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Discussion Starter · #1 · (Edited)
Something I have been waiting for, Rivian has explained their aerodynamic strategy, and unveiled an impressive .30 Cd, which is very impressive. Elon Musk had previously said Cybertruck with a lot of work might reach a similar Cd. I assume Hummer EV will have .38-.42 Cd, which with the larger frontal area, and extra weight will pit it at a decided disadvantage in highway efficiency and as speed increases, it will just get ugly. Hummer 350 miles of range and Rivian at 316 miles EPA, should equal out at 75 mph...

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Depends on tires also, but that is more of a constant due to rolling friction, not a function of dynamic pressure. Rivian has indicated a 10%-15% reduction in range for the 20 inch A/T tires. I assume Hummer 350 miles will be with the standard A/T tires. Rivian did come in a 6949 lb curb weight, which I believe was higher than originally predicted.

Highway range for R1T with 21 inch tires is 293, with A/Ts would be 250-264 with the 20 inch A/T tires.
 

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Discussion Starter · #3 ·
Depends on tires also, but that is more of a constant due to rolling friction, not a function of dynamic pressure. Rivian has indicated a 10%-15% reduction in range for the 20 inch A/T tires. I assume Hummer 350 miles will be with the standard A/T tires. Rivian did come in a 6949 lb curb weight, which I believe was higher than originally predicted.

Highway range for R1T with 21 inch tires is 293, with A/Ts would be 250-264 with the 20 inch A/T tires.
Over 40 mph or above aerodynamic drag is the the biggest force acting against the vehicle, even the weight has little bearing once up to speed. The Hummer has a much worse, Cd, and larger frontal area, therefore much more total drag.

Remember too, the Rivian has a FWD mode for Range which the EPA test averages out, Hummer does not have this, so more drivetrain drag also at high speed. Off roading or in town the Rivian will be far more efficient just due to mass. Hummer has 65 kWh more battery and will need all of it. I am expecting Hummer MPGE to be just around 50, we will soon know, my buddy is driving the Hummer EV today... :)
 

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