The GMC CCKW

When tire chains were installed on a g506 or g508, did they put them on all the rear wheels or just the outer ones? How about the front axles?

It looks like it would be a pain to install chains on the inside rear wheels.

John

Hi John,

Here is a page from on old Army PS magazine that shows the tire chain combinations on military all wheel trucks.

Chains come in two configurations. Single set and a dual set that covers both wheels on a dual set up. They can be used in various combinations depending on what you have.

They are heavy and take up a lot of storage room. While authorized, I don't think most vehicles carried them unless the situation required it. I store mine in 5 Gal pails and it takes five pails to store a set for a CCKW. The chain set size are usually marked on the retainer clip and should say 7.50X20.







They are not too bad to install once you get the hang of it. Unless you and the truck are already up to your axles in mud. Then it is ugly.

Cat Man

I asked this same question some time ago. The information given by Cat Man is interesting, and I'd like to enquire from what year was the Army PS Magazine he quotes from, published ? My own investigation unearthed different results for the 6 X 6 set up, advising that if a full set of chains was not going to be fitted, the outer wheels on both rear axles, together with
the front axle should be dressed. That is if only four chains are to be used on the rear, the four outer wheels be fitted, i.e. both axles

This came from a WWii Military Manual,........................... which I will now have to find, to quote the reference.

I'll start looking.

.........................and for the detail seekers, this may be just what you're looking for:

http://www.milweb.net/classifieds/large ... 9304&cat=8

quite a bargain I'd say !!!!!!!

The reference I have is:

FM 25-10. Basic Field Manual of Motor Transport ( March 12, 1942.)
Section II. Preliminary Instruction
Para 16.a.5 Chains & Traction Devices:

a. Chains.-Chains are generally necessary in mud, sand,
snow, or slush-ice. Chains should not be used on ice-covered
roads when they cannot bite into the ice. The following general
rules apply to the application and use of chains:
(1) Chains are applied before the vehicle becomes mired.
(2) Chains are so applied that rotation of the wheel tends
to close the chain fastenings. If improperly installed, rotation
of the wheel opens the fastening and the chain will be
lost.
(3) Fairly loose adjustment gives better traction and less
tire wear than tight adjustment.
(4) On all-wheel-drive vehicles without center differential
or other compensating torque device, chains must be installed
on all wheels to prevent unnecessary strain.
(5) When only single chains are provided for dual-tired
wheels, they should be installed on the outside tires.

Now I know this is open to interpretation, but some where I have corroboration of this, explaining that this allows the lead wheel to clear the path and the trail wheel to give grip. For this to happen of course, the chains have to be in-line.


Any thoughts ?

Well John,

As you can see, you have now opened up the "Tire Chain Can Of Worms"!

Let me first say that I live in a region where it snows - a lot! And we plow and dig and drive on chains a fair amount. I recently completed some research on military tire chain placement for an upcoming magazine article including comparing WWII, Korean and later vintage manuals. There is a good deal of conflicting and corrisponding information that will confuse us all. So I went with the most current line of thinking which is Issue 420 US ARMY PS Magazine Nov 1987. Remember that 6X6 trucks were a new inovation in the 1940's and we have driven a few thousand miles on chains in snow and ice since those 1940's manuals were written.

If you study WWII winter war photo's you will see different combinations of tire chains on all wheel drive trucks. Everything from all chains on all wheels to a single chain on one wheel of a 6 wheel vehicle. Sometimes under combat theater conditions, that was all the chain that was available. Even one is better than none.

I think it was Col Theodore Roosevelt that said "Do the best you can with what you have, were you are." That applies to tire chains on military vehicles too.

If you gotta go, chain up and drive on!

Cat Man

I tried the chevy out today in some light snow. It didn't mind crawling along in 4-5" of light snow, but when I hit a drift(maybe10-12" deep) I could feel the wheels hop a bit. I guess if I was serious about driving it in winter, chains would be a must!

I could feel the wheels hop a bit

Careful! Chevys were known to break axles. I have replaced one already and low range makes it worse. 2x as much torque

It's OK. As soon as I get any wheel hop I back off quickly. It's the same when I drive my old jeep. I like these old machines too much to abuse them!

John

Cat Man wrote:Hi John,
Chains come in two configurations. Single set and a dual set that covers both wheels on a dual set up. They can be used in various combinations depending on what you have.

They are heavy and take up a lot of storage room. While authorized, I don't think most vehicles carried them unless the situation required it. I store mine in 5 Gal pails and it takes five pails to store a set for a CCKW. The chain set size are usually marked on the retainer clip and should say 7.50X20.



They are not too bad to install once you get the hang of it. Unless you and the truck are already up to your axles in mud. Then it is ugly.

Cat Man

Nice set of chains, how do the ends of the 3 long chains fix together, are there any tensioning on them and are they WWII age ?

R Cubed

dr deuce wrote:

I could feel the wheels hop a bit

Careful! Chevys were known to break axles. I have replaced one already and low range makes it worse. 2x as much torque

Does this apply to banjo axled GMC trucks as well, aren't the axles of these to types of vehicle the same ?

What about GMC split axles do these suffer from breakages, which are the tougher axles ?

On the CCKW, you are spreading the torque out over 3 axles. If one looses traction. you still have 2 others. With the Chev....

I do not know about the splits or banjo CCKWs breaking axles. I have not personally heard of any though I am sure they happened. And on a split, think about trying to get all those little parts out...

Remember the metallurgy back then was not as good and the Banjo axles had 10 splines. Newer trucks tend to have more finer splines. Less stress on just a few.

Karoshi wrote:.........................and for the detail seekers, this may be just what you're looking for:

http://www.milweb.net/classifieds/large ... 9304&cat=8

quite a bargain I'd say !!!!!!!

What does this link to ? as it does not seem to work for me, do you have another link or describe what its about ?