These are the two correct sizes for R8s as they are the same SLR (static laden radius) so the Speedo cal is correct.Johnny 216GSi wrote:
...the larger alloys were 185/55/R15 and 195/50/R15.
The 185 was fitted from GTi 3 door launch onwards and the 195 fitted to Turbo from Coupe launch. Marketing wanted something bigger for the Turbo but 16s wouldn't fit without lockstops etc. So we just went with the wider section 15".
The 185/55 is an uncommon size now and therefore usually more expensive than the more common 195/50.
