Just realized I was torquing lug nuts way too tight for 8 years after a wheel stud snapped on a 2015 F-150 at 60 mph on I-35.

A guy at the shop showed me the spec sheet and I'd been going 150 ft-lbs on everything instead of reading the actual torque sequence.

3 comments

3 Comments

mary_kelly2mo agoTop Commenter

150 ft-lbs is barely more than what the spec is for a lot of those trucks anyway. A stud snapping at 60 mph sounds like a bad part or improper thread engagement, not your torque wrench. If anything, you were probably keeping those wheels on tighter than the factory ever intended, which is a good thing for safety on the highway. Guys who follow the exact spec on paper end up with loose wheels and vibration complaints more often than not. Keep going tight and just buy better studs.

wesley_fox922mo ago

So are we saying the factory engineers are just guessing with those torque specs? Ngl, @kelly968 your buddy's F-250 story is exactly why I'd rather trust the data than just crank it down until it feels right. Mary, I get what you're saying about loose wheels being a pain, but a snapped stud at speed is a whole different level of bad. Honestly, stretching those studs past their yield point isn't a gamble I'd take just to avoid a little vibration. I'd rather snug them to spec with a good torque wrench than be the guy picking a wheel up off the shoulder.

kelly9682mo ago

Kelly I get what you're saying but I have to hard disagree here. My buddy's F-250 had a stud snap on him doing 70 on the interstate because he was torquing them to 160 ft-lbs thinking the same thing. That wheel came off and folded his rear fender like paper. I've seen the data from Ford engineers that say going over 140 ft-lbs on those stock M14 studs actually stretches them past their yield point and makes them brittle over time. You're not wrong that loose wheels cause vibration, but overtightening causes fatigue cracking that you can't see until it's too late. The factory spec exists for a reason, and it's usually based on the weakest link in the system which is the stud itself not the nut. Better to buy a quality torque wrench and use it every time than gamble on "tight enough" when you're talking about 6000 pounds of steel rolling down the road at highway speed.