Increase input voltage bit by bit, for example, 12.1V, 12.2V, 12.3V, 12.4V... until the motors output your desired speed or torque. Then record the voltage and measure the current and send them to us. We will figure out the real torque and speed requested in your application per your working voltage and working current, then make an evaluation and offer you a gear motor solution to reach your target speed and torque. The methods could be :

1, Adjust the gear ratio.

2, Adjust the motor winding.

3, Strengthen the magnet force.

One method may be enough, or a combination of them is needed. As motor power is adjustable, only to some extent, a more powerful motor would be recommended to you if it is out of its limit.

New gear motor samples would be made for testing after the solution is finalized.