Jeep Wrangler Forum banner

1 - 20 of 29 Posts

·
Registered
Joined
·
85 Posts
Discussion Starter #1
We decided to pull the trigger on a Starcraft ar-one 15-rb extreme before the camping season begins. It weighs in at 3033lbs with a full tank of water, battery, and propane canister. Adding in the little gear we store in there I would guess it totals ~3100lbs.

I have a 2013 JKU auto with max tow package (meaning 3.73 gear ratio) and 32" tires. I installed a P3 break controller and 7pin connector to use the trailers electronic drum breaks. All this means I SHOULD be able to tow 3500lbs.

We live at pretty high elevation ~7200ft and went on our first trip about 45 miles away to ~8500ft elevation. With a full fresh water tank and full gas tank with little headwind the Jeep pretty much sat in 3rd gear to keep at 70mph if left to its own decisions. It didn't hunt for 4th ever which I suppose is good, but it was painful sitting at 4000rpm the whole time. It equated to about 9.5mpg... ouch. On the flats on the way back I forced it into 4th and then did all manual shifting and brought the mpg to ~11 which is a little more reasonable. My concern is we intend on doing a significant amount of boondocking and that often means less access to gas. I am concerned my range of ~200 miles is going to create some sweat inducing moments. For now I feel the urge to manually shift but I have read elsewhere in this forum that the computer is quite good at keep trans temps down compared to shifting yourself.

What really confuses me is I know most people say that it is the design of the Jeep that limits its towing capacity such as the hitch mount design and wheelbase, not the engine/trans. I honestly felt really stable the whole time. The Jeep felt "in control" even with a strong (Wyoming for those whom know the winds here) sidewind and passing semi's on a 2-lane highway so safety doesn't seem to be the issue. The limiting factor felt like the engine.

So that brings me to think about the grand cherokee... It has the same engine and yet has nearly double the towing capacity. WTF? I can't imagine towing that kind of weight with this engine. Even with a greater number of gears I don't think the pentastar has the oomf to tow that kind of weight. What am I missing here?

Regardless, I love the trailer and plan on towing it with the Jeep across the west over the next couple of years. I may mount a gas can or two on the trailer to increase my range but I couldn't imagine selling the jeep for something with more horsepower.

We had a great first trip even if it did snow overnight! High elevation Springs can be unpredictable! What are your all thoughts? Am I crazy thinking it is the engine?

20170409_082918.jpg
 

·
Registered
Joined
·
119 Posts
Towing a trailer

My son-in-law is building my off road trailer to tow behind my Jeep JKU.
It is going to be completely self contained with Solar panels, 30 gal water tank, on-demand hot water heater, shower, stove and sink. I was worried about the weight as the dealer told me my Jeep was only rated for 2000 lbs towing with the 3.21 gears. I just purchased some Revolution 4.10 gears that will get me to 3500 lbs towing. I am saving for the Truetracs for the front and rear and the labor for the install.
 

Attachments

·
Registered
Joined
·
85 Posts
Discussion Starter #4
I think part of the problem with a full hardside camper is the frontal wind load. It sticks up substantially above my jeep meaning it acts like a windsail. In my case the trailer has greater ground clearance than the Jeep so I almost wonder if a lift would better align the front profiles and actually help performance when towing.
 

·
Premium Member
Joined
·
16,895 Posts
Jeep has been F'ing with the Wrangler vs the Cherokee line since I can remember. I used to have 4.0's sitting next to each other. My Cherokee and Grand ran like rapes apes. Wrangler with same motor couldn't outrun a fart.
Finally got them to admit they detuned and put a different throttle body to allow the Wrangler down on purpose.
As far as your towing..... Cheapest best improvement would be gears.
 

·
Registered
Joined
·
85 Posts
Discussion Starter #6
Jeep has been F'ing with the Wrangler vs the Cherokee line since I can remember. I used to have 4.0's sitting next to each other. My Cherokee and Grand ran like rapes apes. Wrangler with same motor couldn't outrun a fart.
Finally got them to admit they detuned and put a different throttle body to allow the Wrangler down on purpose.
As far as your towing..... Cheapest best improvement would be gears.
Why would they intentionally make the engine run poorly?
 

·
Registered
Joined
·
119 Posts
I think part of the problem with a full hardside camper is the frontal wind load. It sticks up substantially above my jeep meaning it acts like a windsail. In my case the trailer has greater ground clearance than the Jeep so I almost wonder if a lift would better align the front profiles and actually help performance when towing.
That is what I was worried about too. The trailer being to tall.
My trailer is just around four inches taller than my Jeep. and we made it the same width of the Jeep. I wanted a little more room inside so we went with the tires in the wheel wells. I wont be able to stand up completely in the trailer but I want it to fit in my garage and be about the same height as the jeep so that doesn't bother me, plus I didn't want an excuse to be in it instead of the outdoors.
 

·
Registered
Joined
·
46 Posts
...

What really confuses me is I know most people say that it is the design of the Jeep that limits its towing capacity such as the hitch mount design and wheelbase, not the engine/trans.

So that brings me to think about the grand cherokee... It has the same engine and yet has nearly double the towing capacity. WTF? I can't imagine towing that kind of weight with this engine. Even with a greater number of gears I don't think the pentastar has the oomf to tow that kind of weight. What am I missing here?

View attachment 3562906
The engine and transmission is a small part of towing capacity. You'll typically find that the real limiting factor is the axle carrying limit. Each of your axles is only designed to hold so much weight. The tongue weight of the trailer and anything you put into your Jeep takes away from that capacity.

In other words, it doesn't matter how much engine and transmission you have if the axles can't hold the weight.

I'd be curious to compare the axles ratings on the Cherokee vs a JK. Also, the rear frame design might be stouter on the Cherokee, allowing it hold a higher capacity hitch. The JK hitches are Class III. I best the Cherokee can hold a Class IV. Class IV is also what most trucks can carry, although the heavy duty trucks like F250's have Class V hitches.
 

·
Registered
Joined
·
85 Posts
Discussion Starter #9
The engine and transmission is a small part of towing capacity. You'll typically find that the real limiting factor is the axle carrying limit. Each of your axles is only designed to hold so much weight. The tongue weight of the trailer and anything you put into your Jeep takes away from that capacity.
This kind of ignores what I said... I get what you are saying but what I am saying is, anecdotally speaking, that doesn't feel like the limitation. The engine is working its ass off with 3000lb. How the heck is it suppose to drag 6000lbs?
 

·
Registered
Joined
·
85 Posts
Discussion Starter #10
That is what I was worried about too. The trailer being to tall. My trailer is just around four inches taller than my Jeep. and we made it the same width of the Jeep. I wanted a little more room inside so we went with the tires in the wheel wells. I wont be able to stand up completely in the trailer but I want it to fit in my garage and be about the same height as the jeep so that doesn't bother me, plus I didn't want an excuse to be in it instead of the outdoors.
I am 6'4" and wanted to be able to stand up (mostly). My trailer is jusssttt tall enough for me to stand upright.
 

·
Registered
Joined
·
46 Posts
This kind of ignores what I said... I get what you are saying but what I am saying is, anecdotally speaking, that doesn't feel like the limitation. The engine is working its ass off with 3000lb. How the heck is it suppose to drag 6000lbs?
Same engine - different transmission. Huge difference. The Cherokee has a 9 speed. And while an engine running at 4K RPM while towing is a bit annoying sound wise, that's right in the power band. So it may be loud and slow but the engine can handle it.
 

·
Registered
Joined
·
766 Posts
I've had this travel trailer following me around for the past year or so. I tow with empty tanks but it's still over 3K pounds loaded up.

I take the back roads to the coast and stay at around 55-60mph, about a 4-5 hour trip. I'll typically average around 11mpg. 3.73 gears just like you and I've been doing it with 33x12.5x15 Duratracs.

If there isn't a headwind it will sometimes go into OD on level ground. But not often. If there is a headwind and a bit of a grade I'm down into 3rd gear.

At first it was freaking me out if I spent any amount of time in 3rd doing 3500 rpm or more. But like others said, that's where this engine is happiest.

Makes sense, I went up to Colorado not long ago and those 40mph headwinds between Amarillo and Colorado Springs had me downshifting into 3rd just to stay at 65 - and I wasn't towing anything.
 

Attachments

·
Premium Member
Joined
·
16,895 Posts
Why would they intentionally make the engine run poorly?
Not run poorly, just much less power expressed as speed. The Wrangler has handling challenges so they slow it down.
Been that wat ever since the dust up over the Cj platform and alleged turn-over issues. Thank you Ralph Nader and the 60 minutes types.
 

·
Registered
Joined
·
9 Posts
I've done a little research on the JKU in other markets and the tow rating is higher than it is here. I think a lot of it is the the insurance industry and the fact that most car makers are afraid of the liability. In other markets, Britain and Austrailia specifically, the JKU with the pentastar is rated to tow 4400lbs. The key difference is the size of the front rotors. They are larger in other markets. I just upgraded mine to with the Teraflex big brake rotors and brackets. I tow a 19' travel trailer with mine and it pulls it fine in 4th most of the time. I usually manually shift mine as well. I never had any trans. temp issues even on my trip through the rockies and out west to moab in August. You just have to learn a little less mechanical sympathy for these engines as they do require some revs to get the best out of them. YMMV.
 

·
Registered
Joined
·
9 Posts
Running the Max Tow Package with 3.73's Tires are 285/70-17 Tera Grapplers, which I can't wait to replace. A big help was the Flashpaq to correct the trans shift points.
 

·
Premium Member
Joined
·
16,895 Posts
Running the Max Tow Package with 3.73's Tires are 285/70-17 Tera Grapplers, which I can't wait to replace. A big help was the Flashpaq to correct the trans shift points.
What's up with the tires? You know you can't dangle stuff like that w/o a follow-up :)
 

·
Registered
Joined
·
9 Posts
I just haven't been happy with them. They are terrible in any kind of mud, which unfortunately, where I live is the majority of what I do. They are average in the dry but like to spin up too easy in the rain.
 

·
Registered
Joined
·
85 Posts
Discussion Starter #20
At first it was freaking me out if I spent any amount of time in 3rd doing 3500 rpm or more. But like others said, that's where this engine is happiest.

Makes sense, I went up to Colorado not long ago and those 40mph headwinds between Amarillo and Colorado Springs had me downshifting into 3rd just to stay at 65 - and I wasn't towing anything.
I guess I may have to settle with the abysmal mileage and noisy engine. I may try mounting two jerry cans to help with the range. I intend on going to some pretty backwoods locations here in Wyoming where getting gas can be an issue.

Heck, much of the Denver area is nearly a half mile lower in elevation than where I am so it can't help having Wyoming wind and elevation.
 
1 - 20 of 29 Posts
Top