1400/20 NDT Tires

[hickjc]

All,

After many years of search, I am considering having a batch of NDT 1400/20 18pr tires manufactured. I am aware that NDCC tires are about but for any wartime vehicle they just don't look quite right, and with the new 10 year tire rule, nearly all this size tire are over this age. For those who are not aware the NDT have a square edge to the tire and NDCC have the more rounded edge. Just trying to gauge an expression of interest at this stage. These tires are not going to be cheap, but obviously the more interest I can get the price will come down.

Jon H

[DaveR100]

The correct wartime size as far as I know for Pioneers etc is 13.50x20. Would it be better to do these? (if it is possible.) The other point is that from the HCVS magazine vehicles built before 1960 are exempt from this rule. I have a set of NDT 1400's but if you switch to 13.50 I could be interested. It will depend on price. PM details please

[David Herbert]

14.00 - 20 was a re-naming of 13.50 - 20 in the same way that 10.50 - 20 became 11.00 - 20. I think this happened quite late in the war. This may have been to reflect the greater outside diameter caused by using the carcass of a road tire but the greater tread depth of cross country tires. Some tires are even marked with both sizes. American vehicles had 14.00 - 20 from the start and British vehicles would never have been built with American style non directional bar grip tread (with the bar at right angles to the centre line of the tread). If one was going to manufacture tires for British vehicles I would have thought that copies of Dunlop Trac Grip or Goodyear (can't think of the name but a V shape tread) would be most representative. There are a lot of Matadors, Militants and Scammells that desperately need them.

Before anyone starts debating exact dimensions, have a look at the original manufacturers figures. It is surprising just how different each make of the same size tire was.

David

[john1950]

Not just the tyre diameter but also the bead width and shape.

[radiomike7]

Not to mention the ply rating, I have seen the Goodyear NDCC 14.00-20 in 12, 18 and 22, the 22 being almost twice the weight of the 12.

[David Herbert]

The problems with bead width and shape only apply to WW2 British design 9.00 - 16 and 10. 50 - 16 tire/two piece wheel combinations. CMP wheels and so tires are the same and all have a different bead angle and diameter to American ones. I believe that the aluminum wheels and Dunlop Trac Grips used on Ferrets were made to the American standard. Fortunately this problem doesn't affect 20" sizes but as Radiomike7 says ply rating makes a huge difference to weight and also ride quality. As we will not be using our vehicles overloaded in combat situations we can go for the least ply rating that gives the carrying capacity needed.

David

[hickjc]

I want them for a staghound, so will be going with the US size and pattern, that if we can find enough people.

Kr Jon

 

[radiomike7]

NDT tyres with the squared shoulder were often known as mud and snow types compared to NDCC which had a rounded profile for cross country use.

Strangely most of the Goodyear 15.00-20 as fitted to Martians and Militants were NDT whereas the 14.00-20 on Scammells and Militants was usually NDCC, check out Rob's Militant tanker on 15.00-20 which clearly has the squared shoulder.

A Staghound weighs around 14 tons so would need the 18 ply as suggested. Last time I looked into buying new 14.00-20s they were circa £700 each and that was about 30 years ago, make sure you are sitting down when you get a quote for new ones now.