A torque spec is the manufacturer's specified tightening value for a fastener, given in ft-lbs or in-lbs, that produces the intended clamp load when the fastener is installed with the specified lubricant and thread condition.
Torque is a proxy for clamp load, not a measurement of it. Most of what the wrench feels is friction, so dry threads, the wrong lube or a rough bolt head all change the preload you actually get from the same reading. ARP calls the lubricant the main factor in friction, notes friction is highest the first time a fastener is tightened, and says common lubes need five to seven install cycles before preload settles. ARP’s published table lists a 1/2-inch fastener in 190,000/200,000 psi material at 125 ft-lbs for roughly 18,515 lbs of preload with ARP Ultra-Torque lube, but states those values are “for general information only, not for specific installations” and that the instructions packaged with the kit always win.
A fastener torqued to the wrong number, or to the right number with the wrong lube, either backs out under vibration or snaps from being stretched past its design.
Read the full post:
Race Car Torque Specs: Which Fasteners Matter and How to Keep Them Tight