I just bought some used rims & winter tires for my 2012 Maxima, but did not realize the rubber was 245/40/18 & my factory tires are 245/45/18.

I am running any risk to my car other than my odometer showing I am going 3.6% faster than actual?

Hi Harry.

Welcome to NICO!

There should be no problem with running the different size tires as far as mechanical safety. You are correct that your odometer will be off and it sounds like you've already found a calculator to tell you how much. It might have a small detrimental affect on gas milage... but so does winter blend gas and cold weather anyway. The trade-off for the safety is worth it. Oh.. and they might look a little worse visually.. but again.. no big deal.

Enjoy the new winter tires and stay safe!