Correct backspacing/offset for 10" wheel

ok i have a 95 ford ranger splash and the wheels i currently have on it are 8" wide and have a 4.5 backspacing. From my understanding, an 8" wheel actually measures 9" wide from lip to lip so the 4.5 backspacing would mean the face of the wheel is dead center of the hoop, same thing as a zero offset. What i am trying to figure out is what backspacing/offset is needed for a 10" wheel to fit in the same position as the 8" wheel currently on the truck. So if the 8" wheel is sitting dead center at 4.5 backspacing then the 10" wide wheel is sitting dead center at 5.5 backspacing. If i was to put a zero offset 10" wide wheel in place of the 8" wheel then the wheel would protrude an inch from the front as well as the back further than the 8" wheel due to the 2" difference in the 8" and 10". So does that mean that in order to get rid of that 1 inch protrusion from the front and keep the wheel even with the fender the way it is now with the 8" wheel than i would add that inch to the backspacing making it a 6.5 backspace? To sum it all up, my 8" wide wheels fit perfect on the back right now. In order for 10" wide wheels to fit the same way i would need a 6.5" backspacing correct?

you are on the cusp of understanding so let me just clarify for you. If you know the backspacing and the width, you also know the frontspacing. If your wheels are 8 inches wide, which you are right are actually 9 inches wide, the lips add a half inche to each side, and your backspace is 4.5, then your frontspace is 4.5 also. That means the wheels you KNOW will fit HAVE to have a frontspacing of 4.5.

Now its just math, simple math at that. A 10 inch wide wheel is 11 inches wide. Subtract the 4.5 from 11 and yes, you end up with 6.5 backspace. You were correct in your thinking, and now you have confirmation.

i can count to 10....

so does that mean the offset is +25mm because the backspacing is 6.5 which is 1 inch from the zero which is 5.5 on a 10" wide wheel. 1 inch is 25.4 mm

yep yep yep

offset is measured from the centerline, it is an inch offset, so yes, +25

Originally posted by bdroppeddak



i can count to 10....

maybe if we spot you 6 and 9

what wheels are you planning on getting Matt?