Once upon a time, Vince posted that he goes more, around 90. I responded to that post stating I do the factory recommendation, however, that was until I had some wheels refinished and almost lost a wheel. Yes, for my factory wheels on my 98, I've used the factory standard with no issues. When I spoke with a tech after nearly losing a wheel on a 95, the tech said use 90. Apologies to Vince - he is right. Although I've had not problems on factory wheels, the value is very low. I now use 90 Ft-lbs as my standard.
I always re-torque refinished or new wheels after a short drive. It seems that they need a bit of driving to "settle-in" i.e. the paint layer to be displaced/compressed at the clamping surfaces, both of which can cause loss of torque in the bolts.
My situation was crazy. Drove out less than 10 miles. On the way home, a mile from my house the back end started getting unstable. I slowed down and limped home. Got in the driveway and all the rear bolts were loose. The idiot who refinished the wheels put so much material on that the heat melted it on the matting face causing the bolts to come loose. I'm Luck to be alive and the car not damaged. I cleaned all the paint off the matting faces and all was well.
With a new set of wheels on the team, we'd run the center nut on and off a bunch of times, then clean out any paint residue. With a single center nut, not only do the mating surfaces have to be clean, but having a marred surface helps. sjd
I had myne set at 72 lb-ft when a Ferrari mechanic at an HPDE retorqued them to 90 lb-ft for the event. Certainly the nut and threads can take this kind of TQ.
Same thing happened to me at a Ferrari event. When I pulled the wheels some time later I found a few cracked inserts that needed replacement.
90 ft lbs won't break your inserts. 90 ft lbs for an M14 is nothing. I'd bet the inserts where not properly seated in the wheel.
I believe that the torque limitation for the wheel bolts is not the strength of the bolt (it can take some 150 lb.ft if Grade 10.9) but the strength of the wheel hole (or the insert) to withstand the radial force created by the taper of the bolt. If the bolt is overtightened, it can spread-out the insert too much and crack it.
Only if not backed up buy the rim, hence a gap between the two. I believe that is the reason they break.
I actually backed down my torque to 80 lb. ft. I think that 90 stretches the threads too much. But 70-75 lb. ft. is not enough, IMO.
I also recommend 80ft/lb. Test drive the car and then recheck. You can feel that torquing the lug bolts any more than that does not cause them to move. 90 ft/lb is a little too high for my comfort level, especially on 355 wheels with the inserts.
