I have a 2500 short bed quad cab 4x4 diesel 6 speed. Can I tow a gooseneck w/ it? Will the toolbox have to be removed? How heavy of a gooseneck? I hear they need 25% of their weight on the pin. Looked at my door sticker & it said: GVWR 9000, GAWR front 5200, GAWR rear 6000. So, assuming that the truck weighs 7400 lbs. (can someone confirm this guess) & the weight distribution is 65% front & 35% rear, Based on GVWR, I can pull a 6400 lbs. trailer & based on GAWR rear, I can pull 13640 lbs. trailer if I want to stay legal. Is this correct? 6400 lbs. seems light!

Are most of you guys concerned about GVWR or GAWR? Why such a big differerance between teh GVWR & GAWR capabilities?

 

I have the same truck as you except with auto. I have an auxiliary tank/toolbox combo and it takes up 18" of space as measured back from front top of bed rail to rearmost edge of tool box. I have a shortbed and B&W turnover ball GN hitch. With GN hooked up I have about 7" clearance between front of GN coupler and tool box. My GN trailer (horsetrailer) has a tapered front and clears everything just fine (both cab and toolbox).

I did the exact same as you and started doing the weight math - it gets scary! I weighed my truck without me in it and it weighed about 7,250 lbs clean (without driver and about 10 gallons of fuel). My empty Gn trailer weighs 5,500 lbs. However if I go to full fuel (65 gallons = 475 lbs) plus driver, passenger, luggage, etc my truck gets over 8,000 lbs real quick! With the trucks GVWR set at 9000lbs and subtracting the truck loaded weight you get less than 1,000 lb available payload. My loaded GN is expected to weigh in around 8,500 lbs (I really need to get it weighed loaded). Now is where it gets interesting...If you figure 25% of the trailer weight in on the GN (pin weight) You are looking at 2,125lbs. That puts me at 1,125 lbs over the truck's 9k GVWR but about 4,600 lbs under the maximum tow rating of 13,050. Now comes the tricky part, the front GAWR is 5200lbs and the rear is 6000lbs. The truck weight, as built from the factory, is distributed 60% to front and 40% rear (actually .6059 frt and .3941 rear). Now the question is: What is the percentage of weight transferred to the axles fore/aft from the GN coupler, which in a short bed is sitting maybe 3" in front of the rear axle centerline? I ran some estimates using numbers of 20/80% transfer fore/aft of the GN pin weight. I am under on the rear axle and slightly over on the front axle ratiing.

The more I dug into this it the more confusing it got. I finally had to build an Excel spreadsheet with several formulas to calculate payload and axle weight ratings depending on how much fuel, luggage, etc. I have as well as how much weight I load in the trailer. It uses conditional formula formatting and will turn various weight boxes red if I go over the factory ratings. It certainly gets my attention!

However, when fully loaded and towing my rig on the road it seems very well balanced and the truck seems to hardly notice the added weight and suspension feels great. Needless to say, I will never run anything less than E rated tires on the truck aired up to 80 PSI.

 

Hello;
I too am doing a lot of math lately! Since you have already made an Excel Spreadsheet, I was wondering if you could attach/post the spreadsheet?

Thanks so much.

Jerry

 

Good Answer - thanks for the reply. The weight transfer is easy to figure out - I too put a spreadsheet together comparing a bumper pull to a gooseneck. I used the following assumptions:

Truck weight 8000 lbs. w/ 60/40 front/rear distribution
wheel base = 141"
Distance from rear axle to bumper pull tongue load point = 54"
Distance (In front) between Kingpin and rear axle = 3"
Trailer Weight = 10,000 lbs.
Travel Trailer tongue weight = 15%
Gooseneck Pin weight = 25%

The results for a Bumper Pull:
Total rear axle load = 5274 lbs. - OK (GAWR rear is 6000)
Total front axle load = 4226 lbs. - OK (GAWR rear is 5200)
Total Axle Load = 9500 lbs. - NOT OK (GVWR is 9000)

The results for a Gooseneck:
Total rear axle load = 5647 lbs. - OK (GAWR rear is 6000)
Total front axle load = 4853 lbs. - OK (GAWR rear is 5200)
Total Axle Load = 10500 lbs. - NOT OK (GVWR is 9000)

Knocking down the trailer weights until everything was OK (i.e. legal) the max trailer weights are:
Bumper Pull: 6650 lbs.
Gooseneck: 4000 lbs.

So, legally, the size gooseneck that you can haul would really leave you with a bumper pull. The bumper pull trailer legally lets you haul a trailer that is 50% heavier than the gooseneck. Notice all axle ratings are OK, it's just the GVWR that is exceeded!

I am wondering if a truck outfitter can legally rerate our trucks. In addition, If I would put on some helper springs & Rickson's, would they rerate the truck so I can legally tow up to the increased capacity. Keep in mind that the duallys have the same axles, brakes, chassis, etc. and their ratings is GAWR front 5200, GAWR rear 9350, GVWR is 21000 (23000 if you have 4.10).

 

If you move your trailer axle forward or rearward it changes your GN weight. This is what i do with my rig.But don't know any trailors that do this except 18 wheelers.

 

Yes, that's true, but on most goosenecks, you can move the axle easily, and secondly, I always thought that you wanted to put not less than 25% of the trailer weight on the pin.

 

I think the only acurate trial and error, given all the variables including how loads aren't always in exact placement on/in the trailer (especially live animals) is to find a truck scale with three platforms to measure front, rear and trailer axle weights.

He's right in that calculating axle weights is tricky. Paper weights and real weights sometimes can differ a hell of a lot.

 

ajpulley is wright truck scale,because this is what dot will use not paper weight

 

If you go by the rear tire rating as your limiting factor, you will be "safe" perhaps not legal by every single definition.

Pulling a larger bumper pull trailer instead of a gooseneck, just to stay under the GVWR is not a good idea. Gooseneck is much safer for heavier loads.

In terms of toolbox, it depends on the type of trailer and how much clearance you have. I had an over the rails toolbox and did not ever hit it. You will need to be more careful about your CAB especially since hitting the cab is going to cost more than any toolbox.

Your truck probably weighs about 7500, 4500 in the front and 3000 in the rear. Leaving about 3000 pounds of pin weight before reaching rear axle tire limits. In a 25% pin weight, this is going to be something like a 12,000 lbs trailer. You will be at or under both GAWRs but over your GVWR.

The rear GAWR is "set" by the lowest tire option available. Your axle is really a 10,000 lbs axle and the brakes are hardly different than a dually that has a rear GAWR of 9350 (!!!) lbs.

For example a 3rd gen had a rear GAWR of 6000 lbs and a GVWR of 9000 lbs. My 2nd gen has a GVWR of only 8800 lbs yet my rear GAWR is 6084 lbs. That's because a 245/75/16 is rated to 3042# each while a 245/70/17 is only rated to 3000 # each.

 

I agree with everything you said, but from a legal perspective, a 2500 SB truck can pull more bumper pull than gooseneck. The fact that you would be safer and under better control with a gooseneck does not matter (not from a legal perspective).

Can a truck rigging/work truck outfitting company legally rerate your truck? Who does it if they do? I'm mostly interested in Ohio & Virginia.

 

Only if your information is wrong. The math is simple. If the following data is known:than all axle weights can be calculated. If the 'paper weights' are wrong, it is because the above information is wrong.

Obviously the safest way is to measure all the axle weights. This is tough to do before the trailer is bought, so reasonable approximations based on the above data must be made!

 

I would be happy to email you a working version of my Microsoft Excel spreadsheet for Truck & Trailer weight loading calculatios. Just PM me with an email address and I will send you a copy along with Dodge's PDF on Trailer Towing that I used as the baseline to determine max weights. I will need to add some notes to it to make it more clear and sanitize it a bit so give me some time. If anyone else would like a copy just PM me and I will send a copy. Disclaimer: Use as a reference guideline only, my assumptions and formulas could contain errors! The only absolute way is to use a certified multi-axle scale.

 

Except for one pesky variable: How the truck and trailer is loaded by location. If we think of the GN as a teeter-totter with fulcrum point . (half way between tandem axles), lets say I place 1000 Lbs closest the fulcrum less weight is transfered to the GN coupler versus placing it nearer the coupler up front of the trailer. That is the variable that is the most elusive and the only accurate way I would know for sure would be to weigh it each time, after loading, on multi axle scale. We can get somewhat close by approximation but when you are getting near your truck maximum ratings this becomes more and more relevant. If you are pulling something like a fifth wheel TT and you load it pretty much the same each time there is less of a variable once weighed. However if you are loading a cargo trailer, horse trailer, flat-bed GN with varying load sizes and weights it comes into play when right at the maximums. Plus if you load the trailer wrong (too tail heavy) you can run the risk of creating handling problems and axle/tire problems (disproportionate axle weight bias).

So, I guess it all comes down to saying that you may or may not be legal each time you tow if nearing the maximums due to multiple variables. If you get scaled and you are over your trucks ratings, you are over. There would be no denying that!

 

You are correct - if your down to being within 1 lbs. of any of the ratings, then you won't be legal - loads shift, you eat a couple of extra burgers, etc.

Still trying to get an anser on if any work truck outfitter can rerate a truck if wheel, suspension, etc. mods are performed.

 

In terms of legal, what are you worried about: everyday driving, or getting into an accident and then having a lawsuit? Driving every day on the road, you are not going to get into any trouble. The DOT will go by tire ratings as a rule of thumb and occasionally they will check GAWRs. I haven't seen a law that says you aren't allowed to go over the GVWR.

Yes, a truck/body shop can re-rate your truck but most will not do it for liability reasons.