This thread tangent was based upon discussion of a Series Landy.
It is a rough sketch but your point about the Defender rims is relevant.
On a series the Australian 5.5" rims have a 44.45mm positive offset* if you were to fit a 6.5" rim with a 20.6mm positive offset and add the 12.7mm additional width inside it takes the overall to about 33mm, this means that the inside of the tyre is in about the same location as the English rims (569690) which won't impact on our series turning circle. In fact swapping to the 569690 rim or any 110 or 130 rim will allow you to screw in your swivel stops and reduce the series Landy turning circle.
In relation to "Deep Dish" rims the original SIIA F/C rims (543384) which have about 3mm less positive offset to the 1 Ton (569204) and Defender 6.5" rims. The SIIB F/C rims (569203) are even more of a deep dish and significantly less offset. Given that a 1 Ton Series IIII Land Rover is the same chassis diff specification as the SIII Au Army chassis it would be easy to argue that the 569204 is an optional rim on a Military SIII and SIIA an the Defender 6.5" rim is equivalent to that.
* I have done a minor update of the graphic but it still requires a complete re-do. The measurements added are from the Rover 608024 parts catalogue. The measurements indicated "measured estimate" are by using a digital Vernier calliper on the outside of a rim.
And yes I would be happy to extract this tangent into a new thread.
