I currently run the stock tire set up on a 2017 C63s [255/35R/19 and 285/30R/20] with Michelin PSS. I am lowered on HRE and running spacers all around [lol I can't remember if they're 10 or 15mm]

I would like to go to 265/285 with Michelin Pilot 4S and am wondering what the correct aspect ratio for the tires would be - 30 or 35?

Thanks

Assuming this is a coupe, if you’re going up to 265’s fronts, you should consider going up a size in the rears to 295’s.

The ideal size I’d run if I went with a 295 rear is 295/30/20R, 265/35/19F.

Right, right, My 285 rear was a typo. I meant to say 295.

Thank you for the tire size. Much appreciated!

No prob. You can even go up to 275f / 305r like I did, but it seems that the more common setup people choose when going up in size is the 265f / 295r setup you're wanting to go with.