Towing with GMC’s Big EV Models

GMC’s large Ultium-powered EVs, as in both Hummer EV models and the Sierra Denali Edition 1, are full of impressive figures, including extraordinary horsepower and torque figures. Towing is an expectation for the gas-powered equivalents of these vehicles, so the question arises as to how capable these EVs are at towing. The short answer is that each has a maximum towing capacity of 10,000 pounds, but the Dieffenbach GM Superstore offers a more detailed answer.

Impressive Electric Power

Let’s start by looking at the Hummer EV SUV. At the middle of the model line, the 3X is rated as having 1000 horsepower. GMC hasn’t published the torque, but Motor Trend estimated a figure of 1,045 lb-ft. Because these are electric motors, all that torque is on hand from when the motors start moving. That abundant accessible torque contributes to the Hummer EV SUV 3X’s maximum tow rating of 10,000 pounds.

The GMC Sierra EV Denali Edition power figures are slightly smaller yet still impressive at 754 horsepower and 785 lb-ft of torque. That is higher than any Sierra 1500 gas engine while falling short of the 6.6-liter Duramax turbo-diesel with 975 lb-ft of torque you find on the Sierra HD. The Sierra EV is also rated to have a 10,000-pound maximum towing capacity. For those who head toward the mountains, it Is worth noting that in contrast to gas and diesel engines, atmospheric pressure changes do not impact electric motors. So, the Hummer and Sierra EVs will be as powerful on the mountaintop as alongside an ocean beach.

Instant Electronic Response Improves Stability

Power isn’t the whole story when it comes to towing. Stability is another key factor, but this also brings up an EV advantage, particularly the three-motor system. With an electric motor powering each rear wheel, the motors can adjust their individual power output instantaneously in response to potential swaying conditions created by the trailer, including during adverse weather or an uneven surface.

The Hummer SUV and Sierra EV include a towing assistance package with a driving mode specifically for towing that optimizes all systems for the task. The package also includes an air suspension, which keeps the vehicle level regardless of cabin or trailer load. The package features a rearview camera system with a clear view of the hitch area and trailer guidelines to simplify hitching. The blind-spot monitoring system can extend to cover the length of the trailer, enhancing situational awareness for safer lane changes and turns.

Range While Towing

The subject changes from how much to how far. While both gas and diesel-powered vehicles also have significantly reduced range when towing, the impact is more significant for EVs.  Ironically, this is due to their efficiency.  Gas has been the energy source for our vehicles because it is so dense in energy.  So much so that the Sierra EV’s relatively huge 205 kWh battery stores about the same amount of energy as six gallons of gas. And yet, it can travel approximately 400 miles from that. This is because, despite all the improvements in fuel efficiency over the past 50 years, gas engines are only about 20 – 30% energy efficient.  That is to say, for every dollar you spend on gas, only 20- 30 cents worth actually moves the vehicle. The rest is mainly lost to heat and mechanical drag from the transmission and the rest of the drivetrain.  EVs, on the other hand, are 80-90% energy efficient.  So, for every dollar spent on electricity, 80-90 cents goes to moving the vehicle.

Trailers are a triple whammy when it comes to efficiency.  They add weight, rolling resistance, and aerodynamic drag. The trailer will add the same loss of efficiency for gas or battery-powered vehicles. It just adds a bit to the massive inefficiency gas engines already have for which they contain big tanks of energy-rich gasoline to accommodate.  For EVs, however, the trailer adds a large amount of inefficiency to a very efficient system; thus, the impact is more significant.  Consequently, an EV can still tow a trailer more efficiently than an equivalent gas-powered truck, but the range is more impacted.

Consumer Reports tested the range of EV vehicles while towing. The test did not include any of GMC’s models, but when towing a 10,000-pound trailer, the Ford F-150 Lightning and Rivian R1T range dropped to about a third of their normal range. The more powerful Sierra EV and Hummer SUV may not be as impacted, and this is a worst-case scenario with the maximum trailer weight. Lighter trailers can be expected to have a smaller drop in range.

Fortunately, the GMC models also benefit from an 800-volt electrical architecture that allows much faster charging than most other EVs. A 350 kW fast charger can charge these models up to 100 miles in 10 minutes. With towing, that figure could come down to 40 – 60 miles per 10 minutes, depending on the trailer weight.

To sum up, if you have a favorite place not far from home to which you like to bring a boat, camper, or toybox, any of GMC’s EVs could be the most competent towing vehicle you have ever had and have 100% emission-free operation while they are at it. Longer trips require planning for recharging. As often is the case, the attractiveness of EVs depends entirely on how you use them.

To see how the Sierra EV or Hummer EV can fit your life, visit the Dieffenbach GM Superstore and test drive these sophisticated EV models for yourself.