Tracks on CCKW

[Hanno Spoelstra]

See Tracks on CCKW, an interesting 1941 training video showing how to wade a GMC CCKW. It is fitted with tracks.

H.

[gordon]

Interesting early truck with GMC sign, short wheelbase prime mover version too

Double front wheels with traction devices and overall tracks never got much further than training videos I think. Excellent off-road, but completely useless about 15mph and taking far too much time and effort to fit and remove.

I've seen one or two GMC photos on beaches or sand with dual fronts, but then you can see the additional front tyres are bald, or even a smaller diameter, so that the running surface is not in contact with the ground once on hard going.

[sapper740]

Interesting video Hanno. I wonder how common it was to install tracks, especially over the rear tires in order to improve traction. As Dan Jahn can attest, the fellow in B.C. with the Diamond T's had tracks installed on one of his, a Tipper I believe. I don't know if they were military, after-market, or something he cobbled together. Further, I'll upload a picture of a Scammell with tracks installed suggesting that at least experimenting with tracks on the various vehicles was common. Derek.

[sapper740]

Originally Posted by gordon

Interesting early truck with GMC sign, short wheelbase prime mover version too

Gordon, here's a pre-war (at least for the American's) picture of a GMC Field Artillery prime mover that is identified in the text as a 2 1/4 ton (mistake?). Not being an expert in this area, I don't know if the GMC badging was rare during the war or not, or if it was a case of changed priorities after Dec. 7, 1941 after which large contracts were let and Chevrolet took over? Derek.

[gordon]

That's the 1940 version of the GMC 6 x 6, which is normally referred to as a 3 ton - no idea where they get 2 1/4 from but the rating for the later truck was 5 ton on road and 2.5 ton off road I believe.

They did use that truck to haul artillery, but it was the very length of it that made hauling such a pain, which is why the artillery prime mover version of the later production CCKW was the short wheelbase like the truck in the film - noticeably shorter than the long wheelbase truck in the image.

The badge thing was just metal utilisation. GMC badges were made of metal and secured with a couple of bolts, so they could be done away with to save metal. CHEVROLET stamped their name in the hood side panels, so no extra metal, nothing to save = the CHEVROLET name stayed on all the trucks after the revision.

I believe that early GMC had slightly different axle setups - not sure what, and also the engine displacement was lower than the 270 cu in i n the standardised truck.

[Richard Farrant]

Originally Posted by sapper740

Further, I'll upload a picture of a Scammell with tracks installed suggesting that at least experimenting with tracks on the various vehicles was common.

Derek,

The use of Chains, Overall (as they were termed) by the British, was general practise and all 6x4 and 6x6 were equipped with them. There were different types, the one on picture attached being the Smooth Soleplate Type.

[Lang]

In my scrounging expeditions to old dumps in New Guinea I found many sets of double axle chains. These were not flat plates as in the above film clip but just looked like ordinary wheel chains but went right around all 4 tyres on the rear bogies.

There were so many of them I am inclined to think they may have been part of the standard equipment for GMC's in SWP area.

[lynx42]

In 1965 at Monegeeta Army Proving Ground, we tried out the full track system on a US6 Studebaker. Great fun. Would go just about anywhere. The steering wasn't that heavy. I thought it would have been, but was pleasently surprised. The outer front wheels were fitted with a smaller size tyre. This was to aid steering on hard ground, as without the tracks, only the origional tyres on the front were making contact with the ground. Before fitting the tracks, we let the tyre pressures right down and after the tracks were fitted, the tyres were pumped up to tighten the tracks. This was not an official trial, just a "let's see what it's like" effort,one Saturday afternoon. Unfortunately we took no photos.

[Hanno Spoelstra]

Originally Posted by lynx42

Unfortunately we took no photos.

Luckily, someone else did!

H.

[Hanno Spoelstra]

Originally Posted by Hanno Spoelstra

See Tracks on CCKW, an interesting 1941 training video showing how to wade a GMC CCKW.

Two truck generations later, this is what a Jimmy could do:
http://www.hmvftv.com/watch/16ffcbf3...derwater-Truck

H.

[lynx42]

Thanks for that link, Hanno. Those tracks in the photo are usually used on the front wheels, the rear was set up as a full track over both wheels. At Monegeeta, any and all combinations were tried with varying success. We spent many hours trying to break the prototype International Mk.5, 6 x 6's, once again with varying success.
Regards Rick.