Originally Posted by
Bikesplendor
Can anyone answer this: Why are lug nuts supposed to remain ungreased? After all, they aren't different in any fundamental way. They are threaded fasteners, quite similar to the rest. They are designed to clamp and hold and not loosen with use. In other words they perform the same function. And they need to meet the same basic requirements. So why do they recommend not greasing them? They could just adjust the torque specs accordingly....
...I have always assumed that because lubricating the threads changes the torque values you need to apply, the makers decided that in most cases (including initial factory assembly) the person working on them would not take the time and trouble to lubricate them. So they give you a higher torque value (dry torque). That way, you won't have people assembling wheels and hubs with too little torque if they're dry....which is probably more dangerous than too much torque if they're lubricated.
Nobody wants to take credit for a catastrophic failure if someone driving along loses a wheel.
But I also assume the practice might lead to some galling and earlier thread failure........again an assumption on my part.