Choosing a truck to pull a trailer is a critical decision for RVers, because getting there, and particularly getting there safely, is the first and most important part of enjoying the RV lifestyle! Towing specs and towing guidelines always give the outer limits of what a truck can safely tow. Too often, in towing situations, the trailer is a little too big for the truck, or the truck is a little too small for the trailer, pushing the truck right to its outer safety limits or beyond.
The truck-trailer combo may be just a little out of spec on paper, so it may seem okay, like you can get away with it, but it is a really unwise decision. Not only is it absolutely no fun to drive a truck that is screaming its little heart out to tow the load its tied to, but if you have an accident and it is determined your truck was towing a load that is beyond its safety limits, you will be liable.
Heaven forbid that there is a fatality in the accident — either yours or someone else’s. There are lots of horror stories out there of people’s lives that were transformed because someone decided not to get a truck that could tow their trailer safely.
Of course, truck and trailer salesmen don’t help. We have heard time and again, “That truck is fine for this trailer,” or “This trailer will be no problem for that truck.” Don’t listen to them! Trust your instincts and your gut feelings. If you are studying the specs and are nervous that your truck *might* be too small because your trailer puts it on the hairy edge of its specs, then you need a bigger truck or a smaller trailer.
Sizing a Truck and Trailer for Safe Towing
This article covers all the specifications we studied and were concerned about when we placed the order for our 2016 Ram 3500 truck to tow our 14,100 lb. 5th wheel trailer. You can navigate to the various sections with these links:
- The Trade-in: ’07 Dodge Ram 3500
- Weight Ratings Demystified
- Diesel Trucks on the Market
- Long Bed vs. Short Bed, Single vs. Dual Rear Wheel
- Test Drives – Choosing a Truck Brand
- Horsepower, Torque, Towing & Payload Capacities
- AISIN Transmission
- Rear Axle Gear Ratio
- Four Wheel Drive
- Puck System Hitch Mounts and Other Features
- The Option List for Our 2016 Ram 3500 Dually Truck
The Trade-In – 2007 Dodge Ram 3500 Single Rear Wheel Long Bed diesel truck with 6.7 liter Cummins engine
When we bought our 2007 Dodge Ram 3500 Single Rear Wheel long bed diesel truck with the 6.7 liter Cummins engine, its purpose was to tow a 7,000 lb. (fully loaded) 2007 Fleetwood Lynx travel trailer. Our 2004 Toyota Tundra (4.7 liter engine) had been okay to tow that trailer on paper, but when we took it on its first mountain excursion up and over Tioga Pass on the eastern side of Yosemite in California, it could not go faster than 28 mph with the gas pedal all the way to the floor. What a scary, white knuckle drive that was. Who needs that?
We replaced the Toyota Tundra with a 2007 Dodge Ram 3500 which was rated to tow much bigger trailers than the little Lynx travel trailer, so all was good with that small travel trailer. However, within a year, we upgraded our trailer from the lightweight Fleetwood Lynx to a full-time quality, four season, 36′ NuWa Hitchhiker LS II fifth wheel trailer that the scales told us was 14,100 lbs. fully loaded. Suddenly, our big beefy diesel truck was at its outer limits!
We drove our ’07 Dodge Ram 3500 and 36′ fifth wheel combo for seven years without a mishap, but it was not an ideal situation. The truck would strain in the mountains and would wander in strong cross winds on the highway. We installed a K&N Cold Air Intake Filter and an Edge Evolution Diesel tuner which helped the engine breathe better and increased its power (see our Edge Evolution Tuner Review), and we installed a Timbren Suspension Enhancement System to keep the truck from sagging when hitched to the trailer. But the frame of the truck and the transmission were still stressed by the heavy load on steep inclines.
We wanted a truck that was well within its towing limits and that could tow our trailer effortlessly.
TRUCK and TRAILER WEIGHT RATINGS
The weight ratings for trucks and trailers are an alphabet soup of confusion that takes a little imagination to grasp. Here’s a synopsis:
|UVW||Unloaded Vehicle Weight||The weight of the vehicle without fuel, people and stuff|
|GVWR||Gross Vehicle Weight Rating||The heaviest weight the vehicle can safely be when it is loaded up with fuel, people and stuff|
|GCWR||Gross Combined Weight Rating||The most a truck-and-trailer combo can safely weigh when hitched together and loaded up with people, fuel, food, etc|
|Payload||The GVWR less the UVW||The amount of weight the truck can safely carry. Compare to the trailer’s Pin Weight|
|PW||Pin Weight||The actual weight on the truck’s rear axle when a trailer is hitched up. Compare to the Payload|
The Pin Weight is most easily visualized by first imagining yourself standing on a bathroom scale and making a note of your weight. Then your teenage kid walks up and puts his arms around your neck and hangs on your shoulder. The weight on the scale goes up a little bit, but not a huge amount, because your kid is still standing on the floor on his own two feet. The more he leans on you, the more weight the scale shows.
The difference between the weight the scale shows when your kid is hanging on your shoulder and the weight it shows when you’re by yourself is the “pin weight.” In the case of you and your kid, the “pin weight” might be 30 lbs.
The following chart shows the factory safety weight ratings given by Chrysler and NuWa and the actual weights for our ’07 Dodge Ram 3500 truck and ’07 36′ NuWa Hitchhiker 5th Wheel trailer. We had our rig weighed by the Escapees Smart Weigh program at their North Ranch RV Park in Wickenburg, Arizona. This is a detailed, wheel by wheel, RV specific method of weighing.
Our truck, when loaded, carries fuel, 24 gallons of water, a generator and BBQ, the fifth wheel hitch, several leveling boards, two huge bins of “stuff” and ourselves, as well as the pin weight of the trailer. So, even though the pin weight itself was within tolerance on our ’07 Dodge 3500, all that other stuff made the truck way overweight. Moving those things to the trailer would clog our fifth wheel basement and would just make the trailer way overweight instead.
2007 Dodge Ram 3500 SRW (Single Rear Wheel) Truck
* LOADED with passengers, fuel and cargo but not towing
2007 NuWa Hitchhiker 34.5 RLTG Fifth Wheel Trailer
We improved our trailer’s cargo carrying capacity by upgrading from E rated tires to G rated tires and by revamping the suspension completely (I have not yet written about that project). So, even though some elements of the trailer frame are still at the spec limit, we have some leeway with our trailer in those places where the rubber meets the road.
The truck, however, was over its limit for both GVWR and GCWR, and it was pushed nearly to its max when towing.
The 2007 Ram 3500 towing guide is here: 2007 Dodge Ram Trucks Towing Guide. Our truck is on p. 20, on the 2nd to last line. Search for this text: “D1 8H42 (SRW)” (you can copy and paste it from here).
DIESEL TRUCKS ON THE MARKET
There are three brands of big diesel pickup trucks on the market: Chevy/GMC, Ford and Dodge. People have lots of brand loyalty when it comes to diesel trucks, and the bottom line is it’s pointless to get into a religious war over truck manufacturers. That said, the following are our personal opinions and there is no offense intended to anyone who loves a particular brand.
GMC makes the Chevy Silverado and GMC Sierra which both have the Chevy Duramax 6.6 liter engine and the Allison transmission. The Allison transmission is widely used throughout the commercial trucking industry and is considered to be the best.
FORD makes the Super Duty series of trucks which have Ford built engines and transmissions. Ford has modified its Power Stroke engine several times since the early 2000’s. The current engine is a 6.7 liter engine and it has performed well. Earlier models, the 6.0 liter engine and 6.4 liter engine, both had significant problems and were less reliable.
CHRYSLER makes the Ram series of trucks which have the Cummins 6.7 liter engine and Aisin transmission. The Cummins engine is widely used throughout the commercial trucking industry and is considered to be the best.
With the late model Ram trucks there are two models of 6 speed automatic transmissions to choose from. The 68RFE transmission was the only one available for our ’07 Dodge, and we found it developed problems over time (before our installation of the K&N Cold Air Intake and Edge tuner). It stuttered on climbs and didn’t always shift smoothly. The new (in 2013) Aisin AS69RC transmission is much more rugged and reliable and is now available as an option in the Ram Trucks lineup.
PICKUP TRUCK SIZES
All trucks are categorized into eight weight classes, from Class 1 (lightest) to Class 8 (heaviest) according to their GVWR. Pickup trucks fall into the smallest (lowest) three classes:
|Class 1||0 – 6,000 lbs|
|Class 2||6,001 – 10,000 lbs|
|Class 3||10,001 – 14,000 lbs|
All three classes of pickups are referred to as “light duty” trucks, as compared to dump trucks and semi tractor-trailers in the higher “medium duty” and “heavy duty” classes. Within the pickup truck market, however, they are referred to as “Pickups” (Class 1), “Full Size Pickups” (Class 2) and “Heavy Duty Pickups” (Class 3). So, even though a large diesel pickup is marketed as “heavy duty,” it is not technically a heavy duty truck. It’s just a heavy duty pickup. This may be obvious to many, but sure had me confused at first glance.
When we were first time truck buyers shopping for a truck to pull our popup tent trailer, the advertising made the ’04 Toyota Tundra look like it was a heavy duty towing monster that could pull a mountain right across a valley. But it is not so! Pickups come in all sizes.
Pickup truck sizes are referred to as “half-ton” “three-quarter ton” and “one ton,” and they are numbered accordingly:
Ford also mass markets 450, 550 and larger pickups. Some people make custom Chevy and Dodge trucks in those sizes too, but they don’t come from the factories that way.
For reference, a ton is 2,000 lbs. The truck naming convention comes from the original payloads these trucks could carry when they were first introduced decades ago. Back in those days, a half-ton truck could carry 1,000 lbs. (half a ton) in the bed of the truck. A three-quarter ton could carry 1,500 lbs and a big one ton truck could carry 2,000 lbs.
In 1918 Chevy had a very cute half-ton pickup that was basically a car with sturdy rear springs. By the mid-1930’s pickups came with factory installed box style beds, and a 1937 Chevy half-ton truck went on a 10,245 mile drive around the US with a 1,060 lb. load in the bed. It got 20.74 miles to the gallon!
As the payload capacities increased, the manufacturers assigned model numbers that corresponded to the weights the trucks could carry. But technology advances never quit!
Since those early times, truck and engine designs have improved dramatically, and the payloads modern trucks can carry now is significantly higher. For instance, the payload of a 2016 Toyota Tundra, a half-ton truck, is 1,430 to 2,060 lbs., depending on the options, making it essentially a “one ton” truck. The payload of a 2016 Dodge Ram diesel can be as high as 6,170 lbs. (and even higher for the gas HEMI version), making the 3500 model more of a “three ton” truck than a one ton.
In the modern trucks, the major difference between a three quarter ton 250/2500 truck and a one ton 350/3500 truck is the beefiness in the rear end suspension for supporting a heavy payload, that is, the number of leaf springs on the rear axle. In our opinion, if you are going to spend the money to buy a three quarter ton truck for towing purposes, you might as well spend the tiny incremental extra few bucks to buy a one ton.
LONG BED vs. SHORT BED PICKUPS
Pickups come with more than one bed size. A “short bed” truck has a box that is a little over 6′ long and a “long bed” truck has a box that is around 8′ long. When a fifth wheel hitch is installed in the bed of a pickup, it is placed so the king pin of the fifth wheel will be over the rear axle. In a short bed truck this leaves less distance between the hitch and the back of the pickup cab than in a long bed truck.
The advantage of a short bed truck is that the two axles are closer together, so the truck can make tighter turns. This is really handy in parking lots and when making u-turns. The truck also takes up less space when it’s parked, again, a big advantage in parking lots.
However, when towing a fifth wheel trailer, there is a risk that the front of the fifth wheel cap will hit the back of the pickup cab when making a tight turn. For this reason, there are special sliding fifth wheel hitches, and some 5th wheel manufacturers make the fifth wheel cap very pointy and even concave on the sides so there’s room enough to ensure the pickup cab doesn’t touch the fifth wheel cap on tight turns.
The advantage of a long bed truck is that not only can it carry more and bigger things in the bed of the truck, but when it is hitched to a fifth wheel trailer, doing a tight turn will not risk the front of the fifth wheel hitting the back of the truck cab.
Also, you can open and close the tailgate when the fifth wheel trailer is hitched up. We can actually walk from one side of our trailer to the other through the gap that’s between the open tailgate and the front of the trailer, even when the truck is cocked in a tight turn.
For folks that use their pickup primarily in non-towing situations and take their fiver out for just a few weekends a year (and stay close to home), a short bed truck is fine. However, in our opinion, if you are going to tow a large fifth wheel frequently, and especially if you are a seasonal or full-time RVer traveling longer distances, a long bed truck is the way to go.
We bought a long bed as our first diesel truck for our little travel trailer, knowing we might eventually get a fifth wheel, even though it takes much more real estate to back a travel trailer into a parking spot with a long bed truck that it does with a short bed truck (because the pivot point on a travel trailer is behind the bumper rather than over the truck axle, forcing the front end to swing exceedingly wide to make a turn).
When we use our truck as a daily driver, even though we always have to park away from the crowd and walk a little further, and we sometimes struggle making u-turns and maneuvering in tight spaces (it takes nearly four lanes to do a U-turn in a long bed pickup without the trailer attached), we have never once regretted having a long bed truck.
SINGLE REAR WHEEL vs. DUAL REAR WHEEL (DUALLY)
In the one ton class of trucks (Ford 350, Chevy/Dodge 3500), there is an additional consideration: single wheels on the rear axle of the truck (“single rear wheel”) or two pairs (“dual rear wheel” or “dually”).
The advantages of a single rear wheel truck are:
- Only 4 tires to maintain instead of 6
- Changing a flat will never involve accessing an inner tire under the truck
- No wide rear fender to worry about at toll booths and drive-through bank windows and fast food windows
- Easy to jump in and out of the bed of the truck from the side using the rear wheel as a foothold
- Can handle rough two track roads better because the rear wheels fit neatly into the ruts
- Gets traction on slick ice, snow and muddy roads better than a dually
The advantages of a dual rear wheel truck (“dually”) are:
- Wider stance supporting the weight of the king pin (or bumper hitch)
- Can carry a heavier payload — heavier trailer pin weight and/or bigger slide-in truck camper
- Much safer if there’s a blowout on one of the rear wheels, and you can still drive (for a while)
Why do you need to get in and out of the truck bed from the side? Climbing in on the tailgate is great, and there is a very handy foothold at the license plate mount on the 2016 model that is low enough for a short person to reach easily. However, when the truck is hitched to the fifth wheel, it’s not possible to climb in from the tailgate, and sometimes we need to get into the bed of the truck when the fiver is attached!
For instance, we keep 22 gallons of spare water in the bed of the truck in 5.5-gallon jerry jugs. I’m the one who holds the hose in the jugs while Mark goes to the other end of the hose and turns the water on or off at the spigot. We could switch roles, but I like that job!
When we’re hitched up, I have to get into the bed of the truck from the side to get to the water jugs. I plant one foot on the rear tire, and I hoist myself up and over the side. Getting over that fat fender is not so easy with the dually!
When hitching/unhitching, Mark also reaches over the side of the truck to loop the emergency break-away brake cable from the trailer onto the hitch in the truck bed. That way, if the trailer comes unhitched as we’re driving, the quick yank on the small cable (as the trailer breaks free) will engage the trailer’s own brakes as we wave it goodbye behind us.
Obviously, for both of these maneuvers, the width of the dually fender makes reaching into the bed of the truck a whole lot harder. Doing these things on a single rear wheel truck is trifling by comparison!
RESEARCHING SINGLE REAR WHEEL vs DUALLY TRUCKS
Our biggest debate was whether or not we should simply buy a new single rear wheel truck that had the latest engine and drive-train and chassis improvements or if we should take the plunge and get a dually. We do occasional research online, but our preferred method of learning about things in the RV world is to talk to experienced people in person, especially since we are out and about all day long and we enjoy meeting new people.
So, we interviewed every single dually truck owner that we ever saw. For two years! Whenever we saw a dually parked somewhere, we’d look around to see if the owner was anywhere nearby. If so, we’d walk up and ask him about his truck.
Did he like it? What did he tow with it? How long had he had it? Was it his first dually? Did he have trouble maneuvering in tight quarters? Had he towed that same trailer with a single rear wheel truck? How did they compare?
To our astonishment, although we searched for two years for a person who had towed the same large fifth wheel trailer with both a dually and a single rear wheel truck, and we talked to dozens of dually truck owners who had towed all kinds of trailers, we found only one who had towed the same fifth wheel trailer with both styles of truck.
This guy was a rancher with several big cattle and horse trailers as well as a 40′ toy hauler fifth wheel. He’d been towing comparable trailers with single rear wheel long bed trucks for over twenty years. Three years ago he’d switched to a dually, and he said the difference for his toy hauler was night and day. He’d never go back.
Another fellow told us the ranch he worked on had both single rear wheel and dually trucks and that the duallies were used exclusively for the big trailers because they were better tow vehicles.
This was very convincing, but an interesting side tid-bit we learned is that many folks go either dually or single rear wheel when they buy their first diesel truck for a big trailer, and they stick with that type of truck when they replace it. Guys love their trucks, so we heard few complaints, but when folks raved about how their single rear wheel or dually was the ultimate towing machine and that they’d never switch, when pressed for details, we found they didn’t have first-hand experience using the two different types of trucks to tow the same large trailer.
For those looking to conduct their own research, in addition to talking with ranchers and horse owners, one of the best sources of information we found was the trailer transport drivers who drive their own personal trucks to tow both large RV and horse trailers from the manufacturers to the dealerships where they are sold..
TEST DRIVES and CHOOSING A TRUCK BRAND
Our questions would have all been answered in a heartbeat if we could have hitched our trailer onto a dually sitting in a truck dealership lot and towed it up a mountain and on a few back roads. However, that wasn’t possible.
Perhaps in the future, because of the fantastic new hitch puck systems that can be factory installed in pickups these days, dealerships will decide to keep one of the nifty B&W OEM fifth wheel hitches on hand for prospective customers to do just that (if they can sort out the liability and insurance issues).
Ultimately, we held out on the dually versus single rear wheel decision until the very end, but we knew inside that if we did buy a new truck it would probably be a dually. So every test drive we did was with a dually truck.
We took all three brands of pickups out on over 200 miles of test drives at 25 or so dealerships.
Dealing with Slick Salesmen
A reader wrote me recently to say he was intimidated by the sales tactics at car dealerships, so he was reluctant to do many test drives or much dealership research. That is a real shame, because the only way to learn about trucks is to spend time with them, test drive them, sit in them, crawl underneath, study what’s under the hood, read the marketing literature, and hound the salesmen with questions.
After all, the salesmen are there to teach you what you need to know about the product, and if they don’t sell you a truck today, they are helping another salesman (or themselves) sell you a truck tomorrow. What goes around comes around, and any good salesman understands that. You can easily deflect the high pressure sales tactics by saying, “We are starting our search and just want to do a test drive today. We won’t be ready to buy for a few months.”
Where to Do a Test Drive? Where to Buy?
The best places to find knowledgeable diesel truck salesmen and buy big diesel trucks, especially duallies, is in cattle ranching country. As we scoured dealerships from San Diego to Maine and from Sarasota to the Tetons, we found urban areas generally have few big trucks on the lot and the salesmen know very little about diesel trucks. Cattle ranchers, horse owners and big commercial farmers know their trucks, and so do the salesmen they work with.
Our first test drives were focused on the turning radius and maneuverability of a dually truck as compared to the single rear wheel truck we knew so well. It was hard to tell, but the turning radius seemed to be the same or better (and we now feel the 2016 Ram dually definitely turns tighter) than our old 2007 single rear wheel Ram.
As for general maneuverability, Mark didn’t notice a whole lot of difference driving a dually versus our single wheel truck. Frankly, owning a long bed diesel truck period means you have to park in the back 40 and walk long distances anyway, so we soon realized that dealing with a dually in parking lots would be no different.
We did one round of comparative test drives on the uphill entrance ramp to an interstate in Baker City, Oregon. We visited each truck dealership in town, and when we did our test drives, we floored each dually truck on the incline to see how powerful it felt. The 2015 Chevy won by a long shot, against the Ford and Dodge 2015 models, but did not feel as powerful as our single rear wheel ’07 Dodge Ram (at that point our truck had the K&N Cold Air Intake and Timbrens but did not have the Edge Evolution Diesel tuner).
Deciding Factor – The Cummins Engine
In the end, the deciding factor for us for choosing a brand was the Cummins engine. This was true when we were researching our ’07 single rear wheel truck and again when researching the 2013-2016 duallies. Lots of people wish they could buy a pickup with both the Cummins engine and an Allison transmission in one brand of truck, a combo that is on many commercial trucks. But that’s not possible.
For us, the simplicity of the inline 6 cylinder Cummins engine (as compared to the more complex V8 engines in the Chevy and Ford) along with the longer stroke (inherently higher torque) makes a lot of sense. Inline engines are used commercially in big rigs and tractors, and the 6.7 liter Cummins engine has a long and solid track record, not just in Ram trucks but in many commercial applications as well. The Cummins quality control and manufacturing seem to be top notch.
Here is a fantastic video showing a Cummins engine being built:
HORSEPOWER, TORQUE, TOWING and PAYLOAD CAPACITY OF THE 2016 DODGE RAM DUALLY
Amazingly, with each passing year, the payload and towing capacity of each brand of truck jumps higher. From the time we started test driving duallies in 2013 until we placed our order for our new 2016 Ram 3500, the horsepower and torque across all three brands increased, and the towing and payload capacities climbed too.
Built with the right options, the 2016 Ram 3500 diesel truck has an eye-popping, 385 horsepower and 900 ft-lbs. of torque with a GCWR of 39,100 lbs. It can tow a trailer weighing 31,210 lbs. and has a max payload of 6,720 lbs.
This is absolutely astonishing, and neither the Chevy nor the Ford trucks match that torque right now.
Accurate comparisons between brands are challenging within the same model classes, however, because there are different standards for making measurements. Ram Trucks uses the SAE J2807 standards, while other manufacturers don’t. Also, we were able to locate Ford’s towing and payload capacity charts online (see the links at the bottom of the page), but did not locate a similar chart for GM.
Some of the head-to-head tests between the brands that are posted online are also a little misleading, because, for instance, a Ram 3500 is pitted against a Ford F450. Even though both of those models are Class 3 trucks (10,001 to 14,000 lbs GVWR), one would expect the Ram 3500 to compete head to head with the Ford F350, not the Ford F450.
Here are the towing and payload capacities of the many models of Dodge Ram trucks:
The one we ordered is on the last line of the second section on the fifth page. Search for this text: “CREW CAB LONG BOX, 4X4, DRW“
As mentioned above, the Ram trucks are sold with two options for the transmission. After our troubles with the old 68RFE transmission in our ’07 Dodge Ram 3500, we wanted the new and better one, the AISIN AS69RC. In the Ram Trucks marketing literature, the 6.7 liter Cummins engine is paired with the AISIN AS69RC transmission to make their “High Output Engine” because it delivers max torque at the low end for heavy towing situations. This combo became available in 2013.
REAR AXLE GEAR RATIO
The rear axle gearing on a pickup determines the GCWR for the truck (the maximum safe weight of truck and trailer hitched together and fully loaded) and the maximum weight trailer that the truck can tow safely. It also makes a huge difference in how the truck drives, both while towing and not towing.
Rear axle gear ratios are given as a ratio, for example “4.10” which means 4.10:1 or “3.73” which means 3.73:1. The ratio refers to the number of teeth on the axle ring gear as compared to the number of teeth on the driveshaft’s pinion gear. With a 4.10 rear end, the driveshaft has to turn 4.1 times in order to rotate the rear wheels one revolution. With a 3.73 rear end, the driveshaft must turn 3.73 times to rotate the rear wheels one revolution. So, with a 4.10 rear axle ratio the driveshaft’s pinion gear is spinning more quickly at a given speed than with a 3.73 rear axle ratio.
“Easier” Gears vs. “Harder” Gears
If you think of riding a bike, when you have the bike in a “hard” gear, it takes a lot of leg strength to turn the wheels, but one pedal stroke will cover a lot of distance. For example, going uphill in a “hard” gear would be especially hard. Your legs are turning really slowly and straining and you’re wishing you could put it in an “easier” gear! But when you descend in that same gear, you can hit high speeds easily. Back to trucks, this is like having the driveshaft turn a little to make the wheels turn a lot as it does with the 3.42 or 3.73 rear axle gear ratios found on Dodge Rams.
However, when the bike is in an “easy” gear, just a small amount of leg strength will turn the wheels, but one pedal stroke doesn’t get you very far. For example, going uphill isn’t so bad — you can inch up slowly — but once you began descending you’re spun out because your legs can’t pedal fast enough to hit super fast top speeds. In the truck world, this is like having the driveshaft turn a lot to make the wheels turn a little as it does with the 4.10 rear axle gear ratio.
Towing Heavy Loads vs. Driving Fast on the Highway
So, on a truck, the higher ratio (4.10) is ideal for towing heavy loads. It takes more turns of the driveshaft to rotate the rear wheels of the truck, so the engine revs higher, putting it in the power band for RPMs, and the heavy load gets moved. But the top end speed and fuel economy get sacrificed a bit.
With a lower gear ratio (3.73 or 3.42) it takes fewer turns of the driveshaft to rotate the rear wheels of the truck. When the truck is zipping along at highway speeds, the gears are turning a little more slowly (lower RPMs) than they would with a 4.10 rear end, which saves on fuel efficiency and makes the fastest attainable speed a little higher.
The highest tow ratings are achieved with a 4.10 rear end, so the heaviest trailers will be best if towed by a truck with a 4.10 rear axle gear ratio. However, if most of your towing is with lighter weight trailers, and your driving will be primarily on interstates, and your personal preference is to drive fast, a 3.73 or 3.42 rear axle gear ratio may make more sense.
Our ’07 Dodge had a 3.73 rear end. The problem was that at the speeds we tended to drive — 55-65 — the engine would lug. Mark manually changed gears a lot to try to keep the RPMs up, but he found it fatiguing to have to monitor the gears so closely and to change gears all the time.
We also don’t drive on interstates very often, and when we do, we’re the grannies of the road, moseying along in the right lane.
4.10 vs. 3.73 – RPMs at Different Speeds
We wanted a 4.10 rear end on our new truck, but we wanted to be 100% sure this would truly make the kind of difference we expected. So, on one Ram dually test drive we drove a stretch of highway in our ’07 Dodge at various speeds between 45 and 65 mph, noting the RPMs in a notebook, and then we took a 2015 Ram 3500 dually with a 4.10 rear end out on the same road at the same speeds. The salesman raised an eyebrow in surprise when we marched into the dealership and announced we wanted to do a test drive at various speeds to note the engine RPMs, but he went along with the idea!
On that test drive we found the 4.10 rear end shifts out of lower gears sooner than the 3.73 rear end, and generally keeps the engine RPMs about 100-200 RPMs higher at each speed. Our new truck bears out those findings.
So, how can you tell if a truck on the dealer lot has a 4.10 rear end without peering at the window sticker? Check underneath the back end of the truck. The differential is the big round casing that hangs between the rear wheels. On trucks with a 4.10 rear end, the differential has a series of vertical cooling fins on it. These help keep it cool since the gears spin faster and it is designed for heavier towing loads, both of which make it heat up.
BEEFED UP FRAME
Besides the more powerful engine tuning and transmission, Ram has improved the truck frame on the dually considerable. Every aspect of the frame is more sturdy than it used to be, making the truck not only powerful enough to pull heavier loads but strong enough to withstand the multitude of forces as it hauls the load up a mountain.
FOUR WHEEL DRIVE (4×4)
We learned with our ’04 Toyota Tundra truck towing our 7,000 lb. 27′ travel trailer that four wheel drive is a necessity for us in our RV lifestyle. In our first weeks of full-timing, a small, wet grassy incline prohibited us from camping in a campground in Texas, because our truck kept slipping and couldn’t tow the trailer up over the short rise! From that moment on, we’ve felt that a four wheel drive is mandatory if you are going to tow a big trailer.
Also, while descending a really gnarly, skinny, twisty, single lane road on a mountain in Utah, with grades of 10% or more in places, we discovered that the safest way to drive DOWN a very steep descent is to put the truck in four wheel drive LOW gear, and creep down the mountain at 5-10 mph using the exhaust brake. This tactic was a lifesaver for us on that mountain with our ’07 Dodge truck and fifth wheel trailer. Without it, we would still be living at the summit of that mountain!
The following link has more tips for driving a big RV in the mountains
PUCK SYSTEM FOR MOUNTING A FIFTH WHEEL OR GOOSENECK HITCH
The new Dodge Ram and Ford Super Duty trucks have a really fantastic option for a factory installed puck system in the bed of the truck where you can mount either a fifth wheel or gooseneck hitch. During our truck search, GM did not have that option on their trucks.
This option has five holes in the bed of the pickup, one in the center for a gooseneck hitch and four outer ones to hold a fifth wheel hitch. The idea behind this mounting system is that rather than drilling holes in your brand new truck bed to install hitch rails to support a fifth wheel hitch — the method that was always used until this new system was devised — you can buy a hitch designed for these puck mounts and simply drop it in.
If you want to use the bed of your truck for hauling, and you won’t be towing your fifth wheel, you can easily remove the fifth wheel hitch temporarily and have the entire bed of the truck available to you. Not only is it a snap to remove the hitch, but the bed of the truck will be flat and obstacle free because there won’t be any hitch rails installed in it.
Another huge benefit is that installing the hitch is an easy do-it-yourself job. We have a detailed pictorial step-by-step guide showing how to install a B&W Companion OEM Fifth Wheel Hitch here (it took just one hour from start to finish!):
To see the specs, pricing and details about this hitch, visit these links:
Our 2007 Dodge Ram came with an exhaust brake built into the turbo. Mark LOVED this brake and used it all the time, both towing and not towing. The only thing that bugged him about it was that coming down mountains with our trailer hitched on, he often had to shift gears manually and feather the gas pedal to keep the truck going the speed he wanted.
The 2016 Ram trucks have an improved exhaust brake that has two modes: max braking power and constant speed braking. We definitely wanted that option!
Dodge Ram trucks have two backup cameras, one that aims at the bed of the truck (for hitching and unhitching) and one that aims behind the truck (for backing up). Beginning in 2016, both of these cameras could be set to display their image on the main touch screen display (in the 2015 model, one camera would display in the rear view mirror while the other would display on the touch screen display).
An option on the 2016 Ram trucks is to have four leaf springs with computer controlled air bags to provide for auto-leveling of the rear suspension. This is instead of the standard six leaf springs without air bags that have a fixed height suspension.
Without the air bags — the standard configuration — the “rake” of the truck’s rear end is four inches, meaning that the rear end of the truck is raised four inches higher than the front to compensate for the weight of the trailer which will push it down when it’s hitched up. For a shorter person, this is quite high, and I was astonished how much higher the tailgate of a 2016 Ram truck sits than our old ’07 truck did.
With the air bags, the rear end is raked only one inch, making the whole back end of the truck much easier to access for those of us who aren’t that tall. In addition, there is an “Alt Ride Height” button that can be used to lower the back of the truck one more inch. Hurray for short people!
When the trailer is hitched onto the truck, pushing the truck down, the on-board compressor kicks on and pumps air into the air bags, raising the back end of the truck until it achieves its normal one inch rake. If you prefer to drive with the truck level, the “Alt Ride Height” button can be pressed to lower the back end one inch.
When we did our test drives, we found that the duallies with the auto-level suspension had a slightly smoother ride when not towing than the ordinary leaf spring only models did. This has proven true with our new truck too.
VENTED and HEATED LEATHER SEATS and STEERING WHEEL plus OTHER GOODIES
As we test drove different trim levels of trucks, we decided that if we were going to buy a new truck, we’d go all out and get the many little conveniences and options that are a “splurge” but that make using the truck a pleasure.
Heated and vented leather seats with power seat adjustments and lumbar support, a side step to make it easier to get in and out of the truck, independent climate control for driver and passenger, a CD player, OWL on/off-rad tires, the fancy electronics console with the big touch screen display and GPS nav system and power adjustable pedals were all on our list.
Most of these options are bundled into the Laramie model of the Ram 3500 trucks.
THE OPTIONS LIST FOR OUR 2016 DODGE RAM 3500 TRUCK:
- Ram Laramie Crew Cab 4×4 3500 Long Bed
- Dual Rear Wheels
- AISIN AS69RC Transmission
- 4.10 Rear Axle Ratio
- 5th Wheel / Gooseneck Towing Prep
- Auto-level rear suspension
- Diesel Exhaust Brake
- Cargo and Backup Cameras
- LT235/80R17E OWL On/Off-Road Tires
- Tubular side steps
- Power adjustable pedals
- CD player
- Top level Nav/GPS Display with voice activation and climate control
- Tan colored Heated/Vented Leather Seats and Steering Wheel
The Tow and Payload Ratings for the 2016 Ram 3500 dually with the above options as compared to our 2007 Dodge Ram 3500 single rear wheel are the following:
|Rating||2016 Dually||2007 SRW||Trailer|
|Max Trailer Weight||30,200||13,700||14,100|
Even though the make and model of these two trucks is the same, separated by just nine years, these numbers show that they are two radically different trucks!
After doing so many test drives, studying all the material and thinking about this truck for two years, there was no way we would give up any of the options we wanted, especially the ones that made the tow ratings and payload rating so high. But we never found a dealership that ordered this exact truck for their lot. Time and again, Mark would find a truck that was close, but there would be some things missing and other things we didn’t want.
So we decided to order the exact truck we wanted and wait 8 weeks for it to be built.
We had a ball ordering this truck through Airpark Dodge in Scottsdale, Arizona, where a marketing connection with Alice Cooper made one of Mark’s lifelong dreams come true. See our really fun blog post:
Once the truck arrived, we installed our very cool new hitch in less than an hour:
A significant difference between our 2007 Dodge Ram truck and our new 2016 Ram dually is that the new truck requires occasional refilling of the DEF (Diesel Exhaust Fluide) tank. Here are some tips we’ve discovered about DEF since we purchased our new truck:
Never miss a post — it’s free!
More info about Pickup Trucks, Ram Trucks, Tow Ratings, etc.:
- 2007 Ram Trucks Towing Guide Our truck: p. 20, 2nd to last line. Search for: “D1 8H42 (SRW)”.
- 2016 Ram Trucks Towing Guide – Ours is on p. 5, 2nd section, last line. Search for: “CREW CAB LONG BOX, 4X4, DRW”
- 2016 Ram Trucks Model Specific Weight Ratings – Set Cab to “Crew” and Drive to “4×4” Ours is the fifth truck in the list. If you know a VIN number, click the red button “Look Up My Vehicle” to get the specs for that truck.
- 2016 Ford Super Duty Towing Specs – Comparable dually truck in 2nd section, 2nd to last line.
- Cummins horsepower/torque info – “Aisin Auto” is the Aisin AS69RC transmission
- Cummins tow ratings – RPMs for peak horsepower and torque
- Cummins horsepower torque specs for all model years 6.7 liter – Quite a progression
- Video – How A Cummins 6.7 Liter Engine Is Made
- Video – Backing up a trailer – A spoof for a laugh
- History and explanation of truck model numbers, weights and payloads – How far we’ve come.
- Escapees Smart Weigh Program for RVs – If you have an RV, do it!
- Ram Trucks tips for How to Tow a Trailer – An excellent illustrated guide
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