I used to work at Les Schwab tires and will say this, Mitsubishi and Isuzu SUVs were notorious for galling and twisting off. That's not to say that people do go nuts with the gun, or lean on the torque wrench way to hard and overshoot. I like to think I was one of the smart ones there.
Stud Fatigue?
- Thread starter CErnst
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Thanks all. I've had good luck in the past leaving feedback on their national page and getting assistance from area manager. I've now bought 3 sets of tires for this vehicle and two sets from another....you'd think they could comp half hour of labor. There are other companies that offer financing on tires to make purchases easier.
Originally Posted By: Shannow
Originally Posted By: LubeLuke
I have had many standard Subaru and Mitsubishi studs fail. To determine the exact cause you would need to send them in for specialised testing, as it is impossible to tell by looking if they were damaged during installatio or removal.
You can tell a LOT from the fracture face.
Beach marks. Cup and cone surfaces at point of final fracture.
Originally Posted By: LubeLuke
I have had many standard Subaru and Mitsubishi studs fail. To determine the exact cause you would need to send them in for specialised testing, as it is impossible to tell by looking if they were damaged during installatio or removal.
You can tell a LOT from the fracture face.
Beach marks. Cup and cone surfaces at point of final fracture.
Never too old for Netflix and Chill with oilBabe.
Originally Posted By: Falken
Me too. I'm old and fat now. Just polishing wine glasses and walks for me, maybe some Netflix.
Originally Posted By: Falken
Me too. I'm old and fat now. Just polishing wine glasses and walks for me, maybe some Netflix.
The 12mm studs on my saturn wagon were snapping on nearly every summer/ winter changeover near the end of its life.
I got it at eight years old and was the only one to touch its tires for the next eleven years. They don't come off for state inspections here.
My lug nuts were open ended and I think salt got in behind them, making the far outer part of the stud corrode or rust-weld to the lug nuts. Plus they creaked, wicked, and I bet the twisty vibration to go with that creakiness lead to lug fatigue.
I hand torqued them, always. Rust on the threads is what I blame. The studs on my wife's HHR are starting to show stress and snap now.
I got it at eight years old and was the only one to touch its tires for the next eleven years. They don't come off for state inspections here.
My lug nuts were open ended and I think salt got in behind them, making the far outer part of the stud corrode or rust-weld to the lug nuts. Plus they creaked, wicked, and I bet the twisty vibration to go with that creakiness lead to lug fatigue.
I hand torqued them, always. Rust on the threads is what I blame. The studs on my wife's HHR are starting to show stress and snap now.
Originally Posted By: A_Harman
Originally Posted By: Shannow
Originally Posted By: LubeLuke
I have had many standard Subaru and Mitsubishi studs fail. To determine the exact cause you would need to send them in for specialised testing, as it is impossible to tell by looking if they were damaged during installatio or removal.
You can tell a LOT from the fracture face.
Beach marks. Cup and cone surfaces at point of final fracture.
What happens when the studs threads are stripped by the nut, but the stud is not broken? This is the most common problem I have personally seen. Although often after the studs threads are ruined, the nut will become stuck. The easiest way for removal then is repeated on/off with an impact wrench until the stud fails.
How can you determine if the failure was from over torqueing the nut, or from excessive load caused by the wheel and tire? It seems as though both would cause the same stretching of the threads.
Originally Posted By: Shannow
Originally Posted By: LubeLuke
I have had many standard Subaru and Mitsubishi studs fail. To determine the exact cause you would need to send them in for specialised testing, as it is impossible to tell by looking if they were damaged during installatio or removal.
You can tell a LOT from the fracture face.
Beach marks. Cup and cone surfaces at point of final fracture.
What happens when the studs threads are stripped by the nut, but the stud is not broken? This is the most common problem I have personally seen. Although often after the studs threads are ruined, the nut will become stuck. The easiest way for removal then is repeated on/off with an impact wrench until the stud fails.
How can you determine if the failure was from over torqueing the nut, or from excessive load caused by the wheel and tire? It seems as though both would cause the same stretching of the threads.
Last edited:
Kestas
Staff member
Barring situations such as curb impact or other such trauma, you cannot get excessive load from the wheel and tire during operation that would stretch the threads. If you do, there is movement in the fastener assembly, which often results in high cycle fatigue fracture. Threaded assemblies are unique in this respect. The fracture would look markedly different than overtorqueing the lug nut.
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