I fully know the OP is talking about his pony rims. However, you brought up speedo calibration into this topic, so I wanted to remind, the car was originally calibrated to a 225/60/15 size, 91-93 pony stock size is irrelevant there.
225/60/15 = 25.63"
245/45/16 = 24.68"
Or 15/16" smaller which I stated. Wasn't arguing your math on a stock pony vs his tire, but that the comparison was off for calibration talk.
I had agreed with you the OP has to take the smaller size into consideration. Maybe he puts 50,000miles annually, maybe 500, I don't know. He has to consider it... Me personally, I've put 1,500miles on my car in 3 years, and it's a pig on gas regardless compared to most anything on the road these days. From my perspective I do things visually. Really I was agreeing with you on that whole bit, adding that with mechanical speedo setups they are not 100% accurate to begin with. The OP is already driving on almost the same tire diameter up front as is, which I stated in my post you did not quote. He takes his setup into consideration already, but said nothing about long tubes, and ground clearance issues blah blah blah. I've given my advice based on the info given in the thread.
Anyways seems to be a lot of clutter in this thread now, I will pull out.
GL with the tire search
I think it's going to come down to opinion on if the technical difference is worth it or not.
Gas mileage or minimal extra mileage on a car really doesn't come into play unless the has well under 100,000 miles on it. And if it's not a daily driver it probably only costs you a couple dollars a year extra.
Most cars will have 3.73 gears, which does not have a perfect speedo gear anyway.
I'd say most people learn to work within the perimeter of their speedo's personality, so a couple mph off is normal.
Also, i ran all the tire sizes above, 225 55 16 on a lowered car looked terrible in the front.
245 50 16 looked terrible in the back when the fronts were 225 50 16. So couldn't use the 55 series tire up front, which meant i couldn't use the 24 50 16 out back.
255 bfg drag radials looked terrrible no matter what.
The perfect height really was 225 50 16 in the front and 245 45 16 out back. (or all four at 225 50 16).
225 50 16 is also the saleen mustang factory tire size for all their 16 inch wheels.
Take a look at some of these pics, i ran the black 16 inch ARE 5 stars.
Picture Search Results - MustangAttitude.com
Is it worth it to alter the speedo a little and possibly put a few more miles on the car? IMO, absolutely, i did it, and i would do it again. If the car isn't a daily driver it's only a few miles a year, i don't see the big deal.
Is it worth it to everybody? Probably not, but for those that want the perfect look it is.
Gas mileage or minimal extra mileage on a car really doesn't come into play unless the has well under 100,000 miles on it. And if it's not a daily driver it probably only costs you a couple dollars a year extra.
Most cars will have 3.73 gears, which does not have a perfect speedo gear anyway.
I'd say most people learn to work within the perimeter of their speedo's personality, so a couple mph off is normal.
Also, i ran all the tire sizes above, 225 55 16 on a lowered car looked terrible in the front.
245 50 16 looked terrible in the back when the fronts were 225 50 16. So couldn't use the 55 series tire up front, which meant i couldn't use the 24 50 16 out back.
255 bfg drag radials looked terrrible no matter what.
The perfect height really was 225 50 16 in the front and 245 45 16 out back. (or all four at 225 50 16).
225 50 16 is also the saleen mustang factory tire size for all their 16 inch wheels.
Take a look at some of these pics, i ran the black 16 inch ARE 5 stars.
Picture Search Results - MustangAttitude.com
Is it worth it to alter the speedo a little and possibly put a few more miles on the car? IMO, absolutely, i did it, and i would do it again. If the car isn't a daily driver it's only a few miles a year, i don't see the big deal.
Is it worth it to everybody? Probably not, but for those that want the perfect look it is.