I had posted this on another thread, but thought it merited it's own thread, so here it is again.
I just found this site:http://www.derose.net/steve/resources/engtables/bolts.html#largebolts
Of course, the charts are just values calculated using industry accepted formula T = KDP where T = Torque (inch-lb.), K = torque coefficient (dimensionless), D = nominal diameter (inches), P = bolt clamp load, lb.
K values vary depending on the surface: waxed (e.g. pressure wax as supplied on high strength nuts) = .10, hot dip galvanized = .25, and plain non-plated bolts (as received) = .20.
Torque has been converted into ft/lbs by dividing the result of the formula by 12
( I didn't verify all the numbers, but some of the ones I checked seemed off (the 7/8 bolt chart seems to be copied from the ¾ chart, so use at your own risk. )
The clamp load = 0.75 ( proof load / stress area )
(the proof load is about 80% of the tensile strength)
The clamp load of a 3/4"-16 gr8 at 419 ft-lbs is 33,566 lbs! - Helps explain how easy it is to warp the hub or distort the tapered seat in the rim with that much pressure. . .
Over torquing a bolt loads it closer to its breaking point - Helps explain why some studs pop off. . .
I hope this helps.