Hello there!
In this video I want to show you how to increase the max speed of your Rockrider EST 900! The hack is the same on the EST 520.
You can try on other brands, if the components are the same as this bike.


Remember than you cannot use your bike on public roads and area after this kind of modification.
Use them only in private areas!
I'll not be responsable of unproper use of this modification