BMW E66 2006 Perfect Tire size?

[gektor21]

Hello
When driving the car, the clock has the disks 7' E66 750Li BMW LA wheel, star spoke 95,
Tire of the same size 255/40 | 235/45

What do you think about this?
The car drives quite smoothly
Can the sizes be changed?

[pbonsalb]

I think you can put more tire on 9 and 10 inch wide wheels. I remember my E90 M3 had 8.5 inch wide fronts with 245 and 9.5 inch wide rears with 265. Some owners would go 10mm wider front and rear on those wheels. I’ll let you look up a tire size comparison calculator online, but maybe 255/40/19 front and 275/40/19 rear would work. I am not familiar with the E66 wheel well clearance, so I would try to get input on that.