The new engine have also a new front suspension legs, driveshafts etc etc. Also I know that 2.0 calibra was with 195/60/15 or with 205/55/15 tyres, and have the 150mph(?) speedometer with 8k max rpm rev clocker.
My car is with 140mph-220km/h speedo and 7k max rpm rev clocker and have tyres 195/60/14 and it will becomes 205/45/16 with my new alloys. Both sizes have the same diameter.
195/60/14 & 205/45/16 = 590 mm (with 140mph-220km/h speedometer works correct)
205/55/15 = 60.65 mm (with gsi 240 kmh+ speedometer)
195/60/15 = 61.5 mm (with 240 kmh+ speedometer)
Which speedo must i use without have wrong readind from speedo if I use my new tyres with the same diameter with the olds (590mm) but with the new suspension legs etc etc?.
The 140 mph max or the bigger from a gsi?
think your worrying about nothing, all Speedos are about 5% inaccurate anyway. Just try to keep to the same outer diameter of the wheel as bossible, ie the bigger the alloy, the lower the aspect ratio on the tyre wall.