And hopefully it was the 235/40 and not the 45 series.

 

Yea, I ended up going with 235/45 in the front. No rubbing whatsoever. For people in the future looking up the same fitment, 235/45 on a 17x9 +42 up front will fit without having to pull your fender, however, it does poke a bit, and i'm not too fond of that. Meh, I'll live with it.. 255/40 in the rear btw.

 

Its more about the tire being taller than the rear 255.

 

I thought that was more of a percentage of the width.. or something like that. So I believed it would be somewhat close enough if rear is like 40 percent of 255 and front is 45 percent of 235 or yea, idk, I don't understand that at all lol.

 

Sigh. I cannot count how many times I have had to explain what should be very simple especially to car guys on a car forum. Yes the second number is a percentage of the first number in a tire size. So a 255/40/17 has a height of 102. A 225/45/17 has a height of 101.25. A 235/45/17 has a height of 105.75. It may seem minor but you are measuring by mm it does make a difference. It's really not that complicated.

 

And you don't even HAVE to understand the math, you can just look up the measurements the tire manufacture hands you when you go to pick your size. At this point I know all the 17" overall diameter specs by heart, like many of us do I think. If you care about maintaining the best steering feel and quick turn in/handling of the S, when faced with a choice for 235's, almost always better to go with the shorter 24.3" 235/40. You can pair it with either the 245/24.7" or the 255/25.1". It visually looks better anyway.

 

What we really need is a 235/42.5/17. Someone get a tire manufacturer on board, I'm sure they would sell hundreds.

While we are at it, a 275/35/17 or 285/35/17 would be nice also.

 

Okkk, so apparently the sweet spot to match with 255/40 would be either 225/45 or 235/40. I understand now, my front tire's diameter is .3" taller than the rear, so my car is .15" higher in the front than the rear. How detrimental would that be? I'm tempted to take a loss and sell these for what I can and buy a new set of tires now.

 

will I regret going with 18x8.5 +47 with 255? front fenders will be 15mm wider and 1.5 in drop. I drive hard!

 

IMO it's more of an aesthetic concern and a fairly minor one at that. There is no doubt a 235/40 would offer better fender clearance, although the 235/45 should be ok as well. Steering response might be marginally better with the lower profile tire. It just depends how much you think it will bother you, most people won't notice. Also, I ran a 235/40, 255/40 combo and I did not really care for that side profile look either. I would rather have the front smaller than the rear, but the difference (24.3", 25") is larger and more noticeable. I went back to a 225/45 front tire, even with a 9" front wheel. 245/40 is the other option but might require a slight pull depending on camber and ride height.