By Ross Regis
You will almost never tow what you think you can. To those of you who have owned RVs for years, this isn’t breaking news. Some of you follow the 80% Rule of Thumb: Your “real-life” towing capacity is around 80% of the advertised maximum. But is that margin even sufficient?
Let’s get into the nitty-gritty. And if you remember nothing else, remember this: Payload capacity, not towing capacity, is the real limitation of your tow vehicle!
Getting an answer about towing capacity is really, really hard!
I’m an RV design engineer. That’s right—I design some of the RVs you all are towing right now! And while I love this industry, I agree with the thousands of customers who demand better service, better construction, and better quality control. And nowhere is that information gap more excruciating than when answering the question, “How much can I actually tow?”
In recent years, the National Highway Traffic Safety Administration (NHTSA) has revised several labeling requirements to make towing and cargo capacities less opaque. But most customers still have trouble swallowing the alphabet soup—and RV salespeople aren’t exactly handing out calculators!
So I’ll say it again:
Payload capacity and hitch weight—not advertised towing capacity—will usually limit what you can tow.
- The cargo you add to your tow vehicle will drastically reduce what you can tow. In fact, with a full family and suitcases, you might not be able to tow anything!
- Real-life tongue weights can easily slash your towing capacity by 20-50% compared to the advertised maximum.
It’s bad news, I know. And while the 80% margin rule is useful, it’s still woefully inadequate. But I’d rather you find out now than $50,000 later.
Can you even trust advertised towing capacities?
The advertised towing capacities of most consumer pickup trucks are governed by the SAE J2807 standard—
Hey, don’t doze off! Get back here!
Motor Trend shows how the SAE J2807 is actually a pretty amazing test. The Highway Gradeability test takes place on the 11.4-mile Davis Dam road, a nasty hill climb in the Arizona sandstone desert, where the outside temperature must be 100 degrees minimum. It’s literally hell on wheels. I have a hard copy at my desk, so I can promise you it’s serious business!
So towing capacities are (mostly) standardized across manufacturers. Vehicles must survive several eye-popping strength and endurance tests. So that’s the good news. You can reasonably trust that you’re comparing apples to apples, Ford to Chevy.
But … can that Ford F-250 really tow 20,000 lbs.? Like, really?
When it comes to towing, the devil’s in the details
Auto manufacturers have dreams about the coveted status of “best towing capacity in class!” They’ll squeeze every pound possible out of their pickups (and their brochures). Their job depends on it.
So yes, some half-ton pickup trucks can tow 13,000 lbs.—with the right engine, axle ratio, bed length, cab style, hitch, tires, towing package, tongue weight, and a full harvest moon.
That’s a lot of assumptions. Here are some of the calculation assumptions typically made. (Check your manufacturer’s Towing & Trailering guide for the most up-to-date information.)
- Tow vehicle includes a 150-lb. driver and a 150-lb. passenger. (I don’t know about you, but I haven’t been 150 pounds since I was 16!)
- Tow vehicle includes the factory-installed heavy-duty towing package.
- No driving at high altitudes.
- No cargo besides operating fluids.
- No dealer-installed options or accessories.
- RV is towed with a weight-distribution hitch, not a weight-carrying hitch.
- RV has minimum allowable tongue weight (usually 10% for travel trailer or 15% for 5th wheel).
If any of those are not true … then you won’t be able to tow the maximum towing capacity. And in all my life, I’ve never met anyone who towed with a perfectly balanced hitch, no kids, no cargo, and no accessories! What a boring vacation that would be!
Let’s see how these real-life constraints change the maximum towing capacity for an RV.
P.S. You can find your advertised towing capacity on a Trailering Guide or Towing Selector chart from your manufacturer. You can also subtract your tow vehicle’s GVWR from its GCWR, both of which you can find on your Safety Compliance Certification Label.
What difference will just one pound of cargo make?
Adding cargo to your tow vehicle will multiplicatively reduce its towing capacity.
^That’s a super important sentence, so I recommend you read it again. You may not think that 90 pounds of cargo is a big deal. I mean, that’s just a large dog, right?
Let’s see what happens if you bring Fido along.
If your advertised maximum conventional towing capacity is 13,000 lbs., then I’d wager my retirement account (not worth much these days) that the auto manufacturer is assuming 10% tongue weight and a weight-distribution hitch.
If Fido is sitting in the middle rear seat, let’s assume half his weight (45 lbs.) is on the rear axle.
Now, the physics of weight-distribution hitches (WDH) can get complicated, so we’ll skip the algebra. But if your WDH is set up with ~66% FALR (front axle load restoration), then roughly 1 lb. gained on the rear axle = 12 lbs. loss of towing capacity. (That’s a super rough estimate, but it makes the numbers easy.)
Translation: If we assume half the cargo weight is on the rear axle, then every 1 lb. of cargo = 6 lbs. loss of towing capacity. At a certain threshold, it shuts down towing capacity completely.
So 90-lb. Fido just removed 540 lbs. of towing capacity. (Bad dog!)
And once you add your two 50-lb. suitcases and another 100 lbs. of emergency tools, snacks, drinks, and fishing gear, you’ve lost another 1,200 lbs.! Oof.
Note that you’re still well underneath your GCWR. But that doesn’t matter. You can’t overload your tow vehicle’s rear axle—and that’s what usually gives way first with heavy towable campers!
What difference will just 1% of tongue weight make?
Again, I’ll eat my hat if the auto manufacturer isn’t assuming 10% tongue weight for travel trailers (or 15% for 5th wheels). So a “13,000-lb. towing capacity” is just another way of saying a 1,300-lb. maximum hitch weight.
So, what if your travel trailer actually has a 13.5% tongue weight? (Which is a very reasonable number within the usual 10-15% range).
Turns out, that’s an extra 455 lbs. on the hitch. Not good. And because tongue weight multiplies weight on the rear axle, you’ve probably overloaded your rear axle by even more, up to 500-700 lbs.
Yikes. So with a 13,000-lb. trailer, you’ve way, way overloaded your rear axle and tires. You’re risking tire blowouts and permanent suspension damage.
Once you crunch the numbers … with a 13.5% tongue weight, you could only tow 9,630 lbs., tops. Not 13,000. That’s 3,370 lbs. less than you thought!
(And we haven’t even added Fido yet.)
This is also why very few half-ton pickup trucks can reasonably tow a 5th wheel camper. The pin weight is just too much for the rear axle, especially once you climb above 15%!
So what’s a math-averse RV owner to do about towing capacity for RVs?
Hey, it’s not all bad news! You have options.
- Weigh your RV. You don’t have to crunch numbers. You can take your RV to a scale and have all your axles weighed. Then adjust payload from there.
- Use a calculator. Check out this Travel Trailer Towing Calculator or this 5th Wheel Towing Calculator. While no calculator is 100% accurate, they can point you in the right direction.
- Research before you buy. I’ve talked with a lot of RV owners who discovered too late that they couldn’t realistically tow their new $75,000 RV. They either had to buy a new $50,000 truck or sit on a $75,000 white elephant. Researching tongue weights, pin weights, and payload capacities should be de rigueur for any RV purchase!
- Go smaller. I know it’s anti-American, but smaller RVs are the future. You can venture off the pavement, store them in your backyard, and tow them with half-ton trucks. Better to keep your tow vehicle big and your camper small.
I should answer one last question: Is the 80% Towing Margin rule safe?
Eh … it’s inaccurate. For big families and packrats, a 60-70% margin is more practical. But as I warned earlier, if you load up a Chevy Suburban with seven husky people and seven suitcases, you’ll probably max out the GVWR—and you won’t be approved to tow a single pound!
RELATED
- How do we educate the RV consumer about towing capacity?
- RV engineer spills the dirty truth about RV cargo capacity
##RVDT2238
To RV manufacturers, dealers and auto/truck manufacturers-“Liar, Liar, Pants on fire”. To any RV owner- including MH owners- They all don’t tell the TRUTH.
We turned down a beautiful Class C because it’s load capacity was 700 pounds. 400 pounds of humans, 70 pounds of pets leaves very little additional cargo.
When researching, be very careful about what they tell you on their web sites. My example: I bought a 2023 Tacoma TRD Sport with a tonneau cover, and a 2023 Freedom Express 20SE trailer (dry weight 4160 lb, gross weight 6000 lb). The web site said the truck could carry 1105 lb cargo, so I was good, right?
When delivered, the sticker on the truck said 940 lb cargo weight max – and that didn’t include the 65 lb tonneau cover. Then, the trailer was very hitch-heavy. The net result was that, while I didn’t violate my axle weights, my truck was right at GVWR! We had to do all sorts of gymnastics to get 100 lb under GVWR.
Checked out this trailer, looks great! This is the max (6000lb.) that I’d tow with my Silverado. I’m rated at 9300lb. tow with 2005lb. cargo cap.
Neither salesmen were any help to you, not right. Be safe!
Good article. Head spinning, yes. But still good.
When we start out on our semi-annual major trip, I have a rough idea of our cargo weight inside our car (Subaru Ascent). I also weigh the 21′ TT’s hitch (you can purchase a small crane scale along with making a sturdy wood frame for far less money than a tongue scale). The two weights have to be less than the rated tongue weight for our car.
It isn’t as good as a truck scale, but I can do this before leaving home and the nearest truck scale (a garbage transfer station) is over 20 miles away. That’s roughly 40 miles potentially overweight and an hour round trip travel to fix the issue.
Very well written and informative article! I wish everyone that towed would abide by the rules.
Who tows any trailer with more than one axel without a load distribution hitch? I have seen it done, but that’s just plain stupid. On that note I firmly believe that if you have good trailer brakes and good load distribution and you don’t drive like a maniac you can easily go over the max tow, and I would wager that a large portion of rigs on the road are well over max.
I have a large gas class A that we lived in for 3.5 years. It has around a 4600 payload and a 7 or 8k towing capacity. I never weighed it, but when I moved all our stuff out I was amazed at how much crap we had accumulated and was pretty sure we were WAY over our max weights.
Would have to respectfully disagree, Troy. Engineers use a margin of safety in life-safety applications for a reason. Towing accidents kill people; brushing off the importance of staying within weight ratings could be putting other people’s lives at risk.
I have a 2015 3 wheel Spyder they say 40 lb’s of tongue weight. after I bought it I towed it home with my car. I checked the tongue weight at home & it was 112 lb’s. how can I shift this weight off the tongue?
Either 1. – buy a weight distributing hitch. and/or 2. Move the load in your TT from the front to the rear
I sure wouldn’t want anything close to my 5,000 pound rating. I don’t mind shifting down on hills, but too much would worry me. Any direction I go has mountains.
I tell people whats your gvw ratio and go half that. Otherwise you will blow the engine and trans if nothing else.
I cannot believe how many times I have read or actually heard in person “Our vehicle can tow X amount of pounds and the dealer said we can tow this trailer (X minus 300 pounds)”. I was at Camping World for a warranty repair and got to witness an 8000 lbs dry weight trailer SOLD to a early 2000s Ford Expedition that had a tow limit of 8500 lbs. The top of the back tires of the Ford were into the wheel wells. The front tires had about a foot from the top of the tread to the bottom of the wheel well. Oh and they have a couple of teenage kids and a dog that will travel with them in the Ford. I laid into the salesman and he completely blew it off and quoted the tow capacity. Total idiot!
Is it the salesman or the purchaser’s fault? The person to blame is usually the person you see in the mirror.
Maybe there should be more emphasis on stopping ability rather than how much you can tow. I never worry about how much I’m towing. I worry about my ability to stop in an emergency situation that pops up unexpectedly. I pride myself on preventing these things but you just never know (which is why I upgraded from drum brakes to disc brakes).
Drive a school bus for a year. I have. 16 years and 2 as a tour bus driver. That will give you a great indication of how much stopping you really have. A football field? O yeah. Plenty of room.
IF the trailer has properly functioning brakes and IF the brake controller is set properly, the vehicle towing the rated load will be fine. Unfortunately many people on the road don’t know how to properly set the brake controller.
An excellent and very useful article, Ross. Thank you.
Last fall my wife and I were researching higher end 5vers (heavier) in the 34′ range. Pin weights were up there pretty close to what a lot of one-ton trucks are rated for…and that’s before the optional washer/dryer is installed WAY up in the nose adding hundreds more pounds on the rear axle!
Now imagine that scenario with the massive 40′ toy haulers so common nowadays…sometimes pulled by 3/4 ton trucks! Way, way overloaded.
The result is the overturned RVs we see destroyed in the ditches every year in our travels. Any little thing like a big wind gust or a blowout has magnified consequences when overloaded.
I know of one RV buyer who purchased a horse trailer 5th wheel with a 37% pin weight – straight from the upfitter! Boggled my mind.
I weigh my 22’ cargo trailer at a nearby moving & storage place. Their scale is paved all around so I can get tongue weight, total, and left/right if I want, and move things & re-weigh if needed. For $20 it’s nice to get real numbers and eliminate the guessing, no more worrying while driving.
My favorite saying goes
“ it’s not what they tell you but what they don’t tell that’s important “
This is a much better article explaining the limitations faced with towing your camper and the vehicle limitations. Thank you for a more pedestrian explanation of the numbers
Thank you! Glad I could help break down the numbers.
Really good, well written article, with lots of understandable information. Thank you !
The dealer WILL tell you your tow vehicle is fine. He wants to make a sale.
I had a bunch tell me that a 2500 would pull this 34″ 5th “just fine”.
Yes, but for how long?
Towing (Pulling) your trailer is the easy part.
It’s that Stopping, Steering and Control part that becomes a BIG PROBLEM quickly!
That’s another assumption behind the towing calculations; it’s generally assumed that a large trailer will be equipped with brakes responsible for stopping its own weight. In reality, this partially depends on the type and programming of the brake controller.
Fascinating and scary article! My question goes the other way, however. Specifically, we are flat-towing our Jeep behind a 38-foot gas motorhome. How do we go about calculating our cargo capacity (assuming that this would be more a limit than hitch capacity for towing a toad)?
Good information. We have used Changing Gears calculators for years – great resource for any questions about towing, buying or operating an RV.
This all reminds me of the day we picked up our first travel trailer from the dealer (previously had a pop-up camper) . We were getting the WDH adjusted and watching a new fifth wheel being hooked up to the buyer’s truck. We could only watch as the Ram 1500 left with it’s rear bumper dragging the ground as it pulled out of the drive with the grossly overweight fifth wheel weighing it down. We were shocked. The installer just said he sees it every day. Should be mandatory classes for new buyers before they make those uneducated decisions.
Sounds dangerous for the drivers and anyone on the road around them!
This article primarily covers travel trailers. Can we get another article from this RV Engineer that addresses the same issue with a 5th wheel? I’m interested to know how to apply the loss in towing capacity based on tow vehicle load capacity applies in the situation where no WDH is present.
Agree. I almost wish there was a service that would do accurate calculations for us “dummies” and I’d even be willing to pay someone who has these skills to do it. If anything just for knowing how “bad” I am 😉
For a 5th you want to be around 20% of the GVW at the tongue. Most people look at the dry weight and that’s bad. Go by max GVW of the trailer. This way you know for sure if you load it up, you’re covered at max tongue. If you have a 12k lbs trailer, tongue weight should be around 2400 lbs of tongue. Toy haulers be even heavier because they are designed to be balanced out with weight in the very back. Then add that, your hitch, you, your passengers, and any cargo in the tow vehicle. That’s your payload. You certainly don’t want that to exceed payload rating if the tow vehicle. Another consideration is rear axle rating. You certainly don’t want to overload the axle.
Great idea! Maybe I will. The math is actually friendlier. Because the weight of a 5th wheel is directly above the rear axle, there’s no need for extra weight distribution, and there’s less chance of the tail wagging the dog, so to speak. 1 lb of pin weight = 1 lb on the rear axle (mostly). Most of the time, the tow vehicle’s total payload capacity or RGAWR will be your two biggest limiting factors, though.
Ross – Well if you do, please assume the 5th wheel hitch base is mounted not directly over the rear axle but slightly forward of the rear axle’s centerline. Mine is and I suspect most are for the sake of sharing some portion of the 5th wheel’s tongue weight with the TV’s front axle. Thank you.
I know the jeep is 6500 gvw. The 21 foot trailer is around 3500 loaded and according to the mfg it says 3000. So there in lies that no I do not over load my trailer, pack what I need and go from there. Sad to say, I have three dogs, no children to go with me and a husband who would rather eat dirt then go camping at this late stage in the game. Since I pack only what I can mix and match I keep the towing capacity at a very lite weight. As for my weight well lets say its petite. As for Wolf Pass? Uh lets just say I missed the turn off. Too late. I use it for traveling to off winter sites and if I do not eat out pack food for what I can make quickly. Happy Trails.
I bumper pull a TH, because there wasn’t a 5ver that didn’t overload my back axle on my 3500 SRW. Great article, will save it to share.
Thank you!
Nice article. The thing I comment about most to new camper or prospective owners is to try and determine what’s the dry weight vs what I call curb weight? The factory markets dry weight to suggest it can be towed with a lightweight vehicle. In most instances, curb weight or what the camper weighs parked at my curb can be quite a bit different than dry weight. Add in propane, awning, spare tire, batteries, etc. Adds up pretty quickly. My preferred recommendation is to identify Gross Combined Weight of your tow vehicle to include Tow vehicle, cargo including passengers, camper and any cargo you’ve added to the camper.
What muddies the waters is that most people are accustomed to automotive terms like “curb weight” and “dry weight,” which don’t have a 1:1 equivalent in the RV space. The weight to trust isn’t the weight on the RV manufacturer’s website; it’s the weight on the sticker of YOUR RV. By law, that should be accurate to within 1.5% or 100 lbs., whichever is less.
That’s why I went Ram 3500 dually.
I cringe when I see what some people carry around with them. Full sized, wooden front porch, concrete buckets as weights, tents/chairs/firepits etc….
I weighed our 5th wheel first outing, and we were just about 100 lbs under. And we hadn’t even loaded all the extra goodies yet! Just mostly basics.
Good article. But there is another factor that is not mentioned: **Wheelbase of the TV**
There are many vehicles out there that have powerful engines and impressive tow capacities touted by their manufacturers. Especially SUVs. However, many are also short wheel base vehicles. Well, if you plan to tow a “lightweight” but long travel trailer with such a vehicle, you can count on white knuckles (or worse) whenever there is a crosswind or when a large vehicle like a semi truck passes you. Why? Because the trailer- not the tow vehicle- becomes THE BOSS. You can reduce this problem with an expensive hitch like a Hensley Arrow or a ProPride. I know this because I had this exact experience
Love this advice! Yes, luxury SUVs in particular seem to be at risk of towing trailers which are simply too LARGE for them, regardless of their weight. Becomes a case of the tail wagging the dog.
I think every individual that comes anywhere close to selling RVs should be forced to memorize this article. What a very well written, clear and accurate telling of the facts about this lifesaving aspect of the adventure we all participate in.
it was only after I left the dealership that I worked at selling RVs that I learned more about towing and weights and the information detailed here. There just is no concerted effort to distribute this information within the industry so I hope anyone who reads this does their best to get this information out there.
My trailer is a relatively small (5,300 pounds UVW) trailer and, after having it scaled, I upgraded my truck to a Ram 2500.
Hi, Tony. Dave Solberg has a two-part article on towing starting tomorrow. I haven’t read it yet, but at a glance it looks pretty thorough and informative. Have a good evening/night. 😀 –Diane
Great article, but I’m missing something. The article explains that there is a 1 to 6 ratio added cargo to a ~6 # reduction of towing capacity. Example, adding 1 # of cargo reduces tow capacity by 6 #’s according to the article. When entering real world numbers on the calculator, the tow capacity is reduced by a 1 to 1 ratio. Example, a 10 # addition of cargo reduces the towing capacity by 10#’s. My truck is a ’18 F150 super cab, 5.0L. Please explain. Also, If possible, please send formulas and calculations. I have no problem following them. Thanks.
Barry, the 1-to-6 ratio is a rough rule of thumb with some boundary conditions. It’s all about perspective. Yes, adding cargo to your tow vehicle reduces towing capacity at a 1:1 ratio if your GCVWR is the limiting factor. But what I’m arguing is that in reality, the way most people travel, you’ll overload your tow vehicle’s RGAWR before you overload anything else. If we make some weight distribution assumptions, such as ~66% FALR of the weight-distribution hitch and a central location of the payload between the axles, then that’s where the 1:6 ratio comes from. Again, it’s not a law, just a Rule of Thumb based on the way many people load their tow vehicles before traveling.