Sames goes for the GMC Yukon, but the numbers don't include the new diesel engine.

For the 2021 model year, the Chevrolet Suburban and its shorter Tahoe sibling are new vehicles from the ground up. As such, the upscale GMC Yukon is also new. Not quite as new are the engines powering these full-size SUVs, with the venerable 5.3-liter and 6.2-liter V8s returning under the hood. They aren’t exactly thrifty when it comes to fuel usage, but figures reported by General Motors claim the new models will see very slight improvements in fuel economy for city driving.

In this case, very slight equals a single mpg increase at best. The increase applies to both engines, but in most instances there are trade-offs in highway fuel mileage. These figures are said to be EPA-rated, but it should be noted that as of this article posting in early May, stats for 2021 models haven’t been posted to the EPA’s official mileage website at fueleconomy.gov.

Save Thousands On A New Chevrolet Tahoe
Chevrolet Tahoe
MSRP $ 49,295
MSRP $ 49,295
Save on average over $3,400 off MSRP* with
Motor1.com Car Buying Service

Here’s a specific breakdown showing the mileage differences between the outgoing and incoming Chevrolet models. Equivalent GMC models are said to yield the same results.

Vehicle 2020 MPG (Cty/Hwy/Comb) 2021 MPG (Cty/Hwy/Comb)  Difference (Cty/Hwy/Comb)

Suburban 2WD 5.3L

15/22/18 16/20/18 +1/-2/0

Suburban 4WD 5.3L

14/21/16 15/19/17 +1/-2/+1

Suburban 2WD 6.2L

14/23/17 15/20/17 +1/-3/0

Suburban 4WD 6.2L

14/20/16 14/19/16 0/-1/0

Tahoe 2WD 5.3L

15/22/18 16/20/18 +1/-2/0

Tahoe 4WD 5.3L

15/21/17 16/20/18 +1/-1/+1

Tahoe 2WD 6.2L

14/23/17 15/20/17 +1/-3/0

Tahoe 4WD 6.2L

14/22/17 15/19/16 +1/-3/-1

The increase in city mileage is indeed small and there is a clear determent for highway mileage, but the General’s new full-size people movers are also larger than ever. The Tahoe and Yukon have a wheelbase that’s 4.9-inches longer, with overall length stretched out 6.7 inches. The Suburban and Yukon XL are 1.3 inches longer overall with a 4.1-inch increase to wheelbase.

The result is more space inside for people and things, but there’s also no denying that these vehicles are supreme gas guzzlers that have seen only marginal mileage improvements over the span of two decades. In 2000, a four-wheel-drive Chevrolet Tahoe with the 5.3-liter V8 had a city-MPG rating of 13 with a highway rating of 16, delivering 14 combined mpg. 20 years of development sees the SUV with same displacement V8 managing just 3 to 4 mpg better in all categories.

Fuel mileage statistics for the new 3.0-liter Duramax turbo-diesel inline-six engine haven’t been released. It will likely be the economy king for buyers wanting a big SUV that’s more frugal at the pump.

Gallery: 2021 Chevrolet Suburban, Tahoe