Also, there might be a (rare) steep street that the EV, without low gears to use, just cannot go up.
Consider a 3500 pound car with 500 pounds of passengers and cargo (4000 total) ...
With 400 ft-lbs of torque on the axle, on a 16" rim (approx 1 foot tire radius), that produces 400 pounds of "push" on the road/car, only enough to go up about a 12% grade.
The occasional "really steep" street could be in the 20% (to perhaps 30%) range.
How much torque does the LEAF have at the wheels?
Nissan isn't saying yet, at least on the LEAF site. But here's a wild guess:
They are saying 107 Horsepower and top speed of 88 MPH.
With a 24" wheel diameter, this would be about 1200 wheel rpm
Motor rpm is the wild guess -- 12,000 sounds reasonable
Horsepower = (torque * EngineRpm) /5252
doing the math, I get engine torque of 47 lb-ft
Effective gear reduction is 12,000/1,200 = 10:1
torque at the wheels = 470 lb-ft at maxRPM
At this point, it doesn't matter what the actual engine rpm is, since it's used to factor both torque and the effective gear reduction; any change just cancels out.
But, one can't assume that torque is constant over the rpm range, even with an electric motor. See the power and torque curve for the Tesla
You can see the torque at maxRPM is only about 1/5 that of the low range.
So if we use that value to extrapolate and go even further out on the limb, the low-speed torque at the wheels of the LEAF would be 2350 lb-ft
If my crazy math is right, you'd be ok here:
Edit: -- okay max power on the Tesla example peaks earlier too, so it looks like another factor is necessary for my wild guess. Divide by 2, to get 1175 lb-ft at the wheel for low-speed torque.