In my
experience owning CCKW’s for over 24 years, the wheel problem has been
the worst and most persistent problem with these WW2 GM military vehicles.
There are a
number of wheels that will ‘fit’ on a CCKW including M35 wheels. Even
considering just wheels that are made for 7.50 x 20 tires, there are a
number of different designs that will ‘fit’.
Wheel Basics
Back then, there were no such things as tubeless truck tires like there
are now. Back then, all the wheels had to come apart in one way or another
to allow for the mounting and dismounting of the tires.
 | The easiest ones to dispense with are
the so-called Combat Rims. These are like the rims on the DUKW where
the wheel is comprised of two dish-like pieces that are bolted
together with the tire captivated in between. These wheels have the
advantage of allowing the tire to be changed with wrenches and sockets
in the field by unbolting the two sides of the rime from each other.
They have a disadvantage after 60 years of being difficult to get the
tire away from the wheel because they usually have a large flat area
behind the tire that can get rusty and prevent the rim from sliding
over. If the rim happens to have a run-flat insert installed, after 60
years get out the Sawzall for the tire….. |
| Another type is a standard split rim
design comprised of two pieces, the wheel and the lock ring. If you
have seen an M37 wheel apart, this is that type. With this wheel, the
locking ring actually goes under the bead of the tire which prevents
it from spreading and unlocking. This is probably the safest ‘split
rim’ other than the combat rims. |
| A different type used by Chevrolet back
then has three pieces: the wheel, the removable ring and the small
square split lock ring. With this type, the removable ring is
prevented from coming off by the split locking ring. To remove the
split lock, the removable ring must be pressed towards the other side
of the rim to relieve the pressure on the lock ring. Outward pressure
exerted by the tire just keeps the lock ring in place. |
| Then there is the ‘come apart in the
middle’ rims. You can tell these because the wheel itself will have
a raised area about ½” by 2 ½ “right in the middle of the rim.
Sometimes you can see this area when the wheel is mounted as an inside
dual and most definitely when it is the outside dual. These are very
dangerous and most tire places will not touch them. |
| Finally there is the CCKW rim. This is
a somewhat unique design that features a wheel and lock ring. The lock
ring however is ‘stretched’ over the wheel to mount it or dismount
it. To help this ‘stretching’, a couple reduced locking areas are
made into the lock ring. They are not that difficult to ‘stretch’
after you have learned the tricks and done a few. No part of the lock
ring goes under the bead which means that the tire is trying to push
the ring off at all times. |
With any
truck wheel and tire, if you do not know what you are doing or do not have
the proper tools and safety equipment, TAKE THEM TO A PROFESSIONAL! Two
(or more) piece truck rims play for keeps! Most of the ‘old wives
tales’ you have heard about these wheels are NOT ‘old wives tales’.
I personally know of a local young man (at the time) who nearly bled to
death after a ring hit him in the jaw removing most of his teeth and
shattering his jaw….!
I have changed all but the come apart in the middle types and have done
about 40 CCKW wheels myself. I
also now have an older Bear truck tire changing machine that will do 16 to
24 inch truck tires. When you have over 150 truck tires…..
The tire
machine will remove a tire in any condition from a standard CCKW wheel. If
it on there with great amounts of rust from years of being mounted and the
tire is decrepit too, the Bear Tire Machine will literally take the tire
apart!
I take very
specific precautions when re-inflating a tire after being mounted. You
cannot bee too cautious with these wheels especially after 60 years. Of
course the mating areas (locking areas) of the wheel and ring should not
be too rusty or pitted. In my experience, I have never had one too rusty
to be considered unsafe by me unless it was rotted out as explained below.
A good idea that I use it to take a prick punch and put a number of punch
marks on the ring next to the pry slot and an equal number of punches on
the flat surface by the lug holes. This way you can ensure that you
reassemble the correct ring with the correct wheel especially if you are
cleaning and changing a bunch of wheels at the same time. Try to save and
use your best wheels with un-deformed or bent rings on the front of the
truck. Remember that the tire is trying to push the ring off at all times
and that on the front the ring faces out towards people….
The biggest
problem in my experience has been the wheels rotting out. Yes, I said
rotting out, not just rusting. The way these wheels and many others of the
day were constructed is that you had the wheel rim and the wheel hub that
has the lug nut holes. The fingers on the hub were bent over and riveted
to the wheel rim. What happens is that moisture get between the fingers
and the rim. Over time, the moisture eats away at both the rim and the
fingers. If you look closely, you may notice wheels where the fingers have
started to bulge upwards. These wheels are on their deathbed and should be
deflated and cut with a torch to render them un-useable. Worse yet,
sometimes the rotting attacks the rim more than the fingers. This is
really dangerous.
I had a
friend with 42 Chevrolet civilian truck (same wheel construction) who was
driving along the interstate at about 45 miles per hour when he
experienced a catastrophic wheel failure due to the rim rotting out under
a finger. All of a sudden there was a loud bang and as he stated; “I
didn’t think I could stop the truck before I lost every nut and bolt in
it…’ The lock ring did not come off and the tire did not lose air
pressure. What happened is that the rim got about ¾ inch wider in one
place! What that did was make a giant flat spot in the tire that was not
really noticeable. The truck sure noticed! He nursed the truck home and
looked at it for hours before figuring out what had happened. My friend
was lucky that the ring did not come off or that he did not lose air
pressure. The tire was on the front!
Many people
also do not use the correct lug nuts on the front. I have done it too,
used the inner dual male-female nut sometimes with the outside dual nut on
it. We have all seen the single wheel special nuts that are made for the
front, but how many of use them all the time on the front? Recently, I had
a wobble on the front of my Bomb Truck. I assumed that the older
wheel-tire combination might have been a little bent. It was bent, but
bent because three of the six male-female nuts had pulled or broken
through the wheel! I had never seen this happen before in over 20 years
with these trucks!
Copyright © 2005
Stephen Keith
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