So I took out my torque wrench for the first time in a ongoing while the other day. I looked at it and it was reading about 30 ft-lbs under no load. Do I need to get a new wrench or can I just at 30 to the recommended? ie torquing lugnuts to 100 if recommended is 70? About to put a skidplate on my rally car and don't want it to fall off being undertorqued