If you are new to the truck world because you just got an RV or a boat that will need to be towed, truck shopping can be a little confusing. What affects towing capacity? How is it that two trucks with the same engine have different towing capacities? Why does a smaller engine have a bigger towing capacity? We’ll try to help you understand some of the key factors that affect towing capacity on the Ram 1500 lineup.
The biggest factor out of many factors in a truck’s towing capacity is the engine. Generally speaking, a bigger engine can tow more, but that also depends on the type of fuel the engine uses, such as diesel or gas.
In the case of Ram’s light duty truck lineup, the Ram 1500, there are three different engines and they all have different towing capacities.
The base engine on the lineup is the 3.6-liter Pentastar V6 engine. This engine generates 305 horsepower and 269 lb-ft of torque and has a towing capacity ranging from 4,850 (3.21 axle ratio) to 7,100 pounds (3.55 axle ratio).
Also on the Ram 1500 lineup is the Ram EcoDiesel engine and it is a 3.0-liter EcoDiesel V6 engine. This engine actually has a smaller displacement and produces lower maximum horsepower than the larger 3.6L Pentastar engine, but it produces a lot more torque, 420 lb-ft of torque, and it has a much higher towing capacity ranging from 8,300 pounds (3.55 axle ratio) and 9,300 pounds (3.92 axle ratio).
The reason the 3.0L EcoDiesel is able to tow more is because the engine is a diesel engine and diesel engines produce more torque, and torque is essential when it comes to towing capacity. Additionally, diesel engines burn cleaner and slower, so diesel engines typically have a better fuel economy than a gas-powered truck that is the same size. The Ram EcoDiesel engine gives the Ram 1500 best-in-class fuel economy of 21 mpg in the city and 29 mpg on the highway.
The largest and the most powerful engine on the Ram 1500 lineup is the 5.7-liter HEMI V8 engine and it produces produces 395 horsepower and 410 lb-ft of torque. This engine has a towing capacity ranging from 8,550 pounds (3.21 axle ratio) to 10,700 pounds (3.92 axle ratio).
In addition to engine size, axle ratio is another key component to towing capacity. A truck with a higher axle ratio can produce more torque and acceleration at lower speeds, which is very important when towing.
On the Ram 1500 lineup, there are three available axle ratios – 3.21, 3.55 and 3.92. The base axle ratio on 4×2 gas trucks is 3.21, 4×4 gas trucks is 3.55 and the biggest axle ratio on 4×4 or 4×2 gas trucks is 3.92. The base axle ratio on 4×4 or 4×2 diesel trucks is 3.55 and the biggest axle ratio on 4×4 or 4×2 diesel trucks is 3.92.
As shown in the previous section, larger axle ratios can substantially increase towing capacity. The max towing capacity of a Ram 1500 with a 3.6L Pentastar engine goes from 4,850 pounds with a 3.21 axle ratio to 7,100 pounds with a 3.55 axle ratio — which is almost a 50 percent increase. The percentage increase is not quite as significant with the 5.7L HEMI engine. With the 5.7L HEMI the 3.55 axle ratio provides a 25 percent increase in towing capacity in comparison to the 3.21 axle ratio.
It Is What It Is
Another thing that affects towing capacity is the weight of a truck and all of its parts. The more a truck weighs, the less it will be able to tow because the max towing capacity is what it is and more weight will subtract from the total number.
A truck’s cab size changes the weight of a vehicle. The available cab sizes on the Ram 1500 are the two-door, three-passenger regular cab, four-door, six-passenger quad cab and the bigger, four-door, six-passenger crew cab. Since the crew cab is bigger, it will have the lowest towing capacity of all three cab sizes, but the change is only a fairly small amount ranging from 100-300 pounds.