johnlocke wrote:CD isn't everything. CD X Cross Section = Drag. I wonder why no one publishes their cross section numbers or total drag at a given speed ( 60m/h)?
Correct, but Cd is commonly accepted criteria when comparing. That is all we have or they disclose to us. It is still the most important parameter of overall aerodynamic design. The Cross Section comes in play when modifications are made to increase or reduce standard configuration cross section. Like upgrading 16-to-17 tires - would increase cross section, downgrading 16-to-15 will reduce it and etc. Some folks may find it difficult to understand because of they think the tire outer diameter stays almost the same. The inefficiency drop comes from the fact you have to put wider tires to compensate for side wall height reduction and it increases cross section. It is the most critical though in EV as range takes way more time to extend by more frequent re-charging unlike in ICE. That is when I see EV adaptation of the existing ICE car it is just failure from the get go. Only good for city driving, forget about highways.
I needed no proof of poor aerodynamics of Leaf once I got it above 55 mph - that is pretty much the end of the range, get ready to half it. And God forbid to have a head wind, butt wind helps a bit. Nothing wrong with Leaf, I think it was design for city dwellers and it is pretty good at it. But as they put bigger and bigger batteries I am not sure what they are trying to achieve - it would never be reasonable on the highway without major redesign and this is where long range matters. Perhaps, they think of Taxi in the city to consume this range at relatively low speeds.