How do I know what flex is right for me?

The correct flex is determined by your body weight and skiing style. The ski must compress enough under your full body weight to engage the grip zone during the kick, but remain uncompressed when you're gliding with weight on both skis. The best way to find the right flex is to visit a specialty Nordic shop that uses a flex board—a tool that measures how the ski bends under specific weights. If you can't access a flex board, use manufacturer weight recommendations as a guide, but be aware that these are approximate and individual technique affects the ideal flex.