Father-Son 1974 Duster Project
Yeah OE cop wheels are 15x7 with a 4.25" backspace. The problem is that a 245/60/14 is squeezed WAY down on a stock rallye wheel, it shouldn't even be mounted on a stock rim. Narrowest that tire should be on is a 7" rim, which a stock rallye is not. So, the calculator won't show the actual width of the tire as it's mounted on the car, it's just giving the spec assuming it's mounted on the right size wheel. So when the calculator says it's .3" wider it's assuming it's on a 7" rim, because that's the measured rim width for a 245/60/14 is 7". So what that means is the section and tread width numbers are measured when that tire is mounted on a 7" wide rim. On a 14x5.5 it will be narrower than that, and taller, because of the way it's being squeezed onto the rim.
I ran 225/60/15's on cop rims on my Duster with the 73+ disks. I had very little extra room to the fenders and had to max out my lower front fender to bumper brace to clear the front corner of the wheel opening when turning. The 235/60/15 will be pushing your luck because of the increase in height and width. Increasing just the height, or just the width is easier to figure, the combination of both compounds the clearance issue. I couldn't have run them on my Duster, but my ride height was lower than stock too. It's been done, but things like ride height, body tolerances, tire manufacturer, alignment specs etc all play a role in that.
Yeah OE cop wheels are 15x7 with a 4.25" backspace. The problem is that a 245/60/14 is squeezed WAY down on a stock rallye wheel, it shouldn't even be mounted on a stock rim. Narrowest that tire should be on is a 7" rim, which a stock rallye is not. So, the calculator won't show the actual width of the tire as it's mounted on the car, it's just giving the spec assuming it's mounted on the right size wheel. So when the calculator says it's .3" wider it's assuming it's on a 7" rim, because that's the measured rim width for a 245/60/14 is 7". So what that means is the section and tread width numbers are measured when that tire is mounted on a 7" wide rim. On a 14x5.5 it will be narrower than that, and taller, because of the way it's being squeezed onto the rim.
I ran 225/60/15's on cop rims on my Duster with the 73+ disks. I had very little extra room to the fenders and had to max out my lower front fender to bumper brace to clear the front corner of the wheel opening when turning. The 235/60/15 will be pushing your luck because of the increase in height and width. Increasing just the height, or just the width is easier to figure, the combination of both compounds the clearance issue. I couldn't have run them on my Duster, but my ride height was lower than stock too. It's been done, but things like ride height, body tolerances, tire manufacturer, alignment specs etc all play a role in that.