Estimating Max weight allowable

[youracman]

Gents….. Sorry in advance for the lengthy post, but I want to make sure I have a basic understanding of weight considerations …. and if not, I know someone out there will educate me a bit.

I am needing a little guidance as I shop for a used 5th wheel. I want to stay with a ¾ ton, non-dually truck and I want to stay "legal" in regard to weights…..given our litigious society (+ I don't want to hurt anybody.) From reading (and trying to digest) the extensive info posted by owners on this forum, here's what I come up with to at least "ballpark" the heaviest 5er I can safely pull with a given truck: For example, I looked up the (generalized/literature) numbers for a 2012 Duramax HD Crewcab and they show a Max 5th Wheel Trailering Capacity of 17,800 lb and a Payload Capacity of 3670 lb (including a 150 lb driver ….. ahem) and not including passengers, hitch, accessories, etc.

So as I look at used units online, I am thinking that the weight listed is most often the one the factory publishes and I understand from the folks on this forum that they almost always weigh considerably more than that number (sometimes, an ad for a used unit will say "Scale Weight" but even then you don't know how it was loaded ….. propane-wise, canned goods wise, etc.)

SOoooo what I have done is to use the "listed" weight and add 3000 lb and "assume" that will probably be in the ballpark for the GVWR and I will plan to load things up to that GVW number before I "hit the road"……. just for estimating purposes. I then assume that the pin wt is 20% of that. Based on those assumptions then, I should probably not be looking at a 5er with a "listed" or "NADA" wt of over 11,000 lb. That is: 11,000 plus 3,000 would give me a wt to be towed of 14,000 (well under the 17,800 capability advertised for the Duramax HD ) but an estimated pin wt of 2800 lb! So I am pin wt limited; i.e., 3670 lb by the truck manufacturer and I only have 3670-2800 = 870 lb of CCC left for the people, hitch, etc in the truck.

I know I would need to have more data re the GCWR for the truck, the GVW for the trailer, etc but do I at least have the right approach as far as ruling out some units that appear to be too heavy for a ¾ ton HD? Or am I missing a key point?

Thanks for your patience, Ed S in Fairview,TX

[azdryheat]

Check the stickers for the UVW, which is what the trailer weighed leaving the factory. In lieu of that look for the max cargo weight and subtract that from the GVWR to get the UVW. For me I just go by the trailer's GVWR and my trucks 5th wheel capacity. If the numbers are close then I'm good to go. Since I am not commerial, no one cares what my rig weighs. In my case my truck is rated for a 13,900 5th wheel and my Everest has 14,000 GVWR. We don't carry tons of stuff and our tanks are empty. Close enough and it tows wonderfully.

[azdryheat]

One other thing. I upgraded the truck shocks and added airbags. Makes all the difference when towing.

[TexasTwoStep]

You can also find the rear axle capacity on the front door edge on the driver's side in a GM. I think that capacity is around 6,200lbs for a 3/4 ton newer truck which includes truck weight on the rear axle.

[TXiceman]

If you will also note in the small print for the towing capacity of 17,800#, it will have a statement with something like, you are not to exceed any of the manufactures ratings such as GVWR, GAWR and GCWR. The GCWR is not a problem with a 3/4 ton truck. The problem will be GAWR and GVWR for the truck.

A typical 5er will have a loaded pin weight of about 20% of the trailers GVWR. So if you take a 5er weighting 17,000#, you can expect a pin weight of about 3400#. You already see that the trucks MAXIMUM is 3670# which includes a 150# driver. This is based on a stripped base model truck, no cargo, no accessories, no passengers and no hitch. So you real world payload is probably something like 3000# (or less) when the truck is wet and loaded.

The best thing to do is to fuel the truck, load up the passengers, too box etc and get the weights on the truck. Add 150# for the 5er hitch if you do not have one yet.

Now in the owners manual you will find a GCWR for your specific cab, engine and axle combination. On the drivers door jamb, there is a sticker with the GVWR and axle GAWR.

GCWR - loaded truck = Maximum loaded trailer weight.

GVWR - loaded truck = Max loaded trailer pin weight.

This way is pretty fool proof and will keep you within manufacturers ratings.

Ken

[tuffr2]

You are correct - it is the pin weight (what the truck can carry) that is the 1st limit you will reach.

I am not sure why manufacturers say that the truck can tow 18,000lbs when it can't carry 20% of that weight. Maybe horse trailers have a much lighter pin weight. I bet that is it !!! Those darn horse trailers.

[CD]

A few years ago I hauled a tractor home with my 1T dually. The tractor & trailer wighted 17K. I am here to tell you I would not haul that much very far or often. Just too much weight for good handling. The bigest concern was stopping.

[JIMNLIN]

I am needing a little guidance as I shop for a used 5th wheel. I want to stay with a ¾ ton, non-dually truck and I want to stay "legal" in regard to weights…..given our litigious society

First off legal weight issues for your private use truck revolve around proper registered weight (if any) as some states have that requirement. My state as others have no weight registration for a private owned vehicle (non commercial).

And staying within the trucks GAWRs/tire capacities. And no this isn't a commercially registered vehicle.
GVWR isn't used for how much load the truck can carry.
GCWR isn't used in any legal sense as it isn't on the trucks cert placard nor is it a fed requirement.

Looking at GM online specs sheets shows the 2500 crew cab long bed D/max has a 24500 GCWR. GVWR is 10000 lbs with 6200 RAWR.

SOoooo what I have done is to use the "listed" weight and add 3000 lb and "assume" that will probably be in the ballpark for the GVWR and I will plan to load things up to that GVW number before I "hit the road"……. just for estimating purposes. I then assume that the pin wt is 20% of that. Based on those assumptions then, I should probably not be looking at a 5er with a "listed" or "NADA" wt of over 11,000 lb. That is: 11,000 plus 3,000 would give me a wt to be towed of 14,000 (well under the 17,800 capability advertised for the Duramax HD ) but an estimated pin wt of 2800 lb! So I am pin wt limited; i.e., 3670 lb by the truck manufacturer and I only have 3670-2800 = 870 lb of CCC left for the people, hitch, etc in the truck.

IMO you have a good plan looking at 14k trailers and under. A 17k RV 5th wheel trailer will have too much pin weight on the trucks rear axle/tires. I would keep a wet pin weight under 2600-2700 lbs. Use GM weight calculator for figuring the trucks actual weights with all packages and options. Model Information - Online Ordering Guide

Keep in mind these trucks aren't made just to pull a RV on occasion. The majority with the same truck are working for a living.
Many are pulling a 17K GN flatbed trailer that can be loaded so the pin weight doesn't exceed the trucks rear axle/tires. We can't do that with a RV.

Also the only difference in the 2500 vs 3500 SRW truck is higher rated tires/wheels and rear spring pack. The rest of the truck is the same as.

[Franka548]

youtacman,
You are on the right track, use the GVW of the trailer and then 20% of that for the pin weight. To use my truck as an example, I have an 03 cclb dually, gvw of 11,400#, and my 5er GVW is 16,400#, front axle scales 4400#, rear axle scales 6600# and trailer axles scales 12,500# with a GCWR of 23,500#. So looking at 14,000# GVW max trailers should keep you pretty close on your weights.
My weights are with 2 people, full truck fuel, 1/2 aux fuel and 1/3 tank water.
Frank

[wingnut60]

Franka548,
Your rear axle scales 6600lb with the trailer on the truck?
Joe

[RustyJC]

Ram states the following in their bodybuilder's guide (the Gospel for truck and towing ratings):

Additionally, GVWRs and GAWRs should never be exceeded.

I'm sure Ford and Chevy/GM have similar language in theirs.

It's up to you whether or not you choose to purchase a tow vehicle with the knowledge that you're going to be exceeding one or more of the truck's ratings from the git-go. As an engineer, I wouldn't - if I'm buying a truck, I'll buy one that's rated for the job at hand. But, at the end of the day, it's your money and your choice.

By the way, Txiceman's post is an excellent, relatively simple method to size a tow vehicle or RV when you're in the shopping phase.

Rusty

[youracman]

Thanks for all the responses. Since I have bought neither the truck nor the fifth wheel yet I am most appreciative and I will now be a lot better-informed buyer. The "Online Ordering Guide" that Jim n Lin posted is a super reference: I had Googled up a lot of "stuff" but never saw that guide.

I have been lurking for a couple of months now (mostly at PPL's site there in Houston/New Braunfels.) Once I get close to "pulling the trigger" I will (hopefully) be able to get the GVW from the sales folks there (or from an owner) and if it looks doable (with some safety margin) I can drive down and look ..... especially at the roof.

BTW-I don't know how the Country Coach thing got on my profile ..... I musta messed that up at registration.....can't figure out how to fix it. The only RV I have ever owned was a little 20ft Terry "stick trailer" back in the 60's.... and it was a blast.

Be keerful out there.

[RustyJC]

The trailer's GVWR along with its GAWRs will be on a tag normally located at the right (road side) front of the trailer.

Rusty

[Franka548]

wingnut60,
yes 6600# on the rear axle with the trailer hooked up and about 30 gal of fuel in the auxilary fuel tank in the bed.
Frank