Lug nuts on wheels
Lug nuts on wheels
(OP)
Does anyone know what the mechanisms are used to keep the lug nuts from backing out from the wheel?
This was after a discussion. I thought that it might be the centripetal motion of the wheel that causes a torgue on the nuts that drive it into the car. Someone else said that lug nuts are usually rounded or tapered and so are the the wheels, this causes increased surface area and thus increased frictional force that help the nuts from backing out.
This was after a discussion. I thought that it might be the centripetal motion of the wheel that causes a torgue on the nuts that drive it into the car. Someone else said that lug nuts are usually rounded or tapered and so are the the wheels, this causes increased surface area and thus increased frictional force that help the nuts from backing out.





RE: Lug nuts on wheels
The mechanism that prevents this on a wheel joint is the same as it is for any threaded fastener joint: frictional forces between the contact surfaces of the fasteners and the clamped members. The frictional forces are the result of preload.
Modern automobile wheel joints use either conical or spherical contact surfaces between the lug nut and wheel. The use of these nonplanar contact surfaces removes play between the wheel and hub, and allows shear force transfer between the wheel and hub in the absence of preload, which is for enhanced safety.
This joint is one of the few safety-critical joints that an end user actually loosens and retightens, and with the large variations present in threaded fastener joints, it is important to provide a larger operating envelope.
Regards,
Cory
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RE: Lug nuts on wheels
Regards,
Lyle
RE: Lug nuts on wheels
truck wheels have a maintenance re-torquing schedule. Gotta think if the studs were 6 diameters long they would have enough spring action to maintain torque even on the solid wheels
RE: Lug nuts on wheels
If I rememeber my college classes right, stretching the bolt generates a HUGE!!! clamping force and most of the force that is resistant to "backing off" is in the threads - friction - which is why you will see much discussion about the use of oil and antiseize compounds on torgued bolt threads.
RE: Lug nuts on wheels
Apologies and regards,
Lyle