The effect of forward CG is to increase tail-down force, main-wing loading, and the stalling speed. ... As the CG moves rearward, less tail-down force is required and the stalling speed decreases. However, moving a CG too far aft reduces pitch stability.

Why does a forward CG have a higher stall speed?

The only way to continue level flight is to increase angle of attack in order to increase lift – that means that for the same aircraft weight, a forward C.G. will cause you to fly at a higher angle of attack and thus closer to the critical angle of attack, and therefore you increase the stall speed.

How does aft CG affect performance?

Aft CG. The relationship between your aircraft's performance and CG location is simple: by moving your CG forward and aft, you change the amount of tail down force and lift you need for stable flight. When you create more lift, you create more induced drag, and your performance goes down.