Top speed at electric cars
Cars with ICE internal combustion engines are designed, that in the 4th or 5th gear is the maximal engine power reached at top speed.
After this, the transmission ratio for enough uphill performance is determined. This is the transmission ration of the 1st gear. In between are as harmonic as possible the other gears.
At modern 6 gears gearing is a range of 5:1 from the 1st to the 6th gear usual. When the car can reach 200 km/h in the 6th gear, it's only 40 km/h in the 1st gear.
Only very few electric cars have gears. At the Tesla, 2 gears had been planned, but they have later decided different for the serial production. The transmission ratio is out of this reason designed like the 1st gear for a car with ICE: enough uphill performance.
So for everybody wailing, that the Tesla has only 200 km/h and the BYD E6 has only 140 km/h top speed, this is the top speed in the 1st gear and there is no other gear.