Originally Posted by FPenvy

easiest and quickest way is just use tireack as your bible. they have every spec for these tires including overall diameter.



245/40/19 is 26.9" OD and the 305 rears are 26.3" OD so you're fine in that area.



now I will say 2 things on these setup you're going with.



1. a 60mm difference between front and rear widths may throw you some extra under steer. I'm at a 40mm difference and from what I've gathered and have been told it's about the top of the limit before introducing a little extra understeer. some may not notice it based on not driving their car very hard others who do will. not knowing what your plans are with the car that is up to you. this is why I went with a 265/305 set up. stock specs on sport package is a 30mm difference and nismo it's a 40mm difference.



2. It may be my OCD but I could/would never run different front and rear tires especially if one is a much higher performance rated tire vs the other. just could lead to issues if driving hard and whatnot. in a moment of desperation when my rears almost were on the verge of blowout due to inside wear I threw 2 new rears on to get me through 2 weeks until I put the car away for the winter.



i'd suggest going with 4 new matching tires and possibly bumpin up your front width. but I don't know you situation nor driving aspirations so it's ultimately up to you in the end.



in closing your current path of 245/40/19 RE050A's and 305/30/19 rears should do fine regardless of my above suggestions.