In theory I heard it should be but look at the doughnut tires they provide now a days, I dont believe they are the same size as the main tires. Remember spares only made to get you to a point where you could get your main tire repaired nothing more. Over the years I have changed tire sizes on my cars and retained the same size spare that were in the cars originally, even had to use them on occasion and in some cases they werent even close to being the same size as the main tires on my car and never encountered problem, then again I never drove at high speeds and got my tires repaired ASAP.