4 1/2" offset~
Thread Starter
Heel & Toe
Joined: Mar 2003
Posts: 22
Likes: 0
From: Pennsburg PA
4 1/2" offset~
What is the correct way to measure offset? This is how I understand it;
If you were to strike a line across the inside lip of the rim and measure from that line to a similar line struck across your lug pattern, that measurement would be 4 1/2".
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If you were to strike a line across the inside lip of the rim and measure from that line to a similar line struck across your lug pattern, that measurement would be 4 1/2".
:flag
Melting Slicks
Joined: May 2001
Posts: 2,812
Likes: 4
From: Gig Harbor Wa
Re: 4 1/2" offset~ (robs70vette)
What you are measuring is not offset, it is backspacing. And the best way to do it is to lay the rim on its face and lay a straightedge of come kind across the back which is now up. measure from this straightedge to the mounting surface. This is your backspacing which should be 4" on a stock ralley rim. It sounds like that is what you did.
Offset a different way of measuring the same thing. Most newer cars and wheels are measured this way. Neutral offset means that the mounting surface is excactly halfway between the front and rear of the rim. Positive offset means the mounting surface is closer the the face of the rim such as a C5 and most ricers. Negative offset conversly is where the mounting surface is closer to the rear of the rim such as a big 4x4 or a deep dish rim.
Backspacing is usually measured in inches while offset is usually measured in millimeters.
Hope this helps.
Offset a different way of measuring the same thing. Most newer cars and wheels are measured this way. Neutral offset means that the mounting surface is excactly halfway between the front and rear of the rim. Positive offset means the mounting surface is closer the the face of the rim such as a C5 and most ricers. Negative offset conversly is where the mounting surface is closer to the rear of the rim such as a big 4x4 or a deep dish rim.
Backspacing is usually measured in inches while offset is usually measured in millimeters.
Hope this helps.
Melting Slicks
Joined: Jul 2002
Posts: 3,000
Likes: 22
From: Boulder Creek California
Re: 4 1/2" offset~ (70 LS1)
It sounds like he said the same thing as you did :confused:
If by lug pattern you mean the mounting surface, yeah that's right. To be measuring offset, you would have to subtract 4". 4.5" offset is pretty impossible. And isn't measuring to the other side of the lug-surface next to impossible without adding and subtracting various measurements or a very large micrometer?
As far as I know, all stock wheels are 4" max. backspacing, are you sure yours are stock and not just an older style? pics?
-Chris
[Modified by LiveandLetDrive, 11:44 AM 4/25/2004]
If by lug pattern you mean the mounting surface, yeah that's right. To be measuring offset, you would have to subtract 4". 4.5" offset is pretty impossible. And isn't measuring to the other side of the lug-surface next to impossible without adding and subtracting various measurements or a very large micrometer?
As far as I know, all stock wheels are 4" max. backspacing, are you sure yours are stock and not just an older style? pics?
-Chris
[Modified by LiveandLetDrive, 11:44 AM 4/25/2004]
Thread Starter
Heel & Toe
Joined: Mar 2003
Posts: 22
Likes: 0
From: Pennsburg PA
Re: 4 1/2" offset~ (LiveandLetDrive)
Thanks guys... When I measure from the inside edge of the rim to the "mounting surface" I get 4". If I put the ruler through the rim to the surface the lug nuts flush out against, i come up with 7 1/2". So, it looks like the official number is 4".
Thanks again guys!!!
:flag
Thanks again guys!!!
:flag
