Is the payload under rated

[NC_Overland]

I’m not sure understand what you did. What model Gladiators did you use? And you loaded them identically with 1,200 lbs each time? And they were both new and stock?

Yes. My Jeep with the stock springs and then the rubicon LE springs. Night and day difference.

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[MPMB]

Idealy I'd like to see it actually broke down WHY payloads are what they are. Like the actual data;

"When we tested the rotarygirdle, we found that the longevity of the scirmlbuckle was significantly reduced at loads over 1,213 lbs, and we saw significant scoring of the spherical shaftnickle coating."

We'll skip the original meaning - the historical meaning of 1/2 ton, 3/4 ton, etc., which has evolved and basically lost all meaning and is irrelevant today.

Payload is simply the GVWR - Curb weight of vehicle. So if your door sticker says your JT weighs 5075, your payload would be 6250-5075=1175.

The appropriate question is how did "they" come up with the GVWR of 6250#? Well class, open your books to page 394.

Long ago the government divided vehicles into classes for EPA gas reasons, then oversight (FHA), etc. Originally it was specified that trucks had to be GVWR/payload-limited to use unleaded fuel, but then we got rid of leaded fuel altogether and it became a moot point. Basically, that gave us consumer trucks Class 1 - 3. Class 4 to Class 8 are commercial trucks (F450/4500 & up).

Today, mid-size trucks are Class 1 trucks and have a maximum GVWR of 6000#. "GVWR includes total vehicle weight plus fluids, passengers, and cargo." GVWR over 6000# gets bumped up to Class 2a, with the usual 1500/F150 trucks.

However, Jeep has engineered the Gladiator Rubicon and Mojave models with heavy duty axles that exceed the 6000# GVWR limit, pushing the GVWR to 6250#. Here are the official Jeep GVWR numbers for Gladiator models. This is because these models (Rub/Moj) are designed for off-road use, not on-road, fleet use, etc. However Jeep wants to justify it to exempt these models from classification.

Checking numbers online, though, I do believe Jeep has transposed the numbers on the website under the model specs, since they list both the Rubicon and Mojave trims as having payload and towing capacity of 1700# and 7700#. Sport S, however, is 1050# and 4500#, respectively. Pretty sure someone done goofed on that.

The big caveat with all of this is these numbers are for the government's bureaucracy, not structural integrity. That's why when you add the weight capacity of each axle you get a number greater than 6000#/6250#. Unfortunately, people tend to misunderstand things and misapply things, then those mistakes end up becoming case law.

The point is that overall, there is an arbitrary ceiling placed by the gov't, established originally for something that no longer exists, on the payload capacity.

So in short, how they determined payload is along the same lines as why you cut the ends off the ham when you roast it.

 

[MPMB]

I don't think there is much difference is spring rate among the stock springs.

There likely isn't.

Diesel gets its own springs, at least up front for the heavier engine. Rubicon gets its own. Sport & Overland get taller but softer springs. Mojave gets its own spring.

The number of various parts can be all sorts of things, considering the JT launched during covid and many places shut down.

Unless someone wants to spend a week testing various springs P/N with a spring tester to verify, I doubt we'd find a huge difference between spring rates within a model line. Maybe 100# between a Sport and Rubi or EcoD.

 

[NC_Overland]

There likely isn't.

Diesel gets its own springs, at least up front for the heavier engine. Rubicon gets its own. Sport & Overland get taller but softer springs. Mojave gets its own spring.

The number of various parts can be all sorts of things, considering the JT launched during covid and many places shut down.

Unless someone wants to spend a week testing various springs P/N with a spring tester to verify, I doubt we'd find a huge difference between spring rates within a model line. Maybe 100# between a Sport and Rubi or EcoD.

Rather than speculating, I can tell you first hand that if you get the stiffest rubicon or max tow spring, it’s very different. There are like several different spring rates on the rubicon alone. Others who don’t regularly tow and haul with their gladiators might not see a big difference, but I definitely did.

 

[NC_Overland]

The biggest limiting factor of the Rubicon suspension with the highest spring rate is the Fox shocks. I wore them out pretty fast. They always did pretty well under load or when you pushed it cornering (unloaded), but they had too soft of a ride in normal driving and I eventually wore them out at 60k miles because I just don’t think they were designed for the towing and hauling I did with mine regularly for years. I recently put 5100s on it and it’s great now. Better than new. The 2nd and 3rd pic are roughy 1200 lbs in the bed. Accordingly to Home Depot that tractor/trailer combo is 6800 lbs. Those are just the pics I have because it was for personal projects.

 

[MPMB]

Rather than speculating, I can tell you first hand that if you get the stiffest rubicon or max tow spring, it’s very different. There are like several different spring rates on the rubicon alone. Others who don’t regularly tow and haul with their gladiators might not see a big difference, but I definitely did.

As someone who spent almost 20 years dealing with springs on racecars that competed on multiple tracks that almost tripled in length and speed, calculating effective spring rates, roll couple distribution, roll centers, etc., I think I have a good enough handle on springs.

One user here has tested their springs: Rubicon spring rates measured | Jeep Gladiator (JT) News, Forum, Community - JeepGladiatorForum.com. You're looking at 130#/in vs. 139#/in. in the front for his JT config. For a slightly heavier JT, the front spring rates might bump up 10#-20#/in. Adding 40# more bumper (plastic to steel) does not mean you add 40# more spring rate. That's not how it works.

The ~10# difference between the front is well within error tolerance, meaning the springs are essentially the same spring rate.

Furthermore, as someone who has an aftermarket kit, there isn't a L/R spring designation with aftermarket kits from my supplier. And other suppliers don't designate L/R, either. Clayton, for example. They even list their Overland+ spring rate, which is an equal 188#/in for each, 50# more than stock Rubicon.

50# of spring rate between a stock rate and a spring for a built, off-road JT is not much of a difference. That can easily be compensated by using spring rubbers if one needed to.

So yes, Jeep may have a multitude of springs for the combination of weights a JT may be - plastic bumper, manual, soft top, plastic fenders vs. plastic bumper, lockers, soft top, body-color fenders vs. steel bumper, lockers, hard top, body-color fenders. But it's not going to be 100#/in difference or 150#/in between the lightest and heaviest.

 

[MPMB]

The biggest limiting factor of the Rubicon suspension with the highest spring rate is the Fox shocks. I wore them out pretty fast. They always did pretty well under load or when you pushed it cornering (unloaded), but they had too soft of a ride in normal driving and I eventually wore them out at 60k miles because I just don’t think they were designed for the towing and hauling I did with mine regularly for years. I recently put 5100s on it and it’s great now. Better than new. The 2nd and 3rd pic are roughy 1200 lbs in the bed. Accordingly to Home Depot that tractor/trailer combo is 6800 lbs. Those are just the pics I have because it was for personal projects.

The Fox shocks from '20-'21? Yup, those sucked. I had a heavy RTT (~175lbs) on a tall bed rack and the shocks couldn't handle it.

 

[JeepinPete]

Payload is simply the GVWR - Curb weight of vehicle. So if your door sticker says your JT weighs 5075, your payload would be 6250-5075=1175.

This is yet another example of the gov messing things up. What you state is exactly what payload should be. That yellow sticker in the door jam doesn't necessarily agree. I went through this once upon a time setting up a Durango to tow at its max capacity. In no way, shape or form could I meet the sticker number, but hook everything up and take it to the scales and what do you know, all the axle weights and GWVR are in spec.

Lesson learned, for any future endeavors, I will ignore that sticker and deal with GAWR, GVWR, and GCVWR.

 

[NC_Overland]

The Fox shocks from '20-'21? Yup, those sucked. I had a heavy RTT (~175lbs) on a tall bed rack and the shocks couldn't handle it.

Now that I think about it, maybe the shocks didn’t wear out. 60k miles is when I added my new bumpers, winch, lights, and went from a soft folding cover to a Bakflip MX4. It was probably the extra weight. I retired my truck from working duty and added some of the stuff I’ve been wanting. It’s great with my 5100s.

 

[MPMB]

Now that I think about it, maybe the shocks didn’t wear out. 60k miles is when I added my new bumpers, winch, lights, and went from a soft folding cover to a Bakflip MX4. It was probably the extra weight. I retired my truck from working duty and added some of the stuff I’ve been wanting. It’s great with my 5100s.

Yeah, not wear out, but definitely ill-equipped for anything many of us use trucks for.

I was at 40k when I put my lift on and I had zero off-road trails; only a couple well-maintained forest service roads. It's been well noted how bad those shocks were if they were stretched anything beyond showroom stock use.

One section of a road leaving our area has a dip or two and the JT would wallow back and forth 5 or 6 times before it settled down. Any decent shock should have that controlled within 2, 3 wallows max. And yes, "wallows" is a highly technical term.

 

[Stan H]

I have a willys edition with a door trim rated payload of 900 lbs.
I picked up a face cord of fire wood from the cottage to bring home which was at least 1000 lbs and drove an hour in hilly terrain.
There was a little squat but the truck drove normal.
No significant acceleration or braking issues. It felt good. Checked gauges all looked normal.

No

 

[Bandit’s Lair]

The Fox shocks from '20-'21? Yup, those sucked. I had a heavy RTT (~175lbs) on a tall bed rack and the shocks couldn't handle it.

I concur. I believe I have those fox shocks on my 21’ Gladiator and they make me think all manner of ill and evil thoughts when I get off the pavement.

 

[NC_Overland]

Mine always performed great off the pavement. They just sucked on road and rebounded too much after I added more weight to my Jeep. They did well for towing and hauling before that. I haven’t done it since I added more weight and now with the 5100s, but I used to haul ass across our pastures at 50-60 mph and not feel anything and be remarkably stable and smooth. It would swallow up a railroad track used to jump in high school and not bottom out or rebound excessively. Never got off the ground like my old S10 blazer. Too much suspension travel. I always thought they performed well when pushed but were too lightly valved when unloaded and street driving.

 

[Bandit’s Lair]

My issue is when I hit a wash. They do good for low and slow just trail driving and on the road they’re alright but I hit a wash about 2 weeks after I bought the thing and wife and I felt like we were in a shake weight even going 10-15 mph. It was killing us. I just think it wasn’t keeping up with the frequency of cycles. Heating up too much and got to the point where it felt like I was only on springs. Planning on very good shocks and springs or just going coil over either or with long arms. I don’t really tow so I wouldn’t be losing much. I have a K2500 GMC Suburban if I need to tow anything. Just have to get it fixed.

 

[Zachanadandy]

My issue is when I hit a wash. They do good for low and slow just trail driving and on the road they’re alright but I hit a wash about 2 weeks after I bought the thing and wife and I felt like we were in a shake weight even going 10-15 mph. It was killing us. I just think it wasn’t keeping up with the frequency of cycles. Heating up too much and got to the point where it felt like I was only on springs. Planning on very good shocks and springs or just going coil over either or with long arms. I don’t really tow so I wouldn’t be losing much. I have a K2500 GMC Suburban if I need to tow anything. Just have to get it fixed.

Not only are they too short stroke, the body is just to small. They heat up and fade quickly as you've noted. Even the 5100s will be too hot to touch and start to fade after a few miles of washboard. The only way to beat that is a reservoir shock and preferably a 2.5". The mojave shocks on the other hand never show any signs of fading even after 40+ miles of washboards at 70 mph. The only factory Jeep shock I've ever run that's worth a damn at speed in the desert (I guess that's why it's the only desert rated Jeep from the factory).

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