Now driving a BMW :(
AO Platinum Member
Join Date: Sep 2002
Location: West Yorkshire
By my reckoning,
185/60/14 has a rolling diameter of 577.6mm
195/50/15 has a rolling diameter of 576.0mm
195/55/15 has a rolling diameter of 595.5mm
So, the 50s will be microscopicly smaller, the 55s will be about 3% bigger. So your gearing and speedo will be raised 3%. Not worth worrying about, but it looks like 195/50/55 is a more accurate size, and this is backed up by 145TR's comments too.
Are you on steel wheels at the mo??
I think the nuts are different....