So I ordered 225/40R18 tyres instead of 215/40R18 that my car originally came with. I remember researching the topic and it seemed perfectly ok at the moment since the diameter change is just 1.3% out of allowed 8% and I assume (will check) that the speedometer will not underestimation the speed as cars overestimate by a couple % from factory so I should be safe on that front. But then I’ve read horror stories from people who got failed even when they changed to tyres listed in CoC or some conflicting information what do I need and when. I also assume you can’t just install any tyre width on any rim width, right? How do I confirm that my combo is allowed? So can anyone with knowledge and experience, confirm if I need any papers to pass the inspection? I changed to 225/40R18 from 215/40R18 on 7.5 factory rims. submitted by /u/Burnt0utDev
Originally posted by u/Burnt0utDev on r/Switzerland