Tow rating

ridg3runner

ridg3runner

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Does anyone happen to know how a vehicle manufacturer determines the towing capacity of a vehicle? Is the axle size a factor in their ratings or is it just engine size and weight of the vehicle? Just one of those things I've often wondered about:D

We are Jeep..Resistance is futile..
 
As far as I know, the axle size does play into it, not just from a breaking axle shafts point of view, but the actual size of the housing and the bearings being able to carry the extra weight. The towing capacity will also change with your ring and pinion, but I think the ultimate limiting factor is the weight of the vehicle.. And maybe the brakes..

And I know you know this, but I'll say it for anyone who might not know;

It doesn't really matter if you have 400hp and "can" pull 10,000 pounds, it's being able to control it once it's going that puts a rating on things.. When you put a bunch of tongue load on your rig without a weight distributing hitch, it takes all the traction off the front end and you have terrible braking and steering... Very dangerous.




05 Tj, long arm, one ton, lockers, winches, 39.5" Iroks
 
One of the reasons why I asked this question was because of a pic someone posted awhile back of them pulling a queen on a 2 axle trailer with a JKU. There's no way my little 2dr could do that from the factory.

We are Jeep..Resistance is futile..
 
what Dave said is very true. i am able to tow my huge 25' boat (Larson LXI) from my place to the ramp down the street but i will never tow it any farther cause it is wayyyy out of my jeeps towing capacity and makes it really unsafe
 
David1tontj said:
As far as I know, the axle size does play into it, not just from a breaking axle shafts point of view, but the actual size of the housing and the bearings being able to carry the extra weight. The towing capacity will also change with your ring and pinion, but I think the ultimate limiting factor is the weight of the vehicle.. And maybe the brakes..
Click to expand...

That being said, do you think the towing capacity pretty much stay the same for our JKUs with 4" lift and 37" tires with 5.13s and the extra weight from bumpers, winch, etc? I have always been curious what all the modifications do to the towing capacity of a JKU.
 
Doknocker said:
That being said, do you think the towing capacity pretty much stay the same for our JKUs with 4" lift and 37" tires with 5.13s and the extra weight from bumpers, winch, etc? I have always been curious what all the modifications do to the towing capacity of a JKU.
Click to expand...

Just my opinion- but I would think your gears have equally offset your bigger tires... So there is no towing advantage of your lower gears..

Your brakes will not work as well with bigger tires, so I would say that is negative points

As far as the added weight, I would say it probably helps you on the front end for control, but also adds to the total vehicle weight therefore canceling each other out in my book..

Ultimately- if you exceed the rated tow capacity, even if you think you've made compensations for it, you are in a bad place as far as liability.. If you end up losing control of your vehicle for whatever reason, and end up causing property damage, or worst case scenario you hurt someone, you are gonna be in huge trouble from everyone.. I don't know for sure, but I'd bet that your insurance company could even not cover it.. I wouldn't push it


05 Tj, long arm, one ton, lockers, winches, 39.5" Iroks
 
Doknocker said:
That being said, do you think the towing capacity pretty much stay the same for our JKUs with 4" lift and 37" tires with 5.13s and the extra weight from bumpers, winch, etc? I have always been curious what all the modifications do to the towing capacity of a JKU.
Click to expand...

In theory, i'm thinking it would drop as soon as you add the bigger tires assuming a big brake kit hasnt been added yet.

We are Jeep..Resistance is futile..
 
like david said, axle housing plays a role in it, same with suspension ability, braking ability, and over all weight. so if you wanna tow more just double your frame up put 2.5 ton axles on it with the biggest brakes you can find and put an air suspension system on it! :thumb::yup:
 
My comment was in jest of your post saying that you would upgrade to 20 000#.
It seemed funny at the time, obviously it is not....
Apologies for the confusion.
 
ssgp2 said:
My comment was in jest of your post saying that you would upgrade to 20 000#.
It seemed funny at the time, obviously it is not....
Apologies for the confusion.
Click to expand...

blame falls on me as well, but when it comes to modifying anything im pretty serious for future reference:thumb:
 
ssgp2 said:
The standards are explained in this article.


http://www.caranddriver.com/feature...-sae-trailering-standards-explained-tech-dept
Click to expand...

That's a great article and confirms what I've maintained for a while on the JK, based on what a Jeep engineer told me. He advised the JK is underrated in the US on purpose mainly due to liability and the almighty plaintiffs attorneys.

He also advised it could not maintain speed going up that grade referenced in the article or when they tested on I70 west out of Denver. He advised the drivetrain is more than capable. The cooling system is marginal, mainly in need of aux tranny cooler. We talked about how a liberty had a 5k rating and he sort of shrugged and side stepped the question I had as to why...

The brakes are more than adequate on the JK. Quite a few states have laws that if your trailer is x,xxxlbs or more, you must have some type of trailer brakes. Our old pop up was 3,500lbs and I had zero problems stopping. Electric trailer brakes are quite nice.

Braking was already mentioned above, so I'd have you compare today's brakes on a JK compared to a vehicle as recent as a WJ grand Cherokee that had a tow rating of 6,500lbs with comparable brakes. Could even be argued they were inferior what with esc and trailer sway control built in to the JK with tow package.

Set up right, aux transmission cooler, trailer brakes, I'd feel safe myself pulling 5,000lbs. Know your own limitations and be courteous to any traffic that wants to pass you. For legal purposes, don't exceed the factory rating.


Sent from a a few tin cans and some string.
 
I pull a 20 foot 2 axle trailer loaded 6 bails high with my jeep when a truck isn't available(that's about 5,500lb of hay for you city boys) and it does just fine. Now it's no dually and I wouldn't drive too far down the highway with it but it's handled the back roads so far without any problems. Trailer brakes all the way.
 
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