GMC Sierra vs Rivian R1T: Specs Compared

Running cost over five years: at the EPA's 15,000-mile-a-year assumption the Rivian R1T burns about $850 of fuel annually against $1,100 for the GMC Sierra. That $250 yearly gap compounds to roughly $1,250 over five years and $2,000 over eight — often more than the price difference between two trims of the same vehicle, and the single largest running-cost line item separating these two.

City and highway economy: the Rivian R1T leads in both cycles — 94 mpg city and 80 mpg highway against 75 and 61 mpg — so its fuel-efficiency advantage holds whether you commute in traffic or cover long highway miles.

Powertrain choice: the GMC Sierra is recorded with 4 distinct engine configurations (SIDI, 3.0, SIDI; FFV), the Rivian R1T with no. Across 274 recorded GMC Sierra configurations and 91 for the Rivian R1T, the wider the engine spread the more the real-world fuel efficiency depends on which version you actually buy, so check the specific model year and drivetrain rather than the headline number.

Drivetrain and class: the GMC Sierra is offered with 4-Wheel Drive, Rear-Wheel Drive, the Rivian R1T with 4-Wheel Drive, Part-time 4-Wheel Drive, All-Wheel Drive. All-wheel drive typically costs one to two mpg combined against the same vehicle in front- or rear-wheel drive, which is worth remembering when the gap between these two is small. The EPA classes them as Standard Pickup Trucks 4WD and Standard Pickup Trucks 4WD respectively — the class drives the interior volume, cargo space and passenger space each one is measured against.