There is no need for a 'transmission' in the design of an electric vehicle since the motor can be speed governed by electronics, so you need to change you traditional thinking and remove any concepts for these technologies when designing an electric vehicle :
* transmission
* carburetor or fuel injector
* gasoline or diesel fuel tank
* fuel pump
* exhaust system 9including mufflers)
* cylinder heads
* engine block
* water pump
* oil pump
* exhaust gas re-circulation (ERG - part of emissions)
* emissions systems
* air cleaner
* throttle body
* choke plate or air throttle plate
* intake manifold
* belt driven power steering pump
* alternator
* starter

The fact is that for electric vehicles , there will be a 40% to 50% reduction in parts since there are fewer and simpler, but different elements to the design.

Part of the core focus will be on these major components :
* battery system
* charging system
* battery monitoring
* battery protection
* electric motor(s) [ induction, AC, VFD, PM-DC)
* high voltage cables
* regenerative brakes
* electric steering pump

You can use the formula

r = B / [ (1/n) (m*g*Crr + 0.5 * rho * Cd *A * v^2) + P/v ]

Dimensionally:
km = km/h * Wh / W
h and W simplify and therefore the calculations add up.

But where does this formula come from?

B = Battery Wh
n = mechanical efficiency (between 0 and 1)

F = m*c*Crr = Rolling friction force of the wheels
m = half mass
g = acceleration of gravity = 9.81 m/s^2
Crr = coefficient of friction (around 0.01)

F = 0.5 rho Cd A v^2 = Air friction force
rho = air density = 1.225 kg/m3
Cd = air friction coefficient (=0.3 for cars, 0.9 for scooters)
A = frontal area (2.2 m^2 for cars, 0.9 for scooters)
v= speed in m/s

P = power of auxiliary devices: headlights, dashboard, control unit,...

Starting from the concept that capacity divided by power = autonomy in hours:

Wh/W = h

and if I multiply the hours of autonomy by the speed in km/h I obtain the km:

km = h * km/h

we get:

autonomy (km) = km/h * Wh / W

Meaning what:

r= v * B / P