Isn't the latter the correct size?

 

most people get the thinner tire cause that is what is recommended by Tire Rack etc.

 

i got 225/40 cuz that was what was recommended

 

Wheel width. Why not stick with a 45-series tire for more meat?

 

225/40/18 is also less expensive then the 235/40/18

 

Yeah, I guess the real question is why not 225/45/18?

 

Ugh... you already started this topic on acura-tl.com and got really good, correct responses.

So to answer your question again, why don't you refer to the topic you already started and got 2 pages of replies to:

http://www.acura-tl.com/forums/showthread.php?t=82442

 

Let me make this clear as day:

Stock size tires 215/50/17

Tire diameter (inches) = 25.46
Tire section width (inches) = 8.46
Tire sidewall (inches) = 4.23

225/45/18
Tire diameter (inches) = 25.97
Tire section width (inches) = 8.86
Tire sidewall (inches) = 3.99

225/40/18

Tire diameter (inches) = 25.09
Tire section width (inches) = 8.86
Tire sidewall (inches) = 3.54

235/40/18

Tire diameter (inches) = 25.40
Tire section width (inches) = 9.25
Tire sidewall (inches) = 3.70


225/45/18 Has a larger sidewall which will most likely rub if the car is lowered. That extra 1/4" means alot. It is also over a 1/2" larger in overall diamter, again more likely to rub.

225/40/18 Has a much smaller diameter, this will make the car not appear to be as low, a much smaller sidewall too; easy on the potholes.

235/40/18 Has the closest to stock size overal diameter, the widest section width, and a higher sidewall than the 225/40.

These are all GOOD things. Overall diameter being so close to stock won't affect your speedometer or your odometer as much; widest section width means the amount of rubber you have on the road is greater; higher sidewall will protect your wheels and give a better ride.