Are you sure that your nuts are exactly tight enough or are they just loosening with great force? Then use a pneumatic impact wrench. This key from Ferm has a working pressure of 6.3 bar and an unloaded speed of 7,000 revolutions per minute. This allows you to work with a maximum torque of 320 Nm. The key comes complete with a 10-piece socket set and a handy carrying case.