Please explain wheel offset
Race Director
Joined: Jan 2000
Posts: 10,268
Likes: 3,319
From: Central TX
C5 of Year Finalist (appearance mods) 2019
[QUOTE=stvaughn;1607923336]How is the offset actually measured?[
/QUOTE]
Let's say we have a 19x11 wheel. Wheel width is measured from tire bead to tire bead. However, a wheel that's advertised as an 11" width is actually 12" wide, outside edge to outside edge. With me, so far?
Now, 12.0" divided in half = 6.0". Measure the wheel's backspacing. Let's say that number is 6". Offset on that wheel would be 0mm. (backspace is measured in inches, offset in millimeters)
If I haven't lost you yet, I had my 19x11 rear wheels built to my specs so I could fit a 325 tire under the car. Offset on them is +65. We know that zero offset on that width wheel is 6.0" so convert 65mm to inches = 2.56".
6.0" + 2.56" = 8.56. That means my 19x11 wheels w/+65 offset have 8.56" of backspacing. If you don't know what your wheel offset or width is, you can use this process to figure it out.
I know this sounds confusing, at first, but one you know the basic fundamentals, it all becomes clear.
/QUOTE]
Let's say we have a 19x11 wheel. Wheel width is measured from tire bead to tire bead. However, a wheel that's advertised as an 11" width is actually 12" wide, outside edge to outside edge. With me, so far?
Now, 12.0" divided in half = 6.0". Measure the wheel's backspacing. Let's say that number is 6". Offset on that wheel would be 0mm. (backspace is measured in inches, offset in millimeters)
If I haven't lost you yet, I had my 19x11 rear wheels built to my specs so I could fit a 325 tire under the car. Offset on them is +65. We know that zero offset on that width wheel is 6.0" so convert 65mm to inches = 2.56".
6.0" + 2.56" = 8.56. That means my 19x11 wheels w/+65 offset have 8.56" of backspacing. If you don't know what your wheel offset or width is, you can use this process to figure it out.
I know this sounds confusing, at first, but one you know the basic fundamentals, it all becomes clear.
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Thread Starter
Pro
Joined: Oct 2013
Posts: 506
Likes: 23
From: Union City TN
St. Jude Donor '15
[QUOTE=USAZR1;1607923545]
My Z has a spacer installed by the PO on the rear wheel so that effectively reduces the offset by the thickness of the spacer, correct?
How is the offset actually measured?[
/QUOTE]
Let's say we have a 19x11 wheel. Wheel width is measured from tire bead to tire bead. However, a wheel that's advertised as an 11" width is actually 12" wide, outside edge to outside edge. With me, so far?
Now, 12.0" divided in half = 6.0". Measure the wheel's backspacing. Let's say that number is 6". Offset on that wheel would be 0mm. (backspace is measured in inches, offset in millimeters)
If I haven't lost you yet, I had my 19x11 rear wheels built to my specs so I could fit a 325 tire under the car. Offset on them is +65. We know that zero offset on that width wheel is 6.0" so convert 65mm to inches = 2.56".
6.0" + 2.56" = 8.56. That means my 19x11 wheels w/+65 offset have 8.56" of backspacing. If you don't know what your wheel offset or width is, you can use this process to figure it out.
I know this sounds confusing, at first, but one you know the basic fundamentals, it all becomes clear.
/QUOTE]
Let's say we have a 19x11 wheel. Wheel width is measured from tire bead to tire bead. However, a wheel that's advertised as an 11" width is actually 12" wide, outside edge to outside edge. With me, so far?
Now, 12.0" divided in half = 6.0". Measure the wheel's backspacing. Let's say that number is 6". Offset on that wheel would be 0mm. (backspace is measured in inches, offset in millimeters)
If I haven't lost you yet, I had my 19x11 rear wheels built to my specs so I could fit a 325 tire under the car. Offset on them is +65. We know that zero offset on that width wheel is 6.0" so convert 65mm to inches = 2.56".
6.0" + 2.56" = 8.56. That means my 19x11 wheels w/+65 offset have 8.56" of backspacing. If you don't know what your wheel offset or width is, you can use this process to figure it out.
I know this sounds confusing, at first, but one you know the basic fundamentals, it all becomes clear.
Race Director
Joined: Jan 2000
Posts: 10,268
Likes: 3,319
From: Central TX
C5 of Year Finalist (appearance mods) 2019
[QUOTE=stvaughn;1607923994 My Z has a spacer installed by the PO on the rear wheel so that effectively reduces the offset by the thickness of the spacer, correct?
[/QUOTE]
To better understand, imagine that spacer was attached to the wheel hub. That would reduce the positive backspacing, correct? Less backspace = less offset
[/QUOTE]
To better understand, imagine that spacer was attached to the wheel hub. That would reduce the positive backspacing, correct? Less backspace = less offset