RVTC Towing Capacity Frequently Asked Questions (FAQs)

Since the debut of RV Tow Check, I have been monitoring what others have been saying and replying to several emailed questions. Here are some answers and explanations to typical questions concerning the towing capacity calculator.

The safest and most recommended answer is to ensure the max towing weight you chose by selecting a trailer with a GVWR equal to or less than the tow vehicle’s max towing weight.

However, suppose one is very meticulous with controlling the amount of cargo placed in a trailer. In that case, it is feasible to buy a slightly larger trailer, one that is more suitable for family needs. Routine weighing of the rig is necessary to ensure weight safety ratings are not exceeded. For more info on weighing your RV rig, visit FifthWheelStreet.com and follow the 4-Step Weight Safety Plan.

After entering all the required weight entries, the last page or section you will read is the Max 5th Wheel Towing and Max Conventional Towing weight results. The results is the maximum trailer weight (the trailer GVWR) the tow vehicle can pull without exceeding the vehicle’s weight safety ratings. The max towing weight results in these boxes may change when selecting various pin or tongue weight percentages.

RV Tow Check is about knowing the automobile’s realistic vehicle towing capacity before you go shopping for an RV. After deciding what is a max safe towing weight, then one knows the max trailer GVWR they need to look for. Entering trailer weight is moot.  

As far as the rear axle weight, I know some believe that is all one needs to be concerned with. Early in my calculator development, I, too, considered the rear axle rating important. However, over time, my impression changed. As a result, the GVWR will be exceeded 99.9% of the time before the combined GAWRs.

The SAE J2807 has three different formula sets. One for GCWR, GVWR, and rear GAWR. I have worked out a variety of scenarios with all the formulas. However, every time, the GVWR formula would calculate towing capacity less than the rear GAWR formula. Therefore, I decided that using the rear GAWR has little value and is more likely to cause one to exceed the GVWR.

The best way to answer this question is to use a real example from a client.

Q: "The RV Tow Check states that my 2015 Silverado 2500 with Duramax, CC, LB, 2WD, can only tow 11,250 lbs @20% pin weight with a 5th wheel. The dealer told me I could tow 17,300 pounds. Is the dealer wrong?" The weights are: GCWR: 24,500, GVWR: 10,000, GVW: 7,750 (includes two people, cargo and hitch). The scaled axle weights without the trailer attached are—front: 4,750 and rear: 3,000.

A: The RV Tow Check (RVTC) calculator computes tow capacity based on available payload—a part of the gross vehicle weight rating (GVWR), the gross vehicle weight (GVW) of the vehicle to avoid exceeding the gross combination weight rating (GCWR), and the trailer weight rating (TWR). All vehicle manufacturers use words like "never" or "must not" about exceeding these ratings: GCWR, GVWR, GAWR, and TWR. As revealed below, you will learn that GVW plays a very significant factor in actual towing capacity.

The following shows you how RV Tow Check calculates for fifth wheel towing only.

Method 1—Available payload formula: GVWR-GVW-(unscaled equipment, cargo, driver and passenger weight)=Available payload.

Your truck's available payload is 2,250 pounds. RV Tow Check uses the available payload and applies the SAE J2807 methodology to calculate the realistic vehicle towing capacity. Per SAE J2807 specifications, vehicle manufacturers use 15% to calculate the vehicle TWR, and it is primarily for 5th wheel and gooseneck trailers. RV Tow Check allows you to view the towing capacity for a full range of recommended percentages (10%-15% for conventional trailers and 15%-25% for fifth wheel and gooseneck trailers).

Method 2—The standard GCWR formula: GCWR-GVW-(unscaled equipment, cargo, driver, and passenger weight)=Towing Capacity

Dealers commonly use this method, and it should only be used for conventional towing. Often, the towing capacity is limited by the conventional hitch rating.

With this standard formula, your truck's tow capacity is 16,750 pounds.

Method 3—Trailer weight ratings (TWR): Some manufacturers derate the towing capacity below methods 1 and 2 described above to ensure the rear GAWR will not be exceeded or for other reasons, such as OEM hitch ratings. Therefore, this rating is critical to consider as it should not be exceeded. For your truck, the 5th wheel TWR is 17,300 pounds.

Decision time—RV Tow Check throws out the highest towing capacities from the four calculation formulas. In this case, method 2 is discarded because it would cause the GVWR to be exceeded, and Method 3 is higher than method 1. Method 2 will be used only when the towing capacity is limited by the GCWR or the available payload is very high. The high available payload is typical with some one-ton dually trucks, yet method 2 may exceed the TWR.

Percentage selections—After the initial max towing capacity appears, you may instantly view different max towing capacities by selecting any of the available kingpin or tongue weight percentage buttons for the two trailer classifications. When choosing the pin weight percentage that you feel is safe for your towing situation, it is your decision. The safest selection will always be the highest percentage.

Typical GCWR formula—When towing capacity is calculated with the standard GCWR formula that has been used for years, the results will reveal that your truck could tow 17,300 pounds as you stated (GCWR-curb weight=Towing Capacity). Notice that this GCWR formula does not include optional equipment, passengers, a fifth wheel hitch, or any other cargo you may carry in your truck. The potential PW @20% for a fifth wheel weighing 17,300 pounds would be 3,460 pounds. Add the likely PW to the scaled rear axle weight (3,000), then your rear gross axle weight (GAW) adds up to 6,460 pounds.

Here is the problem with the typical formula—When adding the potential rear axle weight (6,460) to the scaled front axle weight (4,750), the GVW is 11,210 pounds. That exceeds the GVWR by 1,210 pounds. Additionally, the rear gross axle weight rating (6,200) is exceeded by 260 pounds.

The typical formula is one small reason for towing guides and the standard dealer's formula gets buyers into mismatched RV combinations that exceed the tow vehicle's certification ratings. Pulling a trailer without exceeding the weight ratings is primarily about SAFETY and vehicle longevity. Moreover, most manufacturers warn that exceeding the weight ratings may invalidate the vehicle warranty.

No. That is one reason RVTC has multiple PW/TW selections. The results you see are the actual capacity weight limits for each percentage selection. It is your decission if you wish to provide a safety margin. This may be accomplished by selecting a higher PW/TW percentage when you do not know the trailer's actual PW/TW percentage.

The certification label weight rating already includes a small percentage of a safety margin for emergency-type situations. I do not know of any reason that a vehicle or driving condition would be unsafe if it were towing up to the certification label limits. However, if one chooses to exceed the weight safety ratings or ignore required safety practices when involved in a severe accident, it could lead to a liability lawsuit and criminal charges.

Thanks for asking an excellent question. The RV Tow Check (RVTC) calculator computes four capacity formulas based on available payload, gross vehicle weight (GVW) of the vehicle to avoid exceeding the gross combination weight rating (GCWR), the gross vehicle weight rating (GVWR), and trailer weight rating (TWR).

When you see changes occur as you select different percentages, these results are based on not exceeding the GVWR. When the capacity stops changing and remains the same for the other percentage selections, the towing capacity is based on the GCWR or the TWR. In some cases, no change may occur because the vehicle has a high available payload. When there is a high available payload, towing capacity is limited by GCWR or the TWR.

The results are part of the checks and balances approach provided by RV Tow Check and the multiple formulas built into the calculator.

That is an excellent question. Let's define gross combination weight rating (GCWR) and gross vehicle weight rating (GVWR) a little more to answer your question.

The GCWR is assigned by manufacturers and includes the powertrain's capabilities. All the components that you mentioned are built into this rating. You may note that two identical vehicles with the only mechanical difference being the gear ratio will have different GCWRs and maximum towing capacities. See the Ram examples on this page: How Much Can A One Ton Truck Tow Without Exceeding Ratings?

The GVWR, as required by NHTSA, primarily considers the frames, axles, springs, braking, rims, and tires. Based on the lowest component rating within the braking and load-bearing systems, manufacturers assign the GVWR. Part of the safety requirement for GVWR is that the vehicle is expected to stop within a required distance when it is fully loaded to the max GVWR. This appears to be a primary safety concern of NHTSA when tow vehicles are overloaded by too much pin or tongue weight coming from the trailer. Some owner's manuals may state: "The towing vehicle's brake system is rated for operation at the GVWR—NOT GCWR. Separate functional brake systems should be used for safe control of towed vehicles and for trailers weighing more than 1,500 lbs. when loaded."

With these two ratings and knowing the gross vehicle weight (GVW), which plays a significant factor in actual towing capacity, RV Tow Check calculates four formulas. It selects the lowest result for the towing capacity. The product is based either on payload availability (part of GVWR) or GCWR, or the TWR. Although you did not mention your truck's GVW, it is most likely the reason for such a low tow capacity, as revealed by RV Tow Check.

Great question. The conventional tow results are the maximum recommended towing weight based on actual tongue weight regardless of a WD system or the TWR. In reality, and it took me a while to grasp it, WD systems don't really remove tongue weight from the hitch ball but redistribute the felt weight across the axles. Therefore, the result you see is the maximum towing weight regardless of a WD system. For a very informative discussion on WD systems, visit this forum thread at RV.net. Additionally, SAE recommends a TW of 10% for best towing performance.

The short answer is no. Here is a direct quote from Firestone/Ride-Rite: "Please remember that air springs do not increase the load-carrying capacity of your vehicle. *DO NOT EXCEED THE VEHICLE'S RECOMMENDED GROSS VEHICLE WEIGHT RATING (GVWR)"

All manufacturers' calculations are primarily gross combination weight rating (GCWR) minus GVW or curb weight equals towing capacity. (Ram's calculator does [did] have a slider scale that includes payload adjustments.) The manufacturer's published GVW is the curb weight. By the time anyone drives a vehicle off the lot, it will most likely exceed the published curb weight. Moreover, by the time anyone has their truck ready for towing, it will be much heavier. All this additional vehicle weight may reduce towing capacity.

Additionally, no tow vehicle's gross vehicle weight rating (GVWR) and gross axle weight rating (GAWR) should be exceeded because of safety and vehicle longevity. All manufacturers state that in print, and most owners never read it. None of the manufacturers take into account the GVWR when calculating tow ratings.

(If one would use a calculator and crunch Ram's sliding scale calculator results, they'll discover it doesn't add up correctly.) Note: Apparently, Ram reacted to my, and maybe others, concerns on this, and they have removed the slider scale starting with the 2016 models.


Thank you for asking that question. RVTC's primary purpose is to assist the buyer with their potential new vehicle purchase. A new vehicle purchase can be complicated, and many buyers are not sure if the vehicle they are considering has enough towing capacity to tow their trailer, or in other cases, the prospective trailer they are considering buying.

On the other hand, like many others, you have discovered from using RVTC that you may be towing with an overloaded truck. The only way to know if your tow vehicle is exceeding or not exceeding the weight safety ratings is to weigh your rig. Weighing your rig is not difficult. There is a simplified four-step weighing program available at Fifth Wheel Street. Start with Step 1 by downloading and printing the appropriate worksheet for the type of scale you plan to weigh on. The worksheet is detailed and explains the process step-by-step. Once you've completed the worksheet after the two weigh-ins, complete Step 3 after installing my app on your mobile device. Details and app store links are at the Fifth Wheel Street app website. Enter the weight data to obtain the only industry-leading 13-point RV weight safety report.

Hopefully, your rig is not overweight. Even if you discover that some of your vehicle's weight safety ratings are exceeded, you are better off knowing than driving unknowingly down the road while exceeding the ratings. It is my hope that you would at least be conscious of an overload condition and change your driving habits accordingly. Depending on how excessive the overweight may be, you may need to consider measures to eliminate the overweight condition. Most importantly, I hope you will drive and tow safely.

Additionally, you may be interested in reading the following article: My Truck Pulls it Just Fine!

It is not uncommon to find a hitch assembly installed that is rated more or less than the manufacturer's published TWR. Considering that the hitch assembly comprises the three primary components you mentioned, each component may be weight-rated differently. When considering the hitch assembly components and the published TWR, the lowest rating component will be the maximum tow rating.

i.e., If the ball is rated at 16,000 pounds and it's the lowest rating among these components and the published TWR, 16,000 pounds will be the maximum tow rating. However, suppose your truck towing capacity results in RV Tow Check (RVTC) is less than the hitch assembly components and published TWR. In that case, it is recommended you not tow more than the capacity as indicated by RVTC.

Yes, I recommend it. The most common weight safety issue for motorcoaches is exceeding the vehicle's gross combination weight rating (GCWR). As for the tongue weight (TW) measurements, there is a little more flexibility in this area depending on the towing method. If you're towing a car with all four wheels on the ground (flat tow), expect minimal TW. Even when towing a vehicle on a dolly, the TW will remain reasonably low. Ensure you're not exceeding the rear gross axle weight rating (GAWR) by weighing your motorcoach with the dolly and car attached.

Now, if you're towing a conventional trailer, read the max conventional towing capacity the same as any other conventional towing combination.

Finally, I strongly encourage you to weigh your fully-loaded motorcoach with any TOAD to ensure you're not exceeding any of the weight safety ratings. Weighing is easy by following the simplified four-step plan at Fifth Wheel Street.

Absolutely! I encourage any recommendation that you may have for any app I've created. Even if you think something doesn't appear to be correct with an app, I especially want to hear from you. All feedback is welcome.

No. Rarely will the published dry pin weight percentage be an acceptable representation of a loaded trailer’s pin weight percentage. In many cases, the pin weight of identical trailers will be different between two separate families. It all depends on how the trailer is loaded.

Example: The published dry pin weight percentage for my 2009 Heartland Cyclone is about 22%. My loaded trailer's actual pin weight percentage has ranged between 17% to 20%. I have a record of one trailer, and the dry pin weight is 19%, but the loaded pin weight was 26%.

I recommend buyers who do not know the loaded pin weight of a trailer to select the maximum pin weight percentage on the scale when selecting a new tow vehicle.

Absolutely! Short wheelbase vehicles such as some SUVs, vans, half-ton and three-quarter-ton pickup trucks have limitations in towing safety and stability.

Some time ago, there used to be a thumb rule for tow vehicle wheelbase length versus trailer length. That rule no longer exists, and there is currently no verified replacement.

I recommend you read the tow vehicle owner’s manual. Many owner’s manuals provide a maximum frontal trailer limitation. Measuring and knowing the trailer’s frontal area alone may prevent towing many trailers from being pulled by short wheelbase vehicles.

Several accidents occur annually due to trailers being too long for the tow vehicle. Read one such true story here.