How's the track width measured in dual wheel rear axles?

[Rolo]

I'm still trying to find out what newer, better and slightly wider rear axle I can update my Mark 1 with ,(body width 2050 mm) and this is what I found:

2,402 cc 2.4 liters in-line 4 engine with 89.9 mm bore, 94.6 mm stroke, 19 compression ratio, overhead cam and four valves per cylinder
Rear-wheel drive

4.63:1 axle ratio

beam rear suspension rigid with leaf springs

Dimensions View Full Dimensions Specifications

External dimensions: overall length (mm): 5,376, overall length (inches): 211.7, overall width (mm): 1,974, overall width (inches): 77.7, overall height (mm): 2,018, overall height (inches): 79.4, wheelbase (mm): 3,954, wheelbase (inches): 155.7,

front track (mm): 1,700, front track (inches): 66.9,

rear track (mm): 1,645, rear track (inches):

How can the rear track width in a dual wheel axle be narrower than the front track?

Or should I factor in the width of the two extra wheels in those figures?

Be kind to me; I'm not very bright when it comes to certain things.

[Rolo]

Let's see if I have this one right:

Is the total "length" (tyre wall to tyre wall - which in my book it should be the same as exterior vehicle width), the equivalent of the "track width" PLUS the width of ONE tyre?

And in a dual rear axle is it the "track width" PLUS the width of TWO tyres?

If so that would make the front axle TOTAL length 1830 mm and the rear dual axle 1885 mm, which would put this Transit rear axle almost exactly at the same length as the one in my Mark 1, and an extra 120 mm would be nice to catch up with the 2050 mm width of my camper.

The extra 100 mm of the Bedford dual rear axle is starting to look attractive but it still has 14" wheels and I would like 15" or 16" wheels.

[MrMPuk]

Twin wheel axles are narrower because of the dish on the wheels.

[Rolo]

Twin wheel axles are narrower because of the dish on the wheels.

But how are they measured?

To the base of the studs?

[Luke]

Twin wheel axles are narrower because of the dish on the wheels.

But how are they measured?

To the base of the studs?

thats how ive allways measured them the wheel mounting face!!!

[Rolo]

I thought it could be something like that but I wanted to make sure, thanks.