205/80/16 were standard on a 90 with 235/75/16 as options on alloys. 7.50/16 were standard on a 110. 235/85/16 were originally on optional alloys and then standard on later Defender 110 models. The 7.50/16's have the same rolling diameter as the 235/85/16's, but are the equivalent of a 205 tyre in width.