At 70mph most of your battery energy is going to pushing around air. There are two ways to help reduce that effect.
- Drive slower.
- Change the shape of the vehicle like this guy: https://www.aerocivic.com/
Well, I guess there's a third option. Sell the crossover and get something more aerodynamic like a sedan or an Aptera.
Tires might help some. But will it be enough?