Good day, I would like to have a somewhat “remarkable” question. I have to add new rims and new tires next summer, because at the moment I drive on 225/45 R17 7×17 ET47. My new planned wheel-tire combination would be 245/35 ZR18 8×18 ET40, on which I would also let my speedometer calibrate, as it otherwise indicates too little (0.9 km/h, to be exact). The speedometer is known to be up to 10 % or 4 km/h too much but no km/h too little. With the help of a “Rei I could find out that the change in the outer edge of the wheel + 20 mm and the change in the inner edge of the wheel + 6 mm would be (see pictures). Consequently, the width of the entire wheel increases by + 26 mm. Now I could theoretically go and measure whether my intended wheel fits into my wheel box. However, since this is too inaccurate for me, my consideration was that I simply because the change in the outer edge of the wheel to my current wheel tyre combination was just I would be happy if someone had already had some experience with this and if this really corresponded with the new wheel in hindsight or if this really fit. Greetings Ravennwest PS: The + 6 mm at the inner edge of the wheel are no problem, because there is still enough space there. PPS: The future wheel is even 3 mm in diameter smaller (roll-off circumference – 0.9%).