Safety Margin

[ttavasc]

Originally Posted by N2DFire

Hey Guys - thanks for the info so far.

ttavasc - you missed it - I had payload listed above, but it's 1650 lbs
Also to muddy the waters even more, they already allow for 300 lbs passenger weight before calculating the payload.

Right now I'm pulling all my numbers from here and the RAM Owners Site.

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

It is a Penstar V6 Crew Cab 5'7" Box 4x4 - Page 3, Second Block, Second Line

RAM Owners says max 7350, this says 7160 so I will verify / cross this to the door sticker.

And in a "previous life" in college I was an engineer (never got to drive the train though ) so I understand about the weights, balance, how additional trailer cargo (and location there-in) affect hitch weight & payload as well as tow weight.

Right after I posted here the other day, I found my new favorite trailer (yeah I know tomorrow I'll probably find another one lol)

The "book numbers" on it are:
7550 GVWR
5356 Dry
2194 CCC
554 Hitch

It is a Rear Bath floor plan so the kitchen is mid-ship and thus most of the "heavy" cargo (pots, pans, food) will be over top of or aft of the axles and affect mostly the Tow Weight. It's the front storage and hitch weight I'll have to watch but I'm not really looking to stuff a bunch of tables, chairs, crap, etc under there anyway.

And hopefully I'm not coming across as a know-it-all @$$hole in my response because that's 100% not where I'm coming from & I really do appreciate you guys time & advice.

Thanks Again guys!!

I am familiar with those charts from the RAM web site. I think you meant Page 4 and not Page 3 since you indicate you have a Crew Cab. If those are the numbers you are using instead of what is actually printed on your trucks door stickers then you won't have accurate payload figures. According to that same chart a Hemi-equipped Crew Cab 4x4 w/6.4 bed and 3.21 gears, which is what I had, shows payload of 1480. As I've stated, my actual payload was nowhere near that. If I had simply relied on this chart I would have set myself up to be significantly overloaded. Footnote # 1 on the chart states payload and max trailer weights are estimates. Other footnotes indicate how those estimates are arrived at including # 5 which alludes to how they are estimating those values based on available options.

If you want to know what your specific truck is capable of look at your drivers door Tire and Loading Information sticker for the phrase "The weight of all occupants and cargo should not exceed XXXX". That number is what you want to work with, or better yet, load up the truck with full fuel, all passengers and cargo you intend to carry when towing and run it over a CAT scale. Subtract that weight from the GVWR on the other driver door sticker. What remains is available payload for tongue weight and WDH.

When looking at trailers bear in mind that you will not be towing it empty other than to get it off the lot. Also, you won't find a trailer on the lot that weighs the brochure dry weight due to options added. You can look at the yellow loading sticker on the side of the trailer to see the as-delivered weight which usually includes full propane.

Use the GVWR of the trailer for estimating tongue weights. While the stated range for tongue weight is 10-15% of loaded trailer weight, most travel trailers do best in the 12-15% range. If you want to be conservative in your estimates use the worst case scenario of 15% of the trailer GVWR. Personally I use 13% as I feel that provides a sufficient amount of margin in most cases.

In any case, I don't think you'll find the towing experience of the Pentastar with a trailer likely approaching 7K loaded weight to be all that pleasant. I think somewhere in the 5-5.5K fully loaded range would be a much better fit. Good luck and safe travels once you hit the road!

[1bigmess]

Keep in mind that if you do too much to unload the hitch of weight so that you can tow a heavier trailer by loading the trailer with too much weight towards the rear of the trailer, you create a situation that can cause out of control trailer sway.
https://youtu.be/4jk9H5AB4lM

[Part-time]

My guide line is 60% of towing capacity of the truck. This will allow for plenty of power in reserve and more import is the reserve braking capability of the combination. Your driving experience will be much more pleasant too. Towing at capacity is riskier leading to more stress on the driver and the truck.

Just my thoughts

Tony

[1320Fastback]

Trying to stay around 5,000-5,600 Loaded will make towing somewhat relaxing and shouldn't be too hard on the truck.

[N2DFire]

Originally Posted by ttavasc

I am familiar with those charts from the RAM web site. I think you meant Page 4 and not Page 3 since you indicate you have a Crew Cab. If those are the numbers you are using instead of what is actually printed on your trucks door stickers then you won't have accurate payload figures.

You are correct on the page number. I copied / pasted from my post on another site and forgot to come back and correct it here.


Also - Payload on door sticker is 1405 lbs.

Originally Posted by ttavasc

When looking at trailers bear in mind that you will not be towing it empty other than to get it off the lot. Also, you won't find a trailer on the lot that weighs the brochure dry weight due to options added. You can look at the yellow loading sticker on the side of the trailer to see the as-delivered weight which usually includes full propane.

Understood and for anything I am looking at locally I am noting / recording the weight from that sticker. But I am also looking at TT's from as far as 4 states away so the "Book Weight" is all I have for a head to head comparison for now. I have generally allowed 300 - 400 more lbs for actual dry weight.


I'm going to contact the dealer of the unit I'm looking at and request the stickered dry weight this week.

Originally Posted by 1bigmess

Keep in mind that if you do too much to unload the hitch of weight so that you can tow a heavier trailer by loading the trailer with too much weight towards the rear of the trailer, you create a situation that can cause out of control trailer sway.
https://youtu.be/4jk9H5AB4lM

Yes sir - I am aware of the "Tail wagging the dog" when improperly loaded. Too much rear weight acts like a large pendulum and a smaller TV doesn't have the size / mass to counteract the induced torque moments once the weight is set in motion.


Thank you all once again. Your knowledge & experience are much appreciated.

[shane_the_ee]

Originally Posted by 1bigmess

Unless you... take no clothes with you on your trip.

Sounds like a fun trip, if you can avoid the sunburn!

[shane_the_ee]

Originally Posted by N2DFire

And in a "previous life" in college I was an engineer (never got to drive the train though ) so I understand about the weights, balance, how additional trailer cargo (and location there-in) affect hitch weight & payload as well as tow weight.

Uh-oh. Take a close look at my username. There's a huge difference between doing engineering math in college and doing it in the real world. In college, they give you number for this spec, another for that spec, you do some math and viola! here's the answer. In the real world, some product has a number for spec, so you do some math, put it in your product, take it into the lab and... it doesn't work! Then you realize that the spec was written assuming certain conditions and you didn't pay attention to those certain conditions*.


Your truck's manufacturer wants to advertise a really big number for the maximum towing spec. So they calculate it assuming something like a long flat bed trailer with a single layer perfectly positioned bricks on it and a horse jockey driving it (after removing everything that weighs down the truck, like whatever's in the glove box, the floor mats, etc)** Are you really going to go camping in a flatbed trailer with a load of bricks?



Meanwhile the trailer manufacturer wants to use the lightest possible weight in their brochure. So they remove everything they can (like propane tanks, batteries, etc). Sometimes they go one step further and and include a little asterisk and state "plus weight of options". And then you realize every trailer includes option packages, which include things like the awning and the spare tire and the rear bumper. Are you really going to remove all that stuff before you go camping?


The senior engineers get paid the big bucks because they can look at a spec sheet and know intuitively what assumptions were made and know how to adjust the numbers and what questions to go ask before deciding on that part.


The more experienced folks here are telling you to look for a trailer with a GVWR of 5000-5500lbs because they've learned how to take the marketing brochure towing spec and adjust it for how your truck will actually be loaded with people and stuff in the bed (firewood, tools, bikes, whatever). And they're telling you how to take a trailer "dry weight" and adjust it for how you'll end up loading it to take it camping.


The careful reader will note, that like all experienced engineers, they're giving you a weight number that's going to constrain other parameters, like how long of a trailer you can pull safely. That's not a number in your truck's towing guide spec, now is it? But it's important to your ability to tow something safely... Think about how big of a sailboat sail you could tow with a max towing a capacity of 6000lbs... think your truck would be able to keep it in your lane at 65mph with a 50mph cross wind?


*'cause they weren't printed in the spec because that drives away prospective customers, and now you're actually a paying customer who will pay big bucks to have them upgrade the part to suit your application... You had to be smart enough to ask more questions instead of just looking at the spec sheet. Like they quoted you some really fast processor speed but that speed requires cryogenic cooling. Your design did include cryogenic cooling, didn't it?



**And sometime's it's even worse than that. The max towing spec is for a stripped down, no options model of your truck. The one that comes with no heavy motors to move the windows up and down, adjust the seats, etc, etc.

[1bigmess]

Thanks Shane. From what he's written as responses, I'm not sure that some of the things we've all been saying have really been heard, like look at the GVWR and not the mfr advertised empty weights. I grew up with two engineers, and it's astonishing how a highly educated and experienced mind can overlook something because at that moment, it doesn't matter to the thinking being done, and after being ignored once it is further ignored until there is some kind of problem in the results, and sometimes even then the one little thing that was ignored at that moment a few minutes isn't recalled.

My experience with engineers is they often like to max out design capability in the search for the most bang for the buck, but in an RV, you want to avoid all banging at all costs. No banging!

Not knocking engineers, they are operating at a level way beyond my abilities, and I admire them, just an observation. I especially admire engineers that design new things to solve old problems that haven't been solved before. That is some very impressive mind stretching IMO.

You don't have to have the mind and experience of an engineer to buy and enjoy an RV, but ignoring all the very salient points being brought up could be risking the safety of yourself, your family, and others on the road. After all, the point is to enjoy this stuff when you're actually doing it, right?

[N2DFire]

Originally Posted by shane_the_ee

Uh-oh. Take a close look at my username. There's a huge difference between doing engineering math in college and doing it in the real world.

Shane, I am very much aware of what an EE is along with the differences in "Real World" vs "Book World" engineering. I have in fact passed a couple of engineering licensing / certification exams myself, I simply opted not to pursue engineering as a career hence the "back in college" remark.

I am also well aware of the tricks and gimmicks that both the auto and TT manufacturers use to manipulate the numbers. That's also why I hated "Statistics" back in college because you can make numbers say or mean anything you want depending on how you qualify & present them.

Originally Posted by 1bigmess

From what he's written as responses, I'm not sure that some of the things we've all been saying have really been heard

Quite the contrary good sir. Every piece of advice and knowledge shared has been noted. That's probably why I'm still shopping instead of camping in my backyard with a TT I can't pull anywhere.

My responses were/are a part of the discussion and learning process. If you will see, each time someone suggested looking at different numbers / values I did in fact go back & research said numbers and added them to the discussion.

Not once was I argumentative, dismissive, condescending, or otherwise rude to anyone offering advice & wisdom.

Once again I genuinely thank you both for your time and knowledge shared.

[1bigmess]

OK, cool, and I don't think that backyard camping isn't fun. I just now have a backyard in some really amazing places.

Good luck. I hope you find something you really enjoy for a very long time.