Is there an easy formula for figuring out how much trailer your truck can pull?  This would be an 05 Dodge Diesel, 3/4 ton, extended cab, long bed 4x4.  And a 3H LQ trailer.  I am not quite sure how to use all the numbers.

Thanks

Your owner's manual is the best source of information. It's not easy to give a blanket answer as to what the capabilities of a truck are. There are many options and variables that will change the ratings, drive train, suspension, tires etc.

Many 3/4 ton trucks easily pull a three horse LQ. Then again, the size of your LQ will partially determine what the trailer weight is. You will need to know the gross weight of your loaded trailer, in addition to your truck's rating, to see if the results are compatible.

Gard

No, not really.  But I will say a 3/4 ton diesel usually runs out of rear axle capacity before it runs out of GCWR.

Do you know the pin weight on the 3H LQ?

The total trailer weight is divided between the trailer axles and the pin weight (the weight carried by the truck).

The axle capacity is listed on a sticker on/around the door pillar.  Should be ~6000 lbs for your truck.

You cant exceed the gvw of the truck, that's what it weighs.  I assume you mean the GVWR?  I only bring this up because weights/limits are confusing enough without using the wrong terms. 

What is your pin weight, just out of curiosity?

There are generic guidelines, i.e. BP's 10%-15% and GN's 20%-30% but to know for sure you need to;

use a Sherline scale or..........

take truck and trailer to scale house, weigh truck with trailer attached then unhook trailer and weigh truck only.  Subtracting the truck only weight from truck with trailer weight = pin weight.

I would use the scale house option in your situation as I suspect you are pushing the limits of your rear axle.  Some scales you can pull the whole rig on and have all the axle weights read at once, that would be the quickest way to find out if youre overloaded or not.

I was very surprised when I weighed my LQ trailer after I bought it, and strongly recommend everyone get an acutal scale weight on a LQ trailer before they buy.   Mine is nearly 2x the weight of my non-LQ trailer that was the same make and model.  The dealers don't always have accurate numbers, and may even give weights BEFORE LQ are installed because that is what the manufacturer provided. 

No. 

 Take your 5000# GN trailer example.  Say a 20% pin weight, this means on the scale 4000# will be supported by the trailer's axles and 1000# will be supported at the pin/coupler/carried by the truck.

Here's a link to a trailer towing rating web site. Search under 2005 for your truck. The towing ratings are listed at 13, 200# to 13,600#.

http://trailmanor.com/WebDocs/Camping-Towing/TowVehicles.htm?gclid=CMbUyJns5pcCFQHHGgod0wcEDg

Again you will have variables in the ratings. Some 3/4 ton 4x4's have one ton axles. The optioned tires can also be one ton rated. That is why you need specific ratings and the actual weight of  your trailer to determine your truck's capabilities.

The usual stated 25% percentage of a GN's trailer weight equaling the tongue weight, is just a rough estimate, as is 10% on a BP trailer. If you have a 4' or 15' short wall LQ, these percentages will vary greatly. The actual weights on the hitch ball, will differ from length to length and manufacturer to manufacturer.

Gard

Thanks for looking.

Yes.  The tires will have a rating on them as well, it SHOULD match the axle rating. 

lindszo..

The owner's manual of your truck should tell you how much you can tow. It will also give you gross combined weight rating GCWR (the most your truck and trailer can be when loaded) and your gross vehicle weight rating (GVWR).  You need to know how much your truck weighs. That is usually on your owner's registration. Your GVWR and GCWR should be on a data plate inside one of your doors.

If your 3H trailer is a GN, you need to know how much (%) of the loaded trailer weight will be on your truck. That's what others have called "pin weight" and tongue weight. It is essentially the truck's payload (along with passengers and anything else you put in the truck).

To find out what your PAYLOAD is you subtract the weight of your truck from its GVWR. The difference is your payload.

I'll give you my numbers for an example and then you can replace those with your own.

My GN trailer manufacturer says to estimate 15 - 20% tongue weight. My trailer is 5100 pounds empty. With 1 horse, water, hay, etc. camping equipment, let's say that goes up to 7000 pounds. 20% of that is 1400 pounds. That becomes my payload or pin weight.

My truck is capable of towing 9300 pounds, so the 7000 is under that. My truck weighs 5600 pounds and the GVWR is 7200 pounds. 7200 minues 5600 leaves me 1600 pounds payload. So I'm under that at 1400.

To double check, my GCWR is 15,000.  The loaded trailer is 7000 pounds and the truck is 5600 pounds. Together they weigh 12,600 pounds, which is under the GCWR of 15,000.

Hope this makes it a little bit easier for you to determine.

And for all of you out there that are going to get into the GCWR thing and wonder what my GVWR is for the trailer - just back off.   (where's the emoticon with the cowboy with 2 pistols? LOL) It does nothing to answer the OPs question. Because yes, if I add up the allowed GWR of the trailer with the truck, I'm over the 15,000 for the truck if I ever loaded the trailer to it's max amount.

Need more info than that. What is your truck rated to tow? Someone here posted a link so that you can look up your truck's towing capacity.

And then, how much does your truck weigh? What is your truck's GVWR?

Disclaimer, Im going to make some broad statements here;

A typical 3/4 ton pickup has 3000# "payload" capacity on the rear axle.  This is found by subtracting the empty rear axle weight (usually just under 3000#) from the rear axle rating (usually just over 6000#). 

If one so desires they can use the GVWR - GVW = payload, but that will cut you way short of what this pickup will do.  Using that formula her Dodge, and my GMC, have "payloads" of just under 2000#.  So with only 2000# payload and a 20% pin weight we would be limited to 10000# trailers.  Now we all know you dont need a dually for only 10000# of trailer..........

The GCWR has 'little' bearing on the situation as these modern diesels have way more power than necessary to motivate the conservative factory "tow ratings". 

As long as no axle ratings, truck or trailer, are exceeded that rig would be fine...........however since the empty trailer is 10000# and it has LQ I suspect the loaded pin weight will be VERY close or over 3000# and will overload the rear axle on the 3/4 ton in question.

Now before anyone starts screaming foul about the GVWR and GCWR set by the manufacturer being law and must be followed, I will refer you to your local DMV.  And please check with them BEFORE you try and start that discussion here.  My pickup is registered in the state of SC for a GCWR of 25,000# despite GM rating it at only 22,000#.  I have friends and family all over the country and so far all states will register pickups in a "similar" fashion.