G8MNY  > TECH     02.03.21 11:00z 122 Lines 5610 Bytes #155 (0) @ WW
BID : 25472_GB7CIP
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Subj: Wheel Nuts
Path: ED1ZAC<ED1ZAC<GB7CIP
Sent: 210302/0948Z @:GB7CIP.#32.GBR.EURO #:25472 [Caterham Surrey GBR]
From: G8MNY@GB7CIP.#32.GBR.EURO
To  : TECH@WW

By G8MNY                                 (Updated May 20)
(8 Bit ASCII graphics use code page 437 or 850, Terminal Font)

After seeing the remains of 2 wheels that have come off cars & trailers (non of
them mine) in my time, here are some tips to make sure it does not happen to
you.

LOOSE NUTS
If the nuts get loose the wheel will move on the studs making a noise at slow
speed (not heard if U have diesel or it is on a trailer). This movement will
damage the wheel & in bad cases the studs.

       Cracked _.- 
       Wheel  |  |\ \
       Bearing|  |/  \/Huge hole
       Casting|  |~~~~ -Cone for nut worn away
             ==____.====
              Stud thread 
             ==~~~~\====
              |  |___  Mangled stud thread
              |  |\  /
              |  |/ /
              |-_| Wheel

If left unspotted, eventually the wheel nuts fall off & also the wheel. Then
the real damage starts. e.g. bearing casting cracked, wheel break drum or disk
smashed, suspension & or steering gear damaged, let alone you still being on
the road!

CONICAL & SPHERICAL DOME NUTS (Lug Nuts)
Unlike other nuts wheel nuts are conically or dome shaped, this is to stop any
movement of the wheel, as the self centring cones & gripping force take the
load, not the wheel holes on the studs.
         ____                ____                  ____        =====____
       /____             /____\  Double      /      FRAGILE  ڴ____
Wheel       Spanner           Coned           ----KEY----    
 Side  Ĵ Side        Ĵ  Wheel                  !   Ĵ
       \____             \____/  Nut         \____       !   ____
  Cone'                                               NUT      ===== TOOL 

NEVER use the wrong nut type dome or conical types must engage with the
matching impressions in the wheel, the wrong type can fracture a cast wheel!
Keep removed nuts fee of grit, buy not leaving them on the ground.

Key Nuts are smooth cyninder on the outside, or have a rotatable coller. They
have a flowery fairly unique (1 in 500?) key shape cut into the end, that with
a tight fitting matching key tool & it's other tube just about handle enough
torque to undo them. Missing/broken key tool can be replaced if a dealer knows
the No, or takes a photo oe the key nut to order up a match.
 
WHEEL HOLES                              |  | Shaped
These are specially shaped        Wheel  |  |\ \Wheel
steel stamping or castings        Bearing|  |/ /Metal
that have the matching load       casting|  |/-Cone for nut
carrying cone.                          ===========
                                         Stud thread 
The actual threaded stud                ===========
hole is bigger than the                  |  |\-Cone for nut
stud for ease of putting                 |  |\ \
on the heavy wheel.                      |  |/ /
                                         |  | 
GREASE & TIGHTENING
Some makers suggest you do not oil/grease the nuts. But any experienced
mechanic will tell you otherwise. Grease will not loosen a tightened nut! But
it will stop corrosion & seizing of the nut, & it will ensure that the
tightening force applied ends up forcing the wheel centring cone & nut together
(gripping force) & not to a jammed up thread. Copper Slip is one of the best
greases for this. Grease both the thread & the conical surface with a tiny dab.

Never have a load on the wheel when tightening, e.g. use a jack, as the loaded
wheel may give the false impression it is tight.

Garages use air gun hammer spanners, they always seem to over tighten nuts, so
if you ever want to undo an over-tightened nut, you had better grease them!

It is best to tighten wheel nuts in opposition, rather than just go around the
wheel, this ensures the wheel centres properly. (From Greg VK2KGZ) 

Typical tightening forces are 8-12 m-kg (60-90ft-lb). 

JACKING POINTS
Re Garrage mechanics, I stopped one jacking up my van under the body sills, he
was about to crush it with 1/3-1/2 ton of weight, He said it was the stongest
part, so I showed him the reinforced jacking point attached to the heavy
chassis sections designed for the job!

UNDOING NUTS
Make sure you know the thread & rotation direction, as some makes use LH & RH
wheel nuts different on each side!

        Ext Tube
     _..._//            _..._   /       With the jack applied
   /~    //\          /~     ~\/        until only a small load
       //                _ /        is on the tire to stop
    o  /o            o  /o/         rotation use a crank
    _(/)              ( )~          leaver socket (supplied)
   /o/  o            o   o          with an extension tube
    ~                               over it & apply force
   \_     _/          \_     _/         crossing over the wheel
     ~---~              ~---~           centre.
     RIGHT              WRONG

This gives less rotation force to the wheel than apply it on an outer nut,
making it safer on the jack etc. Applying a thump or soft hammer blow may help
but spanner flying off can be dangerous! A wheel brace cross spider can give a
much more controlled way of applying the force but they are large.

If the nut is well seized on, first try a penetrating oil (brake
contamination!) then try heat, either boiling water or gas torch (Hot safety!
Fire Safety!)

Once all the nuts are loose, jack up to more to fee the wheel & give alignment
room when reseating the wheel.


Why don't U send an interesting bul?

73 De John, G8MNY @ GB7CIP


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