Using this axle is straightforward. First, make sure your go - kart is turned off and cooled down. Then, carefully remove the old axle and install the new F. Tony Kart OTK 50mm axle in its place. When selecting the hardness, think about your driving style and the track conditions. For smoother tracks, a softer axle might work well, while for more aggressive driving or rougher tracks, a harder axle is a better choice. As for maintenance, regularly check the axle for any signs of wear and tear, like cracks or excessive rust. Clean it with a mild soap and water solution and dry it thoroughly. Lubricate the moving parts as needed to keep it running smoothly. If you notice any problems, replace the axle promptly to ensure your safety and the performance of your go - kart.