Lug Nuts Too Tight

John T

Active member

Equipment
2017 BX23S
May 5, 2017
741
196
43
under a rock
Looks good.

Are your rear tars filled?

When I installed my spacers I was surprised how damn heavy they were... :eek:

I also put anti-seize on the studs/bolts....
 

torch

Well-known member

Equipment
B7100HSD, B2789, B2550, B4672, 48" cultivator, homemade FEL and Cab
Jun 10, 2016
2,595
838
113
Muskoka, Ont.
I put fluid film on the threads and surface when I put things back together and torqued the bolts to 100 ft. lbs. as stated in the manual.
Unless the manual says otherwise, torque values are understood to be for clean and DRY fasteners. As a rule of thumb, if you are going to apply anti-seize or other lubricant, reduce the specified torque by 5% to avoid over-stressing the threads.
 

John T

Active member

Equipment
2017 BX23S
May 5, 2017
741
196
43
under a rock
Unless the manual says otherwise, torque values are understood to be for clean and DRY fasteners. As a rule of thumb, if you are going to apply anti-seize or other lubricant, reduce the specified torque by 5% to avoid over-stressing the threads.


Not true.


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torch

Well-known member

Equipment
B7100HSD, B2789, B2550, B4672, 48" cultivator, homemade FEL and Cab
Jun 10, 2016
2,595
838
113
Muskoka, Ont.
Not true.
I have been known to be wrong before. And when I am, I appreciate learning where and how I went wrong.

So, please elucidate. Exactly what part of my statement do you consider to be in error? That the torque value refers to clean and dry threads unless otherwise specified? That lubrication increases the load on fasteners at a given torque? That the torque applied should be reduced 5% when threads are lubricated?

Because doing a little internet research suggests that only the last part of my statement is incorrect. It seems that reducing torque 5% may still be significantly overloading the fastener. The correct reduction is apparently 25 to 50%. I refer you to the following:

https://www.antiseize.com/PDFs/torque_specifications.pdf

https://www.engineeringtoolbox.com/torque-lubrication-effects-d_1693.html

https://www.fastenal.com/en/83/torque-calculator

The last one is particularly interesting. My Kubota WSM does not specify if the given table of torque values are for lubricated or dry fasteners. However, comparing the values given to the calculator it becomes clear that the values in the manual must be for clean, dry threads.