Been trying to understand tyre markings on my trailer tyres.
It is marked as 205 75 R14

That should mean (I think) rim diam is 14", height of tyre is 75mm and
width is 205mm.

Form this you would assume overall diam of Tyre would be 14" (i.e.
355mm) plus 2 x 75mm so overall width of 505mm
Yest if I measure it the overall width is 635mm significantly
different.

Anybody know why the discrepancy?