Relatively long story short, I got some new tires put on my Outlander (Destination LE2). When taking off the rear wheel, three of the studs twisted off. The last person to touch the wheel was that shop when I had them rotate and do an alignment about a month ago. Shop swore up and down that the studs broke from fatigue. I have a really hard time buying this story...I think they cross-threaded them and they twisted off removing the lug nuts. They ended up comping me cost of the studs and lug nuts, but stuck me with 1/2 hour of labor. I'd really like to get your thoughts on this.
Stud Fatigue?
- Thread starter CErnst
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#1 reason not to let other people touch your cars private parts
classic case of wheel stud being "gunned" by air impact gun in the past, which over-torqued the studs (stretched).
Given in time: these "gunned"(overtorqued) studs will stretch and fail, one by one.
Only by means of cutting the loss (and pain) and have all of them re-studded with fresh new ones and then all of them torqued (wheels mounted of course) to factory specifications (threads dry of course) will you be able to get the peace of mind that they (studs, wheels) will not fall off on you.
seen this happened so many times in the past. Nowadays, with most tire shops using air-impact gun + torque sticks (assuming that they used the correct torque spec ones), that this problem is no longer a common occurance.
Q.
Given in time: these "gunned"(overtorqued) studs will stretch and fail, one by one.
Only by means of cutting the loss (and pain) and have all of them re-studded with fresh new ones and then all of them torqued (wheels mounted of course) to factory specifications (threads dry of course) will you be able to get the peace of mind that they (studs, wheels) will not fall off on you.
seen this happened so many times in the past. Nowadays, with most tire shops using air-impact gun + torque sticks (assuming that they used the correct torque spec ones), that this problem is no longer a common occurance.
Q.
Not unusual for the OEM studs to fail. Whether from wear or fatigue is not known.
This is probably the main reason (above strength) that race vehicles replace their studs. Repeated running of the OEM studs causes failure.
You will find many low running rally teams have replaced their wheel studs with aftermarket studs.
Search for Subaru BRZ and Toyota 86 wheel stud failures. Many have reports of repeated failures when wheels are changed often such as for regular 'track day' use. Many claim to have used torque wrenches with the correct torque since new.
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.
This is probably the main reason (above strength) that race vehicles replace their studs. Repeated running of the OEM studs causes failure.
You will find many low running rally teams have replaced their wheel studs with aftermarket studs.
Search for Subaru BRZ and Toyota 86 wheel stud failures. Many have reports of repeated failures when wheels are changed often such as for regular 'track day' use. Many claim to have used torque wrenches with the correct torque since new.
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.
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Originally Posted By: Kuato
I've been changing my own tires since the mid 80s. No matter how badly rusted, never had one stud break. Shop's fault.
I never had problems with the taxis, but with frequent wheel removal, of course, that precludes a lot of rusting.
I've been changing my own tires since the mid 80s. No matter how badly rusted, never had one stud break. Shop's fault.
I never had problems with the taxis, but with frequent wheel removal, of course, that precludes a lot of rusting.
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.
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.
On the stretched stud the pitch has altered, the impact gun friction welds nut to stud and off it comes.
Studs fail when overtorqued and stretched. Original studs in the 4Runner at over 260,000 miles. Frequent tire rotations, tires off many times for brake and other service...so figure 100 times they've been loosened and tightened?
Never one failure.
Never one failure.
I think this was caused by the previous shop. They overtorqued the lugnuts, and when the current shop tried to take them off, the studs broke. I think the current shop was gracious to pay for the cost of the new studs.
Yes I have been tired lately
Me too. I'm old and fat now. Just polishing wine glasses and walks for me, maybe some Netflix.
Id agree that most shops overtorque like crazy. I would agree with Capri, most likely last shop overtightened.
Kestas
Staff member
You don't get fatigue on threaded fastener assemblies unless there is movement in the assembly during use. A properly torqued assembly will hold fast and not move.
I agree with Shannow that it takes a trained eye from a professional to determine whether wheel stud fracture is from fatigue or overload. Humbleness aside, I get paid good money to make these determinations, including wheel studs in particular. I believe Shannow is qualified as well.
I agree with Shannow that it takes a trained eye from a professional to determine whether wheel stud fracture is from fatigue or overload. Humbleness aside, I get paid good money to make these determinations, including wheel studs in particular. I believe Shannow is qualified as well.
You need a new tire store. If you go to the same tire store, then it's them that has done it.
Second, if they didn't overtorque, then they are just making an excuse for cross threading, and they need to come clean and fix it for free.
Last year Discount Tire couldn't get a nut off of one of my wheels. They recognized that they do all my tire care, so they gave me a voucher to get a new stud put in at a local shop. They told me that they had had an employee that didn't follow the hand start policy, but he is no longer with Discount Tire.
That's the way your shop should treat you.
Second, if they didn't overtorque, then they are just making an excuse for cross threading, and they need to come clean and fix it for free.
Last year Discount Tire couldn't get a nut off of one of my wheels. They recognized that they do all my tire care, so they gave me a voucher to get a new stud put in at a local shop. They told me that they had had an employee that didn't follow the hand start policy, but he is no longer with Discount Tire.
That's the way your shop should treat you.
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Originally Posted By: Garak
Originally Posted By: Kuato
I've been changing my own tires since the mid 80s. No matter how badly rusted, never had one stud break. Shop's fault.
I never had problems with the taxis, but with frequent wheel removal, of course, that precludes a lot of rusting.
Perhaps I should have said, "regardless of the state of rust or not"....
Originally Posted By: Kuato
I've been changing my own tires since the mid 80s. No matter how badly rusted, never had one stud break. Shop's fault.
I never had problems with the taxis, but with frequent wheel removal, of course, that precludes a lot of rusting.
Perhaps I should have said, "regardless of the state of rust or not"....
It depends on the vehicle. I still swear that my Prius has the world's weakest lug studs -- torque sticks and/or hand tightening for the last 116k still results in a broken stud periodically.
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