CMP tyre manufacturers

[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