How to increase the dc motor's speed value more than 255 ? a

[MEKACI]

" How to increase the dc motor's speed value more than 255 ? and the frequency value more than MOTOR12_64KH ? thanks "

Hi all,
I have some questions for you :

At my tank project, I am using 4 dc motors and 1 dc motor uses 9V-12V with adafruit motor shield now. The weightness of my tank project is 6kg ;so I felt like these 4 ,9V-12V, dc motors' speed is not enough for a good acceletarion with this (0, 255) speed value at MOTOR12_64KH while we are writing our code at adafruit motor shield.

Thus, how to increase the dc motor's speed value more than 255 ? and the frequency value more than MOTOR12_64KH ? thanks.
If I put a better dc motor which uses more than 12V this speed of 255 speed value will be more efficient, that is to say, I will be able to observe more speed with a better dc motor with same coding ?

And, for a good acceleration to a 6kg tank's to move what kind of dc motor I should use ? I will be glad if you give me some advices ;and answer my above questions, thanks.

[Agent_24]

As far as I know, you can't, 255 will correspond to 100% power.

Sounds like you are being limited by the motors themselves or they do not have enough current to run properly.