http://www.amazon.com/Shinko-SR241-Series-Tire-Application/dp/B0032W1ZNO
If you want period tires you're going to have to trawl Ebay. There is stuff there
Does anyone know what make was used for Army contracts, Dunlop, John Bull?
I should have realised there would be extensive info on this. But does anyone know if John Bull made army tyres? I once had a '46 Matchless G80 with the original JB tyres. Smooth up to 50 and then was a road drill. And I do know what's that's like as I often worked on construction gangs whilst a student. It was a nice bike that I never should have sold but I did get through trousers at an alarming rate. Turned out someone had left a battery on the seat, for several years.......
The preferred pre-war WD motorcycle tyre was Dunlop, generally the Universal but sometimes with a reference to a 'Competition' tyre at the rear. This was pretty much a 'knobbly'.
With the outbreak of war, it would seem that Dunlop were unable to supply the quantities needed and the factory ledgers show that production used Dunlop and Good-Year 'Extra-Grip' randomly.
The off-road performance of the Good-Year was frequently slated but presumably they were OK on the tarmac which would have made up most of the use of a WD motorcycle in the UK at least.
Firestone also advertised that they supplied the War Office.
During the post-war period, with factories once more free to choose what they produced, other manufacturers undoubtedly tendered for Government contracts.