Home > Maintenance & Mods (L322) > Wheel Hub Mating Face - Don't Grease |
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dan_uk_1984 Member Since: 12 Nov 2008 Location: Bude, Cornwall Posts: 4014 |
Just a reminder, and not wanting to teach anyone to suck eggs:
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3rd Jun 2010 8:56pm |
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dantheman Member Since: 02 Feb 2009 Location: North: Lancs Posts: 477 |
Sorry Dan, lost me there - what shear forces would these be? Could you expand on this please? |
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3rd Jun 2010 10:09pm |
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SteveMFr Site Sponsor Member Since: 22 Nov 2009 Location: Strasbourg, France Posts: 1641 |
Dan means the rotational shear forces. Wheel lugs are designed to work more under compression then shear - and Dan is absolutely correct in stating that it is mainly friction between the flange and the wheel that keep the wheel from rotating on the flange under hard acceleration or heavy braking. The lugs are simply the clamp.
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4th Jun 2010 6:40am |
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SteveMFr Site Sponsor Member Since: 22 Nov 2009 Location: Strasbourg, France Posts: 1641 |
Must - practice - quicker - typing
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4th Jun 2010 6:42am |
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IanV8 Member Since: 14 Jan 2010 Location: Dunfermline Posts: 502 |
That was a good tip.
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4th Jun 2010 8:17am |
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daveo Member Since: 21 Oct 2009 Location: london Posts: 2307 |
hi, thanks dan, like me i did use greese, i was told this years ago to stop alloy wheels sticking to the hub but will be cleaning it off asap... V8 facelift Range Rover Autobiography 22" wheels.
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4th Jun 2010 10:06am |
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dantheman Member Since: 02 Feb 2009 Location: North: Lancs Posts: 477 |
Right: I see where you're going with this now.
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4th Jun 2010 3:19pm |
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Vogue Member Since: 31 Jan 2008 Location: on the hill Posts: 3742 |
I am mystified, if this is so then why is there a stepped / taper on the wheel nuts, its existence will simply transfer the torque directly from the wheel rim onto the hub studs. The shearing force of a vehicle under heavy breaking cannot be retained simply by the friction between two surfaces clamped together.
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4th Jun 2010 3:29pm |
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dantheman Member Since: 02 Feb 2009 Location: North: Lancs Posts: 477 |
Yes - the sunk shoulders locate the wheel centrally to the stud/nut. Don't forget the purchase that the threads give along their pitch additionally. The nuts/studs have to "pull" against something for want of a better word: if you were to unravel a screw thread consider the area in contact with the nut/hole thread.
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4th Jun 2010 7:03pm |
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dan_uk_1984 Member Since: 12 Nov 2008 Location: Bude, Cornwall Posts: 4014 |
You could equate using grease on the mating face to driving with loose wheel nuts. It puts strain on the studs in a direction that they are not designed to have.
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4th Jun 2010 8:43pm |
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dantheman Member Since: 02 Feb 2009 Location: North: Lancs Posts: 477 |
Dan: certainly not implying anything pretentious - or indeed offering merely an opinion. This information is factual, backed up by my experience firstly as an experienced Army Mechanical Engineer and then an Artificer (further studying engineering design, application, materials and metallurgy, science etc).
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4th Jun 2010 10:50pm |
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dan_uk_1984 Member Since: 12 Nov 2008 Location: Bude, Cornwall Posts: 4014 |
Wheel nut and bolts are designed to be tightened up to a specific torque based on both contact surfaces being clean and dry, so by throwing a lubricant into this equation the factory torque value is then too low. You can then of course up the torque to compensate, but then risk stretching the bolts and then having them fail from that. Stuff from tinternet: The joint face between the wheel and hub should remain dry - this face is, effectively, a clutch face transmitting drive and braking torque between the hub and wheel. This torque should be transmitted by the friction, and not by shearing the bolts. |
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5th Jun 2010 8:36am |
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dantheman Member Since: 02 Feb 2009 Location: North: Lancs Posts: 477 |
I can see the point you're trying to make Dan, but to be fair, a thin coat of copperslip is not going to have a nugatory effect on a given torque value for wheel nuts. The same clamping force would be acting between wheel and hub face, meaning there is no need to increase the torque setting.
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5th Jun 2010 12:43pm |
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