Wheel swap?

Afternoon.
I've just got back into the scene with a S3 Dormobile having spent years on newer Discoveries. I'm planning on swapping the 750/16 and steel wheels with a set of 235/85r16 on a set of steel modulars. I seem to recall that the wheel studs needed changing when this was done, but I'm not 100% sure. Any ideas or can I get away with a straight swap?
VMT

I think it depends on the thickness of the rim - the previous 8 spoke steels I had on were marginal on stud length. The ones that I have now must be thinner as you can get the nut on a load further...