CMP tyre manufacturers

[Mike K]

Originally Posted by Hanno Spoelstra

And this I have never seen before:

I've not seen that marking myself. Interesting it is 1 and 1/2 degrees. When looking at the British divided rims, the two halves have a pretty flat or level appearance, but apparently there is a 1 and 1/2 degree slope there.

The American system has tires that have the steeper bead angle , I believe this follows on from the normal commercial tire designs of that period.

Some people have reported as having no trouble with fitting the newer recently made ( Chinese ) tyres onto the British or CMP rims so it may be the case that some of the individual brands are allowing for the different tolerances. I spotted a CMP at Corowa with the Chinese tyres on it and spoke to the guy at length about tyres , he made no mention of having trouble with the fitting. He drove the truck across the Nullabor all the way from Geraldton.

Apparently the CMP C8A six stud rims will accept anything - US or British.

[David Herbert]

I wonder what "Shock Pads" are ?

David

[Grant Bowker]

This is a guess, maybe a bad one....
Possibly a reinforcing layer under the tread, either extra rubber or belts of cord (keeping in mind that most of the (high profile) tires of that era didn't need belts as part of their structure to remain in shape).

[Hanno Spoelstra]

This 1939 GoodYear Heavy Tractor tyre showed up recently in a lot of used tyres offered for sale by Bill Ruston

It has that peculiar pattern which I think makes the vehicle slip sideways in certain conditions. AFAIK this pattern was not continued in production later on during the war.

466781943_2996255697192250_9059150315794784231_n.jpg 466597481_2996251323859354_6313083572184857302_n.jpg

466774273_2996255717192248_2214991733756468074_n.jpg 466674931_2996251047192715_7656290609941283577_n.jpg

[Alex van de Wetering]

Originally Posted by Hanno Spoelstra

It has that peculiar pattern which I think makes the vehicle slip sideways in certain conditions. AFAIK this pattern was not continued in production later on during the war.

I remember seeing these in pictures of Morris CDSW tractors..... And I think also on fatcory pictures of 6x4 Leyland or Guy lorries..... But as you say very early war or even pre-war.
I think i have also seen them appear on a 25pdr used as a monument somewhere... But I can't remember where!

[David Dunlop]

That is a very peculiar pattern tyre, Hanno.

If it was possible to mount them on an axle in mirror image of each other, would that cancel out the tendency for the vehicle to side slip in the mud?

With the pitch of all four tyres pointed in the same direction, things could get very interesting on a muddy slope.


David

[Alex van de Wetering]

Originally Posted by Alex van de Wetering

I remember seeing these in pictures of Morris CDSW tractors..... And I think also on fatcory pictures of 6x4 Leyland or Guy lorries..... But as you say very early war or even pre-war.
I think i have also seen them appear on a 25pdr used as a monument somewhere... But I can't remember where!

Found them, Although I now see that the ones on the 6x4 3 Ton chassis are slightly different

@ David. Yes, you would think in mud you would be costantly turning the steering wheel in the opposite direction to counter the movement of the "drifting" vehicle (?).

[David Herbert]

The 3 ton 6x4 in the third photo is fitted with the first pattern of Dunlop Trak Grip tyres. These and the Goodyear and possibly other makes of "diagonal bar" style were very common at the start of WW2 and I suspect that they were a War Dept. design like the various 6x4 standard chassis. I have read somewhere (but have no idea where) that the Dunlop version changed to the later versions with the bars joined at the tyre centre line to reduce side slip in snow and ice and to promote longer tyre life. The more usual Dunlop Trak Grip went through quite a lot of detail changes over the years, particularly to where the tread bars merge into the sidewall. They saved rubber by having a depression in each one, then filled it in again and made the shoulders rounded. This would be a study in its own right.

Early Goodyear pneumatic tyres had a fine diamond tread pattern which became almost their trade mark. When they moved on to newer designs of road tyre they retained the single line of diamonds on the sidewall for many years so it is interesting that the "diagonal bar" Goodyears do not have those diamonds on the sidewall. Is it possible that the one in post #54 is a retread on a Goodyear casing though probably not as the Goodyear Sure Grip in post #44 also does not have diamonds on the sidewall though modern tractor tyres do. We need more examples of this style....

David

[Keith Brooker]

From a tyre manual i have, shows some tyres in use

Last photo of Germans with a tyre from a Guy truck. Photo from my collection

tyre 1.jpg tyre.jpg

tyre guy truck ww2.jpg