The Drive Motor Sizing Tool is the best way to tell. Inputting 1.5Kg-cm, 2 drive wheels, a radius of 1.4375", a speed of 4’ per second, a maximum angle of 10 degrees etc. The torque required is 15 oz-in. The motor you chose has a stall of 15oz-in and would be far from powerful enough. Even if you drop the weight to 0.75Kg, the torque is 7.5oz-in, which is half the motor’s stall. You should be operating at ~1/4 stall.
The choice is yours.
4- 7/8" means 4 inches plus 7/8 inch = 4.875 inches = 12.3825cm
Not quite. You link to a series 40 (0.4" wide) hub, but the wheel is 0.8" wide. You’d need RB-Ban-155 (series 40 hub, 3mm bore, 2-wide = 0.8" wide) and RB-Ban-104 (0.8" wide, 0.5" hex bore).
You’ll see it’s quite a large and heavy wheel for such a small motor…
It’s a “feeling” since calculations rarely take into account the inertia of the wheel itself. Consider making a 3D CAD model of the project (many free 3D CAD software out there). What additional weight do you plan to add?
Yes - that combination looks possible.
When calculating the torque and motor rpm, use the 1m/s speed and total weight of the robot including the 1.4Kg payload. The tool does not factor in a force acting against the motion (as in a sumo competition) so you will need to read the associated Drive Motor Sizing Tutorial and add an additional force acting at the center of the wheel.
So the total weight is 1.5Kg + 0.7Kg? Consider a sumo robot with similar specifications:
Lynxmotion Viper Sumo Kit
Lynxmotion TERMINATOR SUMO ROBOT KIT
Lynxmotion Predator 6 Wheel Sumo Kit (no electronics) SR2-KT
They all use GHM series spur gear motors.