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I think the 18s are the same as the stock 17s??
Stock 8" 17s are listed as +48mm offset, but actually measure +50mm with
a 6.47" backspace.

Larry
 

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A few mm positive on the front, could make a difference.
On some cars, the stock offset rubs the strut.
On the rear it wouldn't matter.

Larry
 

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A few mm positive on the front, could make a difference.
On some cars, the stock offset rubs the strut.
On the rear it wouldn't matter.

Larry
Even if it did have more positive offset it would be extremely easy to fix with some ARP wheel studs and a thin wheel spacer. When you widen stock wheels like I did with my rear wheels the extra inch made the offset +61mm (half the total of the addition plus the original 48mm). I brought that back to +56mm with ARPs and 5mm spacers. You can go up to about 7mm and still be sufficiently on the hub. Considerably too small of an offset is much more of a problem.
 

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^^True, but you need hubcentric spacers, if you exceed about
4mm thick, or the wheel bore won't rest on the hub. Plus, this is about the
max to get a full lug nut on the stock studs.
A spacer over about 4mm needs to be hubcentric to the hub and have
a hubcentric fit to the wheel, also.
Also need longer (and stronger) studs, as svede stated.

Larry
 

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I use a 5mm spacer. There's still plenty of hub. I think it's foolish to not replace the studs regardless. The stock ones are extremely soft and snap easily. Some have snapped them launching the car. I consider it a safety upgrade.
 

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Discussion Starter #10
The wheels I am looking at are +45mm offset and are 18 x 8 wide. I at least want 245/40/18s on them. I'd may go wider in back, but would also like to be able to rotate them, so I'm not sure which way I will go.
 
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