This thesis work was about finding a weight compensation for a crane on a forwarder. The weight compensation had a purpose of reducing the need of lift from the cylinder lifting the main arm on the crane as well as the second arm on the crane. Three different solutions for the main arm was analysed. This resulted in a solution with a variable force applied from a spring.  The second arm was analysed but no final construction could be found. This means that the primary goal was met but not the secondary goal of this project.