"Sport S,ing" a Rubicon . . . ? and Towing Thoughts

[bgenlvtex]

If 650 lbs is the margins to make or break it for me with payload or towing, I would be looking for another vehicle. Quite frankly, I do not like going over 75% of rated capacity to begin with, let alone taking it to the max limit.

My unscientific and entirely proprietary personal number is 60% dry. That could probably be reasonably extrapolated to 75% loaded up as maximum.

I'm not saying that manufacturers don't test to a reasonable, repeatable and verifiable standard, I'm just saying that standard is unrealistic bullshit founded in marketing not reality.

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[Bobzdar]

My unscientific and entirely proprietary personal number is 60% dry. That could probably be reasonably extrapolated to 75% loaded up as maximum.

I'm not saying that manufacturers don't test to a reasonable, repeatable and verifiable standard, I'm just saying that standard is unrealistic bullshit founded in marketing not reality.

It's SAE J2807, so a spec and is fairly realistic, reading through it. Here's the summary:

"Here are the main test methods trucks would be measured on as per J2807:

• Cooling capability on a long highway upgrade modeled on the Davis Dam grade on Arizona SR 68;
• Launch and acceleration performance on a level road and a 12 percent upgrade;
• Combined handling performance – understeer and trailer sway;
• Combined braking performance – stopping distance and parking brake-hold on grade; and
• Structural performance for the vehicle and hitch or hitch receiver.

New calculations for trailer weight ratings: In addition to the performance standards, SAE J2807 also uses a specific set of assumptions to calculate maximum trailer weight ratings:

• For light-duty full-size pickups (GVWR < 8,500 lbs.), SAE J2807 assumes that the tow vehicle includes any options with higher than 33 percent penetration;
• It assumes there is both a driver and passenger in the vehicle, each weighing 150 pounds;
• It assumes that tow vehicles also include up to 70 pounds of aftermarket hitch equipment (where applicable); and
• For conventional trailer towing, SAE J2807 assumes that 10 percent of the trailer weight is on the tongue."

I don't know what you think is unrealistic BS in that, but it's pretty straightforward. The part the Gladiator struggles with is the first bullet, at least based on every interview with FCA engineers I've seen.

 

[NoBigDeal]

I'm sure this has been said, so sorry for that, just felt felt it needed to be said/again. You can strip it down, reinforce the frame, swap the axles, add new suspension/airbags, swap a big cummins and transmission, throw a 150 gal aux fuel tank in the bed, add a goose neck hitch, and have the ability to cross-country tow 20,000+lbs. The one thing you can't change, regardless of how much money you throw at your rig, is the numbers printed on the sticker on your door.

 

[BreakFixRepeat]

Also you can do whatever you want to make anything pull more and more and more until you have to hit the brakes. The more it weighs the more inertia you gotta get stopped. And the extra stuff in the Rubicon factors in. Just take a Rubicon and a Sport S with the max towing package both empty and stop them both from 60 as fast as you can. The Sport is gonna stop faster because is weighs less and has less rotating mass because of the smaller tires.

 

[futzin']

So I loaded this up with my 4wheeler, a couple of coolers, and most of my gear/weight that would ever be in the thing. Towed it around for a while on 2 lane and interstate with the Pentastar in our 2015 Durango Citadel AWD to try to get a sense of how a JT would do. Tow rated at 6200 lbs. Truck was empty but for me. No weight distribution hitch. No sag. Trailer weighed in at 4440 lbs, per Pilot scale. Durango specs are 5100 lbs weight, 3.45 gears, 120" wheel base, 295 HP.

Actually, it felt pretty good. Much better than our 25' camper that I occasionally tow 2 miles at a time. (Camper is heavier and has more tongue weight.) I shifted manually with the paddle shifters. I anticipate shifting manually with the JT as well. There was no sway; was very stable. I ran 65 - 70 mph on the interstate, mostly in 6th gear. Fairly level, though. Downshifting was a must on the upgrades, but it responded well when shifting down. Fifth gear was sufficient, went to fourth once. Got 12 mpg.

My gut tells me that the JT Rubicon should tow this trailer similarly. But the boxiness of the Jeep, and the increased air against the trailer frontage won't help. Thinking/hoping the 4.10s and longer wheel base will offset. Wondering how the Rubi suspension will respond vs. the Rango.

So do you guys think this was a reasonable test in lieu of actually hooking up to a Gladiator?

 

[KVJ]

I have a Sport S and thought the brakes were the same as a Rubicon?

 

[Astephan1284]

I'm no expert, but I don't think the suspension is the issue. It's the added weight from all of the armor underneath the Rubicon. If you removed the off roading armor/protection stuff underneath you're going to get pretty close to Sport S for towing and payload.

I read an interview with one of the FCA engineers assigned to the towing project for the gladiators. He stated that it was an airflow issue. Hence why the grill openings on the gladiator are wider than the JL and the honeycomb pattern also has larger openings. They're designed so that they would get more air flow into the cooling system to boost tow numbers. He also stated that the Rubicon lost some pounds due to the skid plates blocking part of the lower access air that gets sucked up into the cooling system form underneath the bumper/grille whereas the sport (Lacking said skid plate) got just a tad more air flow to pump the numbers up.

 

[5JeepsAz]

Good thread. So, off topic but hoping to get an answer for my 64 JT, m/t 3 speed, geared low, 4:09 or 4:27. I want to increase top end speed. If I roll taller tires, how much mph can I gain? Here's the basic truck (mines not lifted, but similar):

 

[Texops]

Good thread. So, off topic but hoping to get an answer for my 64 JT, m/t 3 speed, geared low, 4:09 or 4:27. I want to increase top end speed. If I roll taller tires, how much mph can I gain? Here's the basic truck (mines not lifted, but similar):

Regear to 373 or swap a 4 or 5 speed transmission , i really love those old Gladiators

 

[futzin']

So I loaded this up with my 4wheeler, a couple of coolers, and most of my gear/weight that would ever be in the thing. Towed it around for a while on 2 lane and interstate with the Pentastar in our 2015 Durango Citadel AWD to try to get a sense of how a JT would do. Tow rated at 6200 lbs. Truck was empty but for me. No weight distribution hitch. No sag. Trailer weighed in at 4440 lbs, per Pilot scale. Durango specs are 5100 lbs weight, 3.45 gears, 120" wheel base, 295 HP.

Actually, it felt pretty good. Much better than our 25' camper that I occasionally tow 2 miles at a time. (Camper is heavier and has more tongue weight.) I shifted manually with the paddle shifters. I anticipate shifting manually with the JT as well. There was no sway; was very stable. I ran 65 - 70 mph on the interstate, mostly in 6th gear. Fairly level, though. Downshifting was a must on the upgrades, but it responded well when shifting down. Fifth gear was sufficient, went to fourth once. Got 12 mpg.

My gut tells me that the JT Rubicon should tow this trailer similarly. But the boxiness of the Jeep, and the increased air against the trailer frontage won't help. Thinking/hoping the 4.10s and longer wheel base will offset. Wondering how the Rubi suspension will respond vs. the Rango.

So do you guys think this was a reasonable test in lieu of actually hooking up to a Gladiator?

bump

 

[5JeepsAz]

Regear to 373 or swap a 4 or 5 speed transmission , i really love those old Gladiators

They offered a hi low overdrive, making it a six speed. No change needed otherwise. Added 10mph. Am I right to try that before regearing?

 

[WXman]

I'm sure this has been said, so sorry for that, just felt felt it needed to be said/again. You can strip it down, reinforce the frame, swap the axles, add new suspension/airbags, swap a big cummins and transmission, throw a 150 gal aux fuel tank in the bed, add a goose neck hitch, and have the ability to cross-country tow 20,000+lbs. The one thing you can't change, regardless of how much money you throw at your rig, is the numbers printed on the sticker on your door.

Yep, 100% true and it has been stated on this forum quite often, and this is the reason that I personally feel the Sport with Max Towing is the ONLY way to go if you ever think you may actually haul or tow with the truck.

Better to have max payload and not use it than to need more payload and not have it.

 

[eternus]

Yep, 100% true and it has been stated on this forum quite often, and this is the reason that I personally feel the Sport with Max Towing is the ONLY way to go if you ever think you may actually haul or tow with the truck.

Better to have max payload and not use it than to need more payload and not have it.

Except, if you're towing under the amount posted on the door, who cares what it says. That sticker is there for legal purposes... so you only need the Sport S Max Tow if you're going to tow MORE than the posted 7000 for a Rubicon, but still less than the 7600 on the Sport S. If you're honoring the wisdom of 60% of max tow (which I favor) then its 4200 vs 4560 (only a 360 lb diff.)

As is always the case, using your brain rather than the numbers posted by a marketing team are what's most important.

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