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Join Date: Apr 1999
Location: Denver, CO
Posts: 114
Wheel Offset

Hi everyone-
At a local used tire and wheel shop I have found a set of 7" and 8" three piece Compomtive wheels that have the 4 on 130 bolt pattern - they are beautiful. Before I purchase them, does any one know the exact offset measurements of the 7 & 8" fuchs? This is an "all sales final" deal as they are used and being that I am in the middle of some suspension work I dont trust myself guessing on measurments. Thanks to all
Scott S.
Old 08-23-1999, 06:56 AM
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Join Date: Jan 1999
Location: Cookeville, TN, USA
Posts: 40
I think I'm correct in saying that, with the exception of wheels to be used with flares(in other words, where the actual track will be increased by means of moving the wheels further outboard, using spacers or "deep-dish" wheels), the offset remains the same, being the dimension measured from the wheel centerline to the wheel mounting surface. By retaining the same offset, the wheel remains centered within the fender/wheelhouse volume. Width increases apply equally to the inside and outside of the wheel.

I just measured one of my Mahle 5-lug wheels and arrived at an offset of 39mm. There is confusion aplenty as to whether this is referred to as positive or negative, depending on what article/specs you read. To simplify and clarify, the Mahle has a bigger dimension from the inner rim to the mounting surface than from the outer rim to the mounting surface.

Sometimes only the backspacing is given, which doesn't tell the whole story, unless the total wheel width is also given.[Offset is the backspacing (the dimension from the inner rim to the mounting surface) minus half of the total wheel width]. In the case of the Mahle, this would mathematically work out as "positive" offset.

One thing you've got to watch is the carcass width of a tire that can be used with the wheels you're contemplating. Tire carcass widths (actual dimension from sidewall to sidewall) are specified for a nominal wheel width, and for every 1/2" increase in wheel width beyond the design nominal, the carcass
width increases by 0.2". Without modifications to the rear fenders of a 914, a 205 tire is about as wide as you can go without the tire rubbing the fender. Actual carcass widths will vary from brand to brand, even though the size is specified the same, so that where a "brand A" 205 doesn't rub, a "brand B" 205 might very well cause a problem with rubbing.

Please excuse my rambling, but this is a tricky issue, especially in cases where you've got to commit to the purchase of wheels/tires without a chance to return them if they're unsatisfactory. I hope my babbling helps!
Old 08-23-1999, 05:31 PM
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Join Date: Apr 1999
Location: Denver, CO
Posts: 114
Thanks Brian,Jim. The wheel shop has allowed me to borrow a front and rear to take to 3R Automotive(a local Porsche race shop and PCA tech station)
-S Schroeder
Old 08-24-1999, 08:01 AM
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