So my friend gave me 2 continental tires and they are 245/40/R18 and my 2 front wheels are kinda worn so could I put those on instead of buying new ones? Would I feel the difference? They look pretty much the same but I just needed someone else's input! Oh and it's for a 2010 maxima

 

U can run em but get matching ones eventually

 

It is 1" smaller, and your speedo will be nearly 4% off.