Wheel lug nuts were tighten too much
#1
Pit Crew
Thread Starter
Wheel lug nuts were tighten too much
After the advise of a friend I bought a CDI torque wrench to re-torque the wheel nuts to spec - he said even dealers are careless about that. With the new tool I realized that the dealer indeed torque too much, about ~100 ft lbs, while the spec says only 76 ft lbs. I had the car serviced at 5k miles, and now it already has 7k on it, so I've been driving the past 2k miles with the wrong torque on 4 wheels! Could my disc brakes be warped already - can I tell? Should I still retorque it at the correct 76 ft lbs now? Thanks.
#3
Pit Crew
It continues to amaze me that dealers and independent shops alike pay so little attention to proper lugnut torque,
As you may know, torque determines how much a fastener stretches, thus holding everything tight. If a fastener is severely overtorqued, the lug or bolt will permanently deform and will not be able to achieve its designed holding ability.
100 isn't too high for lug nuts/studs, even with a 76 spec.. What's more important in this case is whether they are evenly torqued - you get brake disc runout when they are unevenly torqued.
Depending on the type of torque wrench (beam, dial, click, digital) it is really difficult to determine what a fastener has been torqued to after the fact. I almost always retorque mine after any wheel has been removed and reinstalled, by loosening then tightening to the specified torque.
That said, your dealer does thousands of wheel rotations - if they were screwing up Lexi daily they would stop doing it, so I wouldn't worry too much about it. You could make a comment at the 10k or whatever your next service is.
As you may know, torque determines how much a fastener stretches, thus holding everything tight. If a fastener is severely overtorqued, the lug or bolt will permanently deform and will not be able to achieve its designed holding ability.
100 isn't too high for lug nuts/studs, even with a 76 spec.. What's more important in this case is whether they are evenly torqued - you get brake disc runout when they are unevenly torqued.
Depending on the type of torque wrench (beam, dial, click, digital) it is really difficult to determine what a fastener has been torqued to after the fact. I almost always retorque mine after any wheel has been removed and reinstalled, by loosening then tightening to the specified torque.
That said, your dealer does thousands of wheel rotations - if they were screwing up Lexi daily they would stop doing it, so I wouldn't worry too much about it. You could make a comment at the 10k or whatever your next service is.
#4
Instructor
Our '11 CPO RX locking lug nuts were so severely over-torqued at the dealer's, that American Tire couldn't get them off. Dealer replaced locking with standard at my request, no charge. I could watch American Tire using torque wrenches upon tire installation. No deformation of discs, thank goodness.
#6
Lexus Test Driver
How did you determine the lugs were at 100ft/lbs?
Keep in mind, it takes more force to remove a lug nut that it does to install one.
I wouldn't worry about the rotors being warped as long as all the lug nuts were over-tightned equally.
Keep in mind, it takes more force to remove a lug nut that it does to install one.
I wouldn't worry about the rotors being warped as long as all the lug nuts were over-tightned equally.
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#8
Instructor
I wondered about that too. What causes the removal torque to be higher than the install torque? Do the lug nuts "settle in" or something like that?
#9
Instructor
After the advise of a friend I bought a CDI torque wrench to re-torque the wheel nuts to spec - he said even dealers are careless about that. With the new tool I realized that the dealer indeed torque too much, about ~100 ft lbs, while the spec says only 76 ft lbs. I had the car serviced at 5k miles, and now it already has 7k on it, so I've been driving the past 2k miles with the wrong torque on 4 wheels! Could my disc brakes be warped already - can I tell? Should I still retorque it at the correct 76 ft lbs now? Thanks.
If it's the dial type, no problem. If it's the click type, did you reset the clicker to 100 then try removing the nuts? I could be wrong, but I think clicking torque wrenches only work in one direction, ON. Please let us know how you came to the 100 ft lb figure. I think you were removing the lug nuts with the torque wrench and had to go significantly past the 76 lb click and guestimated the 100 lbs.
Comments below video at YouTube site are helpful too.
#10
Pit Crew
Thread Starter
Thanks, I guessed it was 100 ft lbs because I tried to tighten it more, and with 80, 90 settings the torque wrench clicked right away. For two lugnuts, I could move a bit with 100 ft lbs before it clicked, the other 2 - no (I didn't try the one with the lock). I worried and stopped right there to ask
#11
Instructor
The physics of materials heating/cooling cycles over time is one of the primary factors as to why loosening a threaded item takes more torque than when it was originally tightened.
#13
Instructor
#14
Instructor
#15
Instructor
Thanks, I guessed it was 100 ft lbs because I tried to tighten it more, and with 80, 90 settings the torque wrench clicked right away. For two lugnuts, I could move a bit with 100 ft lbs before it clicked, the other 2 - no (I didn't try the one with the lock). I worried and stopped right there to ask
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