Direct drive ( motor to wheel directly)

[1810]

What are of the advantages and disadvantages of connecting wheels directly to motor? I am thinking to connect 600rpm directly to 3.25 or 4in wheel and drive at a reduced rpm via code?

[Brayden21510R]

Reducing the speed in the code causes you to just lose wattage, meaning you’ll drive slower, but not gain the additional torque a gear ratio would give you. So running 600 on 3.25 or 4 would have awful acceleration, equivalent to running it at max speed.

[some.person]

Decreasing RPM in code reduces power as well. Gear ratios retain the full power of the motor while still decreasing the RPM, which allows you to have full torque.

[Gigahertz.t]

As @Brayden21510R said, connecting a 600 rpm motor to any wheel size >2.75" will result in pretty insane speeds, and insanely awful torque.
Reducing the speed via code does nothing to affect the torque (which affects acceleration and pushing power). Your drivetrain will have roughly the same acceleration and pushing power (which are awful for such a speedy gear ratio) as if it were at full speed.

I recently made a post about the difference between reducing the speed via code and using different gear ratios:

Difference between gear ratios and lowering rpm via code

Short Answer / TL:DR Gear ratios change the limits of the motor’s output - the maximum speed and the maximum torque. Coding for rpm changes just changes the speed of the motor, given that it is within bounds of the current gear ratio’s maximum speed. We use both all the time - I for example use gear ratios to lower the maximum output speed of 600 rpm motors to 450 rpm and increase the maximum torque for fun things like acceleration and pushing robots, and in the code I change the rpm of the mo…

[1810]

This is very helpful. Thanks.