Date:         Fri, 19 Jul 2002 19:45:28 -0400
Reply-To:     Ed McLean <email99@BELLSOUTH.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Ed McLean <email99@BELLSOUTH.NET>
Subject:      Lug Nut Tightening Comments (long)
Content-Type: text/plain; charset=us-ascii

With all the discussion on lug nuts and impact wrenches I would like add
a few comments of my own:

1.      When I buy tires or have them rotated I insist a torque wrench
be used to insure the lug nuts are tightened correctly.  I also ask what
torque specifications will be used.  Most tire stores have specification
books and many times the torque specs are also written right on the
wheel bearing dust cover, wheel or brake disc.  If torque specifications
are not followed, loose wheels, frozen lug nuts, stripped lug nuts,
rounded off lug nuts, and broken lug bolts may occur.

2.      I always watch the technician actually install the wheels to
make sure he knows how to use the torque wrench.  I once watched a kid
carefully install the lug nuts by hand, tighten the nuts with a click
type torque wrench until it "clicked", and then give it an additional
healthy tug to make sure they were tight.  He was trying but he just
didn't have a clue.

3.      If the technician doesn't install the lug nuts in the correct
manner I report to the person who wrote the service order and request
that the lug nuts/bolts be hand torqued correctly.  If he will not have
them torqued properly, I won't pay.  It was part of the deal.

4.      Most all chain tire stores have poster that indicated the
correct way to install lug nuts.  Just ask the sales person to explain
it to you.  Then ask him to make sure the technician follows the
directions exactly.  (This also works to insure the tire mounter uses
the proper lubrication when pulling the tire over the rim.  This is
important with tires with stiff or reinforced side walls, such as the
MXL's or light truck tires.)

5.      Some tire stores use a calibrated "Torque Stick" to install lug
nuts.  These are not designed for final tightening but to insure lug
nuts are not over tightened before they are given their final torque
check with a torque wrench.  Torque Sticks are not accurate unless the
impact wrench used with them has been calibrated with the Torque Stick.
If an installer insists on using Torque Sticks because "they are
accurate", ask him to let you see the records of impact wrench
calibration.  I personally do not allow the use of torque sticks because
the wheel is generally tightened one lug at a time, a procedure that
will induce excessive stress when the second lug is tightened.  Wheels
lugs should be tightened in a crisscross pattern in a stepwise manner.

6.      It is not only tire stores that don't install wheel correctly.
On a recent trip to our local Volvo dealer I watched a mechanic use an
impact wrench to mount wheels.  After a short discussion, the service
manager used a Snap-On dial type torque wrench to remove a lug nut that
was supposed to be torqued to 63 ft. lbs.  It required more than 150 ft.
lbs. to break it loose...  The service manager then, without comment,
loosened and retorqued all 20 lug nuts.

and finally:

7.      Everyone should have a 6 point impact socket and a torque wrench
to use on their lug nuts.  These are not expensive ($7 at Sears a 1/2"
drive 19 mm black impact socket and $19.99 for a 1/2" drive beam type
torque wrench).  These sockets are designed for maximum grip on the lug
nuts and will eliminate most problems with the socket slipping off and
rounding off the nut or bolt head.  Never use a 12 point socket on lug
nuts or lug bolts.  The impact sockets are usually black and are cheap
compared to cutting off even one rounded off lug nut or broken bolt.
The beam type torque wrench is probably more accurate than an dial or
micrometer type torque wrench that has never or not recently been
calibrated.  It is certainly good enough for alloy wheels.

8.      If you lubricate your lug nuts/bolts with oil or antisieze, you
have to change the torque specifications to adjust for the lubrication.
Generally, torque should be reduced by 20 to 30 percent, depending on
the lubricant you use to insure proper bolt tension.  You must find out
what your oil/antisieze specifications are before you do this.  However,
don't take my word for it.  Find out for yourself.

I think that about covers it from me.

Ed McLean