Pull into any Outer Banks campground and you will see some beautiful rigs: crew-cab diesel duallies, polished, well cared for and built to pull a house down the highway. Their owners love them, and for good reason. For a big fifth wheel or a long haul through the mountains, a heavy-duty diesel is the right tool.
This guide is another point of view, written for buyers who have already done their homework. It runs the 2027 numbers (ratings, engines, option prices, fuel, upkeep and resale) and lays out where the diesel earns its price and where a gas truck does the same job for less. A lot of RVers tow a few weekends a year and drive the truck every other day. If that sounds like you, the numbers are worth a look before you sign for six figures.
The short answer: match the truck to the trailer
Start from the loaded weight of the trailer you own or plan to buy, not the truck you like. This is how the classes usually line up:
| Loaded trailer | Truck that usually fits | What to watch |
|---|---|---|
| Travel trailer up to about 8,000 lb | Half-ton with the max-tow package, or a three-quarter-ton gas | Payload runs out before the tow rating |
| Travel trailer 8,000–12,000 lb, or a lighter fifth wheel | Three-quarter-ton gas | Payload and rear axle rating |
| Fifth wheel 12,000–16,000 lb | Three-quarter-ton or one-ton, gas or diesel | Pin weight; diesel pulls ahead with mountain miles |
| Fifth wheel over 16,000 lb, or very heavy pin weight | One-ton diesel, often a dually | This is the diesel dually’s home turf |
Know your numbers
Every tow rating you see in an ad is the best case for one configuration. The numbers that decide whether a specific truck can pull your trailer are on the truck’s door-jamb labels and in the maker’s towing guide:
- GVWR (gross vehicle weight rating): the most the loaded truck may weigh, passengers and cargo included.
- GCWR (gross combined weight rating): the most the loaded truck and loaded trailer may weigh together.
- GAWR (gross axle weight rating): the most a single axle may carry. The rear axle is often the first limit you hit.
- Payload: everything the truck carries, including people, gear, the hitch and the trailer’s tongue or pin weight.
- Tongue weight: usually 10 to 15% of a loaded conventional trailer. Pin weight on a fifth wheel usually runs 15 to 25%.
Pickup tow ratings are set under SAE J2807, an industry standard for trucks up to 14,000 lb GVWR that includes a long, hot climb up Davis Dam grade in Arizona, so ratings compare on the same terms. Many experienced RVers also leave a margin and keep the loaded trailer near 80% of the rating. That is a rule of thumb, not a factory requirement, but it is a good one.
Payload and tongue weight
Tow ratings get the headlines, but payload is often the number that runs out first, especially on a half-ton. Two examples:
- A 7,500-lb loaded travel trailer puts 750 to 1,125 lb on the hitch. Add two adults (about 350 lb) and 200 lb of gear in the truck, and you are using 1,300 to 1,675 lb of payload before you count the hitch itself. The 2027 half-tons top out between about 1,500 and 2,450 lb of payload depending on engine, and a well-optioned crew cab sits below its brand’s maximum.
- A 14,000-lb loaded fifth wheel puts 2,100 to 3,500 lb on the pin. With the same people and gear, that is 2,650 to 4,050 lb. A 2027 Ram 2500 is rated for up to 3,990 lb of payload with the Cummins and up to 4,580 lb with the gas Hemi and payload package, which is one reason a heavy fifth wheel often pushes buyers to a one-ton.
Notice that the gas truck carries more. A gas V8 weighs less than a diesel, so the same truck usually has a higher payload rating with the gas engine. Check the payload on the yellow sticker in the driver’s door jamb of the exact truck you are buying, and remember that brochure trailer weights are often for a base model with empty tanks. Fresh water weighs about 8.34 lb a gallon, so a full 40-gallon tank adds roughly 330 lb.
The most reliable number is a scale ticket. A CAT Scale at a truck stop weighs the steer axle, drive axle and trailer axles on separate platforms, which shows your axle loads as well as the total. The first weigh costs $15.25 and a reweigh within 24 hours is $5.25.
The 2027 trucks, side by side
The heavy-duty lineup changed a lot for 2027, and anyone shopping from last year’s notes should know it. Ford dropped the 6.8-liter gas V8 and the standard-output diesel, so the 7.3-liter gas V8 is now standard and the high-output 6.7-liter Power Stroke is the only diesel. GM replaced the 6.6-liter Duramax with a new 8.3-liter Duramax V8. Ram carries over its 6.4-liter Hemi and 6.7-liter Cummins.
| Three-quarter-ton / one-ton | Gas V8 | Diesel | Diesel option |
|---|---|---|---|
| Ford Super Duty | 7.3L: 430 hp, 485 lb-ft | 6.7L Power Stroke H.O.: 500 hp, 1,200 lb-ft | About $12,500 |
| Ram 2500/3500 | 6.4L Hemi: 405 hp, 429 lb-ft | 6.7L Cummins: 430 hp, 1,075 lb-ft | $12,995 on the Power Wagon |
| Chevy Silverado HD / GMC Sierra HD | 6.6L: 412 hp, 472 lb-ft | 8.3L Duramax: 555 hp, 1,230 lb-ft | $11,400 |
The gap in towing ratings is real, and it grows with the truck. A 2027 Ram 2500 is rated to tow up to 17,740 lb with the Hemi and 20,000 lb with the Cummins; a Ram 3500 goes to 18,140 lb with the Hemi and 37,020 lb with the Cummins. Chevy rates its gas HD for up to 19,000 lb and the new 8.3-liter Duramax for up to 38,000 lb with a gooseneck. Those are preliminary 2027 maximums for the best-equipped configuration; the truck on the lot will be rated lower. Below about 14,000 lb, every gas HD on this list tows with that 80% margin intact. Past the low 20,000s, it is diesel only.
For lighter trailers, the 2027 half-tons are worth a look:
| Half-ton | Best towing engine | Max towing | Max payload |
|---|---|---|---|
| Ford F-150 | 3.5L EcoBoost V6 | 13,500 lb (4x4) | 2,175 lb (4x4) |
| Ram 1500 | 3.0L Hurricane I-6 | 11,530 lb | 1,880 lb |
| Chevy Silverado 1500 | 5.7L V8 | 13,700 lb | 2,170 lb |
What the diesel costs up front
On 2027 heavy-duty pickups, choosing the diesel over the gas V8 adds roughly $11,400 to $13,000 depending on the brand. A 2027 Silverado 2500HD runs from about $50,000 for a Work Truck to about $78,000 for a High Country before the diesel. Add the diesel, an upper trim and, on a one-ton, dual rear wheels, and a diesel heavy-duty truck can sticker above $100,000. A dually does not have to be a diesel, either: Ford, Ram and Chevrolet all sell one-ton duallies with a gas V8.
What it costs at the pump
Diesel has long been the fuel-economy winner, and it still gets more miles per gallon. The catch is the price per gallon. In the U.S. Energy Information Administration’s weekly survey for November 2, 2026, regular gasoline averaged $4.15 a gallon and on-highway diesel averaged $6.29. That is about 52% more for diesel, so a diesel has to get roughly 52% better mileage just to break even on fuel.
Real tests show a much smaller edge than that. In TFLtruck’s April 2026 towing loop, a Ram 2500 Cummins pulling about 4,000 lb averaged 13.2 mpg to the Hemi’s 11.1, about 19% better. Because diesel cost more, the fuel for the 123-mile loop came to $47.45 for the Cummins and $49.52 for the Hemi, nearly a wash, and TFL figured it would take about 639,000 miles to earn back the engine option on fuel alone. Empty, TFL’s 2024 F-250 test had the diesel at 19.6 mpg and the 7.3-liter gas at 16.6.
Here is a simple year of driving: 3,000 miles towing and 9,000 miles of everyday driving. The gas figures come from the Cars.com F-250 test with the 7.3-liter V8 (8.4 mpg towing 12,500 lb, about 14.9 mpg empty). The diesel figures, 12 mpg towing and 17 mpg empty, give the diesel a bigger towing advantage than TFL measured.
| One year, 12,000 miles | Gas V8 | Diesel |
|---|---|---|
| 3,000 miles towing | $1,482 | $1,572 |
| 9,000 miles everyday | $2,507 | $3,330 |
| Fuel for the year | $3,989 | $4,902 |
Even with the better mileage, the diesel costs about $910 more in fuel that year, before the option price. Fuel prices move, and when the diesel premium shrinks the math gets closer, but at recent prices a diesel does not pay for itself at the pump unless you tow heavy and tow a lot.
Upkeep, warranty and resale
Fuel is not the only running cost, and not every difference favors gas:
- Diesel exhaust fluid (DEF). Modern diesels use DEF at about 3 to 5% of the fuel they burn. In the example year above that is roughly 23 to 39 gallons, or about $100 to $180 at recent truck-stop pump prices.
- Oil and filters. Ram’s owner’s manual calls for about 12 quarts of oil in the Cummins and about 7 in the Hemi, and the diesel uses two fuel filters. Kelley Blue Book puts a diesel fuel filter replacement on a Super Duty at $90 to $207.
- Emissions system. A diesel’s particulate filter cleans itself during steady highway driving. Trucks that mostly idle or make short trips around town can struggle to finish that cleaning; Ford issued a service bulletin for 6.7-liter Super Duty trucks used that way. If the truck spends most of its week on errands, that matters.
- Cold weather. No. 2 diesel starts to cloud around 15°F, so winter travelers north of here use a winter blend.
- Warranty, a diesel plus. Ford covers diesel engine parts for 5 years or 100,000 miles, and GM’s Duramax coverage has also run 100,000 miles, versus 60,000 on gas powertrains.
- Tires. A dually runs six tires instead of four, and replacing six costs more.
Resale is the diesel’s best counterargument. Heavy-duty pickups hold their value well overall: iSeeCars puts the segment at about 76% retained after five years, with the Ram 3500 and F-350 near 80%. Older auction data on a 2012 F-250 showed the diesel keeping about 70% of its original price premium after four years, and holding up far better than the gas truck past 150,000 miles. If you keep a truck to high mileage, much of the diesel option comes back when you sell.
Where the diesel earns its keep
None of this takes anything away from what a diesel does well. If these describe your camping, the diesel is worth every dollar:
- Heavy trailers. Past the low 20,000s, the gas trucks are out of the running, and the diesel one-tons are rated far beyond any gas pickup.
- Mountain grades. With 1,075 to 1,230 lb-ft of torque, a diesel climbs with far less effort. All three gas HD V8s are naturally aspirated, without a turbocharger, so they lose power as the air thins at altitude; a turbo diesel holds its power much better.
- Coming down. Ford, Ram and GM diesels have a factory exhaust brake that holds speed on a long downhill without riding the service brakes. Gas trucks rely on tow/haul mode and downshifting, which helps but does not hold as well.
- Range and longevity. Better mileage and tanks of up to about 50 gallons mean fewer fuel stops with a trailer, and a diesel’s resale holds up at high mileage.
Single rear wheel or dually
A dually adds stability and rear-axle capacity under a heavy pin weight, and it is steadier in crosswinds. The trade-off is width: a Ram 3500 dually is about 96.5 inches across the rear fenders, compared with about 83.5 inches for the single-rear-wheel version. That is the difference between fitting a parking space, a drive-through or a garage and not. RV sources generally treat a dually as a choice rather than a requirement until fifth wheels get past about 14,000 to 16,000 lb or carry a very heavy pin weight.
Why a dually and the beach don’t mix
A dually is built for stability with a heavy load on pavement, and that is where it shines. Soft sand is a different job. Driving the Outer Banks beaches means letting the tires down to 18–20 psi so they float on the sand, and a dually can’t do that well: aired down, the inner and outer rear tires bulge into each other and rub. The rear wheels also sit wider than the fronts, so instead of rolling in the tracks the front tires just made, the outer duals cut fresh ruts, which takes more power and digs in faster. Add the weight of a heavy-duty diesel, and a stuck dually is a hard truck to get out.
The rest of the year
Most tow vehicles spend far more time going to the store than pulling a camper. A truck you enjoy on a Tuesday matters: one that fits a parking space, rides well empty and is fun on a back road or a beach. Plenty of gas half-ton and three-quarter-ton pickups, including the off-road trims, tow a typical travel trailer comfortably and are a pleasure to drive the rest of the time. If you are shopping that way, OffRoad.guide compares half-ton and three-quarter-ton pickups side by side and ranks the best off-road trucks by trim and price.
That is also why so many RVers who come to the Outer Banks leave the big rig at the campground and use a smaller 4x4 for the beach. Our sister site OBX Jeep Rentals rents beach-ready Jeeps with both beach permits installed: pick up in Kill Devil Hills and park your car or RV there free.
Questions to ask before you buy
- What does my trailer weigh loaded, from a scale ticket, and what is its tongue or pin weight?
- What payload is on the door sticker of this exact truck, and how much is left after the hitch, people and gear?
- Does this truck’s axle ratio and package match the tow rating I am counting on?
- How many miles a year will I tow, and how many will I drive empty?
- Do I tow through mountains, or mostly flat coastal highways?
- How much of the truck’s week is short trips and idling?
- Will the truck fit my garage, my driveway and the places I park every week?
- Have I driven the gas version of the same truck, loaded and empty?
Frequently asked questions
Do I need a diesel to tow a fifth wheel?
Not always. A three-quarter-ton gas truck is rated for many fifth wheels up to the mid-teens of thousands of pounds, as long as the pin weight fits its payload. A diesel becomes the clear choice for heavy fifth wheels, frequent mountain towing and anything over the low 20,000s.
Is a half-ton enough for a travel trailer?
For many travel trailers up to about 8,000 lb loaded, yes, if the payload covers the tongue weight, the hitch, the people and the gear. Payload, not the tow rating, is usually the limit.
Does a diesel pay for itself in fuel?
At recent prices, no. Diesel has cost about half again as much as gas per gallon, more than the diesel’s mileage advantage in published towing tests. Resale value and longevity are where a diesel gets its money back.
What is the best RV tow vehicle?
The one rated with margin for your loaded trailer that you also like driving empty. For most travel trailers that is a well-equipped half-ton or a gas three-quarter-ton; for big fifth wheels it is a one-ton diesel.
There is no wrong answer. If the diesel dually fits how you camp, enjoy it. If it doesn’t, a lighter truck may save money every week and be more fun to own.
Sources
- U.S. Energy Information Administration, gasoline and diesel retail prices (week of November 2, 2026)
- Cars.com, F-250 7.3-liter gas mpg while towing 12,500 pounds
- TFLtruck, Ram 2500 Cummins vs. Hemi towing mpg loop (April 2026)
- TFLtruck, 2024 F-250 gas vs. diesel highway mpg
- Stellantis, 2027 Ram Heavy Duty specifications
- Chevrolet, 2027 Silverado HD
- Motor1, 2027 Silverado HD diesel price
- Ford Authority, 2027 Super Duty engine lineup
- The Drive, 2027 Ram Power Wagon Cummins price
- Ram, 2027 Ram 1500 capability
- AutoGuide, 2027 Ford F-150 towing and payload
- Ford, RV and Trailer Towing Guide (definitions, tongue and pin weight)
- etrailer, choosing a truck for a fifth wheel
- Camping World, RV trailer weight ratings
- CAT Scale, how to weigh
- Cummins, diesel exhaust fluid consumption
- Ford TSB 21-2052, 6.7L exhaust filter cleaning (NHTSA)
- Ford, diesel engine warranty
- iSeeCars, heavy-duty truck resale value
- Vehicle Remarketing, diesel truck residual values
