Please explain wheel offset
Race Director
Joined: Jan 2000
Posts: 10,375
Likes: 3,385
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.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer
Brett Foote
10 Things Every Corvette Owner Needs (2026 Edition)
Michael S. Palmer
8 Most "Only Corvette Owners Understand" Quirks and Problems
Pouria Savadkouei
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years
Joe Kucinski
How Much Horsepower Every Corvette Engine "LOST" in 1972
Joe Kucinski
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!
Michael S. Palmer
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
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: 10,375
Likes: 3,385
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