforce.

But...you'll always get some forum member who claims he carried a Sherman tank on his stock setup for "years" without damage.

p.s. I suspect 95lbs will not cause an issue. That said, my current rig has a 103lb spare running on the optional factory reinforcement carrier. Also be careful of calculating weights from the vendor's specs. My spare should have been 5lbs lighter than it's actual weight.

 

[jadmt]

the stock JL hinge is far superior than the JK hinge.

 

[rickinAZ]

And... Artificial intelligence tells us not to ignore the 2.5lbs of air in my tire. That accounts for half of my discrepancy. . And...before you say I've got too much time on my hands, through the wonder of technology, this took less than a minute.

I asked: "How much does the air weigh in a 35 12.5 17 tire inflated to 30lbs?"

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Determining the precise weight of the air in a tire requires knowing the volume of the air cavity and the pressure and temperature of the air. Since a tire is not a perfect cylinder and its shape changes with pressure, an exact calculation is complex. However, we can use the ideal gas law to make a reasonable approximation.






Approximate Calculation


First, we need to estimate the volume of the tire. The dimensions "35 12.5 17" refer to:

• 35 inches: Overall diameter of the tire.
• 12.5 inches: Section width of the tire.
• 17 inches: Rim diameter.
  
  
  
  
  

To calculate the volume, we can model the tire as a torus (a donut shape) or a hollow cylinder. A simpler, but less accurate, method is to treat the tire's air chamber as a cylinder and subtract the volume of the wheel. The volume of the air inside the tire can be estimated to be approximately 3.47 cubic feet at atmospheric pressure (0 psi) and about 10.55 cubic feet at 30 psi.

Next, we use the density of air. The density of air is not constant; it increases with pressure. At standard temperature and pressure (STP), the density of air is about 0.0765 pounds per cubic foot. The gauge pressure of 30 psi is the pressure above atmospheric pressure (about 14.7 psi). Therefore, the absolute pressure inside the tire is 30+14.7=44.7 psi.

Since density is proportional to pressure, we can estimate the density of the pressurized air as:

Densityinflated≈DensitySTP×Atmospheric PressureAbsolute Pressure
Densityinflated≈0.0765lbs/ft3×14.7psi44.7psi≈0.233lbs/ft3
Finally, multiply the volume of the air at 30 psi by the calculated density to find the weight.

Weight=Volume×Density≈10.55ft3×0.233lbs/ft3≈2.46 pounds
The weight of the air in the tire is therefore approximately 2.5 pounds.

 

[Aonarch]

I've heard people complain about the Mopar reinforcement? Any validity to that?

 

[kah.mun.rah]

The stock tailgate can't support sh*t, reinforce it.

Any examples of anyone having one fail?

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