Towing Capacity Question

[pongolo]

I have a 2003 Expedition with the 4.6L engine. Per the owners guide, my maximum trailer weight towing capacity is 6215 lbs. I used to tow a 21' boat with no problems a few years ago which probably weighed in at around 5000 lbs with trailer.

I am looking to purchase a 23' boat with a heavier overall weight. With a fully loaded rig, I'm looking at a trailer weight of about 6800-7000 lbs. I am in Florida and have no hills to climb. My concern is not necessarily on-road towing but actually being able to pull the boat out at the ramp. The weight should be lower at the ramp due to fuel burn but it'll still be over the 6215 lbs limit. Is there anything I can do to increase the weight capacity? I looked at an axle ratio change but I'm not sure if that will change my capacity since the manual states a 6215 lbs limit for all axle ratios. Can a programmer help?

Thanks,
Freddie

 

[06EXP]

Need to know a couple of things......do you have 4WD or atleast a LS Diff? The question may not be whether or not it will pull it out of the water as rather will it have the traction to pull it up the wet ramp. I'm sure in low gear you would probably have enough power to pull it up but if the tires start slipping you would never get it up. You may be able to throw a locker in the rear and be fine, but I'm not sure. Someone with more expertise should chime in and give a better answer.

 

[pongolo]

It is a 2WD. According to the certification label, the axle is listed as H6 which I believe is a limited slip 3.73 ratio axle.

Thanks,
Freddie

 

[Stoned06]

That's heavy for a 23 ft boat. Mine is a 24 1/2 ft cuddy cabin, and with a 1000 lb trailer I am right at 6000 lbs with 62 gallons of gas, water, etc. I have the 5.4, and it pulls up the ramp with no issues. But on STEEP ramps, I usually switch to 4Lo just to make sure I have no problems.
One thing to keep in mind is if you have surge brakes on the trailer, you can NOT get a weight distributing hitch to increase your towing capacity/tongue weight. I don't know if the capacity weight you quoted was with one or not, but something you should think about beforehand.

 

[pongolo]

Here's how I arrived at the 6800-7000 lbs (using the max capacity of gas and water):

Boat: 3400 lbs
Engine: 600 lbs (outboard)
Gas: 780 lbs (130 gallons)
Water: 200 lbs (25 gallons)
Trailer: 1200 lbs (my estimate)
Total: 6170 lbs

I added an additional 600 lbs for gear and other things I may have onboard. Granted, it may be much closer to 6500 lbs than 7000 lbs but I want to make sure I don't underestimate. Also, I have to account for the weight of any gear in the Expedition.

 

[06EXP]

Well the limited slip will definately be better than an open diff, but the key word is "limited". If you wanted to be sure that the rear was locked then throw a selectable locker in and then you KNOW that you are getting maximum traction to the rear.

Unless someone has the exact same setup as you and has experience with the situation you are asking about, then you won't know until you try it.

I have seen a Jeep Grand Cherokee with a V8 and 4WD pull out a 38' cigarette boat before (never thought it would but sure enough he pulled right out)! Did look really wierd that huge boat behind that little suv.

 

[pongolo]

Could you explain how the selectable locker is installed? How much do those run?

 

[06EXP]

Check out this site http://www.arbusa.com/Products/Air-Lockers/Features/12.aspx ARB Air Lockers are one of the most well known in the off-road world. Although they are not just for off-roaders as they are for anyone who wants 100% traction from their axle. The reason a selectable locker is so great is that when locked you get full traction of both tires turning no matter what, but when you don't need full traction (normal driving on street) you turn it off and you are back to your normal axle. As far as cost I can't say as I have never had one installed, but I would say it may be cheaper than doing a axle gear swap.