Math Formula for Weights

[JABURKHOLDER]

Originally Posted by R & S Woodie

Just had new 3931FB delivered Monday to a campsite in Arcadia, Florida. Now we have to get truck ordered. We see discussion on weights but we don't see how this formula works. How do we determine hitch weight?
Either the Diesel, 4x4, F3500 SRW or DRW can more than handle the 16,500 GVW of the fifth wheel but what is the formula to determine the hitch weight which will determine if we must go DRW? We had transport tow truck stop at the scale so we do have the weight of just the fifth wheel, plus a separate ticket with fifth wheel and transport truck. Would really appreciate the formula to figure this out. We are coming from a motor home so this is all new to us.
Thanks!!

This is the simplest answer I can think of for you...
Hitch weight should be 15 - 25% of the RV weight. Instead of trying to figure out the actual RV weight, just take the RV GVWR and multiply that by 25%. In your case that is 4125lbs. Just find a truck that has a cargo capacity and axle capacity greater than 4125lbs. The other thing I would do is add the GVWR of the RV to the GVWR of any potential truck and make sure the truck's GCWR is greater.

This is an example using my truck and RV:
RV GVWR = 16960lbs
Max pin weight - 25% of 16960 = 4240lbs
Truck cargo capacity = 6460lbs
Truck axle rating = 9650lbs
Max pin weight is well within the truck numbers

RV GVWR = 16960lbs
Truck GVWR = 14000lbs
16960 + 14000 = 30960lbs
Truck GCWR = 35000lbs
Max RV and truck weight is well within the truck GCWR

By doing this simple math, you will almost never have an underrated truck.

Hope this helps.

[vipermanden]

IMHO, I think a SRW or DRW will work to pull your 5th wheel, but I wanted the added safety of having the DRW in case a blow out in the rear. I would still have one tire to limp me to a tire place! As far as parking the DRW goes, sure it is a little bit of a challenge, but in the last 2.5 years we have been to 41 states and two provinces of Canada, and have been to over 80 RV parks, and we always found a place to park.

[agggitator]

When in doubt, get the dually......👍

[Mark N.]

For 6 years, I pulled a 3400RL with a Ram 3500 shorted. Not a single issue, problem or regret ever. No flippin' way I would try putting up with a dually in my life. I positively would downsize a trailer before putting up with that headache and cost of ownership.

[vipermanden]

It's all about safety, and if cost is not that big of a factor, go with the dually. If cost is a factor, then go with the SRW. It is totally up to you. None of us know your situation, so go with what you can afford.

[Eagleback]

Originally Posted by Mark N.

For 6 years, I pulled a 3400RL with a Ram 3500 shorted. Not a single issue, problem or regret ever. No flippin' way I would try putting up with a dually in my life. I positively would downsize a trailer before putting up with that headache and cost of ownership.

To each is own.

[sdetweil]

Originally Posted by knapper42

Now I'm confused. I have a 3560RL we bought last Jan in Quartzsite and have pulled it with our Ram 2500 diesel. The Cat scales shows my Ram weighs 8560, front 5120 - rear 3440, fully loaded includes BW hitch.
Hitched to Montana shows, front=4880, rear=6280, trailer=10820 making combined 21980.
The truck spec shows gcwr as 25K. so that seems ok
The Pin weight shows to be about 2980. so that's not good because the truck spec say payload is 2150. 830lbs over weight. right?
rear tire capacity is each tire 3560. capable of carrying the payload. also have air bags to take some strain off of the coil spring.

it looks like to me that the total weight are within spec but the payload is exceeded but yet the tires and axle are capable of carrying the weights.

Where the heck do I stand? sorry to be so dumb but after reading all these posts I concerned I'm not traveling safe.

state licensing regulations separate different classes of trucks, using 10,000 lbs as one limit. (over 10,000 is "obviously" 'commercial' in many states).. so truck manufacturers make a product that gets UP TO the 10,000 limit, but not over. 2500 for Ram/Chevy, 250 for Ford. doesn't matter whats UNDER the skin of the body.. the sticker wins.... (from the manufacturer)..

now.. CAN u exceed the limits of the sticker... sure.. is it safe? maybe, many say yes, many say no..

how do you do the math? take the max trailer weight and divide by 5.. that is the recommended pin weight... will the truck carry it according to the sticker?

I have a dually for this very reason.. I had a shortbed truck once, and it was a dream to park.. that is the ONLY thing I don't have now... walking doesn't hurt me..

[CaptnJohn]

Either should work fine. Two trucks back was a DRW Affectionately named Pia. Never again, I'd go to a popup 1st. JMO, but it really was a PIA in many ways. Current 5er has a 15,200 GVWR and is about 1000# on the nose under that when loaded for snowbird trips. My F350 SB SRW meets all the numbers with some to spare. That includes payload with separate washer dryer in the nose!

[laverdur]

I read a lot of the replies to this question and all seem to contain part of the truth. Your Monty has a sticker on the front street-side corner that gives GVWR, pin weight and max payload. There should also be a tag or sticker (maybe inside a cabinet door or on the entry door) that tells the dry weight the day the rig rolled off the factory floor. Dry weight does not include filled propane tanks, a battery or two, fluids in holding tanks or the fresh tank. Any dealer installed options must also be added to the factory rollout weight, with an attempt to apportion the added weight to the axles and kingpin according to placement within the rig. It's easy to look at truck brochures and get weights but that can be misleading. Trim levels and options can make the truck a lot heavier than what a brochure might state. The truck will have a sticker stating GVWR and axle weights. The weight of the king pin will be key to whether you stay within these limits. It is generally true that you want approximately 20% of the total 5er weight on the pin. Since it is possible for you to load the 5er to its max GVWR, 20% of that number is what I would work with for pin weight and select SRW or DRW based on that. Driving an overloaded truck is illegal, to say nothing of not being very much fun. If you are involved in an accident, you could be held liable based on being over weight alone, even if that was not a contributing factor. Always better safe than sorry.

[Beau2010]

We have been pulling with our 3500 dually for 2+ years from the Carolinas to California and will never go back to SRW. The very narrow streets in Charleston and New Orleans are certainly a challenge but that is why God made Uber and Lyft. Having pulled the same rig with both trucks, there is just no comparison. Sure, if you can’t handle the bigger wider truck, go back to your pop up. For us, the dually is the only way to go.

[laprezgpoc]

Originally Posted by R & S Woodie

Thank you all so much for the information. Very Helpful! Wanted to make sure we were accurately understanding this process.

Checking F3500, 4x4, 6.7 L Diesel, crew cab short bed, SRW brochure hitch weight of 3950 but door tag of new truck says only 3595. Monty brochure hitch weight for 3931FB says hitch weight of 2530 but a call to Keystone and the actual figure went up to 2610. All the figures are going the wrong way.

If truck hitch 3595 - 2 people/cargo 450 - 267lb hitch - 2610 Monty empty = 268 cargo. Not enough to even add generator let alone cargo.

We previously owned a DRW but did not pull RV with it (work vehicle). We did not want to do that again but we also will be doing a significant amount of traveling all across the country and don't want to be on the edge so may have to go DRW again.

I think you have answered your own question (and congrats to you for asking). A SRW will pull this Montana, but you will be at max capacity and maybe a 100 or 200 overwt. If you want that capacity cushion, then a DRW would be your choice. Again the SRW will do you fine, but the DRW gives that extra cushion (and as someone said "you don't have to worry about weights"). (And fyi,some of the DRWs on here probably should move to a med duty - as they are pushing the capability of the DRW - but it is all good....

[CaptnJohn]

Originally Posted by Beau2010

We have been pulling with our 3500 dually for 2+ years from the Carolinas to California and will never go back to SRW. The very narrow streets in Charleston and New Orleans are certainly a challenge but that is why God made Uber and Lyft. Having pulled the same rig with both trucks, there is just no comparison. Sure, if you can’t handle the bigger wider truck, go back to your pop up. For us, the dually is the only way to go.

I could handle the dually. It was just a bigger pia than a sane person without a need desired. At 43' and under 15,000# there is no need. Now if your ego requires it, enjoy.

[Cyride]

I purchased a new 2018 Ford diesel dually this summer as we are planning on purchasing a new 381TH. When I started to look at trucks to pull the weight of the 5th wheel I told myself in no way did I want a diesel or dually! However, the math just didn't work out to even consider going with a SRW truck. Much to my apprehension I ordered the new dually. I have to say it is a beautiful truck to drive! My fears of getting into and out of parking places and lots has been unfounded. My truck is a full crew cab with the 8 foot box and I am very happy with it. When Im in a tight spot the 5 cameras on board give me a top down view of the whole truck. Im not saying you'll get into every lot, heck there's one place in town I don't even like going into with my Outback! I can honesty tell you I in no way regret going with this big truck and as long as I have that type of load to pull I am very happy knowing I will be able to do so safely! Good luck on your purchase.

[dvines]

I had the same dilemma when I was shopping for a truck. Based on all my reading, it seems the two weights you NEVER want to exceed are the weight ratings on the tires and rear axle. Do the math, stay within those limitations and you will be fine. I actually went with a High Country because of the lower pin weights. After it was all said and done, I even had enough "spare" capacity to install a 46 gallon aux fuel tank.

[vipermanden]

The RAM 3500 SRW goes from 11,500 - 12,300 GVWR depending on which model you get, and the RAM 3500 DRW is 14,000. GAWR the max you can put on the rear axle is 7,000 pounds for the SRW and 9,750 for the DRW So if your base weight is around 3,000 pounds on the rear axle, it gives you 4,000 to work with. Put the hitch in the back, and passengers and dogs, etc., and that 4,000 comes down to 3,400? Your pin weight when fully loaded will approach this and possibly go over. Use this chart to see the numbers. This is for 2016 , my truck, but i am sure you can look up for 2019 also?

https://www.ramtrucks.com/assets/tow...ing_charts.pdf

[DmaxDually]

I'm going to be blunt....Get your self a diesel dually and don't look back. Everybody is always worried about towing weight and hitch weight and what the truck can pull.
Just as important, if not more, than what the truck can pull is what the truck can STOP. Yeah your truck might be able to tow it but can your truck stop it?
It's easy to start out slowly from a stop and get up to speed. You can take as long as you want and go as slow as you want.
Now just think about the other side of the coin. You're cruising down the highway at 60-65 mph pulling your 17,000+lb 5th wheel enjoying the ride. All of a sudden a 1/2 to 3/4 of a mile ahead something happens or someone does something stupid and cars start hitting their brakes and slowing down fast. That when stopping power comes to mind and it's too late..
My 2012 dually is designed to tow up to a 23,000 lb trailer but more important it is design to stop it too. It also has an exhaust brake. The newer duallys are design to tow even more 25 to 30,000 lbs. They put just as much thought if not more into stopping that weight as into towing it. The dual wheels in the back gives you more tire contact and make a big difference in stability and stopping.
It's not a good feeling when you realize you bought the wrong truck because your trailer pushing you down the highway when you are trying to stop in a hurry.
You spent a lot of money on that new camper. Don't try and save a few bucks on your safety by buying just enough truck to pull it. With the weight you are pulling get a dually and you won't have to worry about doing math when it comes to weight or trying stop it..
Oh yeah..congratulations on your new camper.

[CaptnJohn]

Ever hear "misery loves company "? That is what SOME dually owners have. If NEEDED get a dually,. Buy what you need.

[DmaxDually]

Originally Posted by CaptnJohn

Ever hear "misery loves company "? That is what SOME dually owners have. If NEEDED get a dually,. Buy what you need.

Yeah..that can be said about anything in life. I'm not one of the dually owners who has misery....I love my truck. It is my only vehicle and my daily driver. I am glad I bought it. As a matter of fact I bought my Dually before I even thought about buying a 5th wheel because I like the truck.
If we went through life just getting what we need.. life would be pretty boring.
Unless you're homeless everybody has a lot of things in their lives that they don't need..

[Eagleback]

Originally Posted by CaptnJohn

I could handle the dually. It was just a bigger pia than a sane person without a need desired. At 43' and under 15,000# there is no need. Now if your ego requires it, enjoy.

My DRW is a daily driver to work and play and no issues here. To each is own and i dont do it for my ego but for safety for my family and others on the road. But as stated before if you end up over weight and end up in an accident you will be held accountable and your insurance might not pay for negligence. but you will pay the hefty fines and possible court cost. Now Enjoy.

[LindaV]

Get the dually. We went the F350 but got the model with the higher GVW and we can pull and stop ours just fine..but we are right at the limit with payload. Even with distributing the weight so that some of the heavier items are behind the camper axle we are still at the limit. No leaway for getting a generator if we want one.
Get the dually.