Cop car rim size
Sorry, but if most of the wheels you measure don’t have the advertised backspace then it’s most likely that you’re measuring it incorrectly. In this case it’s possible you don’t have the exact wheels I linked, but they still only have one measurement.
Also, just FYI, pretty much all wheels produced in at least the last 30 years have their specifications cast or stamped directly into them. Cast wheels typically have the diameter, width and offset cast into the back side of the wheel where it can’t be seen. Steel wheels are stamped with the same info, frequently on the inside of the hoop so it’s covered by the tire or on the back side of the wheel depending on the style.
Like this. In this case, 17x9, ET 0 (ET is offset). So offset is +0, which is a 5" backspace
Which is exactly what you get measuring from the outer edge of the lip to the mounting surface
He’s not talking about the original 15x7” wheels that all have a 4.25” backspace. He’s talking about a new set of 15x6’s.
Backspace is properly measured from the wheel mounting surface to the outside lip of the rim, not to where the tire seats. Width is measured tire seat to tire seat. Couldn’t tell you why it’s different, but those are the definitions. If it were up to me width would be outside to outside too, because that's easier to measure. It makes sense that backspace is to the outside, you can't measure directly from the wheel mounting surface to the tire seat. And, by measuring to the outside of the lip the backspace spec gives you the exact clearance of the rim to the springs. So, hard parts to hard parts.
Sorry, but if most of the wheels you measure don’t have the advertised backspace then it’s most likely that you’re measuring it incorrectly. In this case it’s possible you don’t have the exact wheels I linked, but they still only have one measurement.
Also, just FYI, pretty much all wheels produced in at least the last 30 years have their specifications cast or stamped directly into them. Cast wheels typically have the diameter, width and offset cast into the back side of the wheel where it can’t be seen. Steel wheels are stamped with the same info, frequently on the inside of the hoop so it’s covered by the tire or on the back side of the wheel depending on the style.
Like this. In this case, 17x9, ET 0 (ET is offset). So offset is +0, which is a 5" backspace
Which is exactly what you get measuring from the outer edge of the lip to the mounting surface
He’s not talking about the original 15x7” wheels that all have a 4.25” backspace. He’s talking about a new set of 15x6’s.
Backspace is properly measured from the wheel mounting surface to the outside lip of the rim, not to where the tire seats. Width is measured tire seat to tire seat. Couldn’t tell you why it’s different, but those are the definitions. If it were up to me width would be outside to outside too, because that's easier to measure. It makes sense that backspace is to the outside, you can't measure directly from the wheel mounting surface to the tire seat. And, by measuring to the outside of the lip the backspace spec gives you the exact clearance of the rim to the springs. So, hard parts to hard parts.
