[MC968CS]

Hi, I would appreciate some advice on offets for the following rims sizes. I can get them made any offset I want, and have no expereince to judge it. Hence needing some help. So....the story

<b>a: My stock wheel offsets are</b>
f 17"x 7.5" offset 65mm;
r 17" x 9" offset 55mm.

I am looking at 18" race rims, and am limited to the following widths in 18" dia by P.club rules. Since we are changing widths the offset will be a little different than stock

<b>b: The builders suggestion would be</b>
f 18" x 8 33mm offset
r 18" x 9.5" 28mm offset

That still keeps the wheels and tires under the body line in their view, but a more aggressive stance. They can do almost anything I want, and want me to let them know if it is too aggressive or ok. I have no idea.

<b>c: Their standard build for those cars would be this below.</b> But I know this is too wide for my rules so not a build option for me.
18x8.5 offset 47mm
18x10 offset 55mm

<b>The questions</b>
1: What is the exact same offset as stock for the 18" x 8" and 9.5" rims, and is there likely any issue positive or negative just building that?
2: Does anyone have a view on the upside and potential issues of building the rims it as per the 'b: builders suggestion' above?

Appreciate some help from anyone across this sort of wheel detail. Thank you in advance!

P.S just finishing the build of my 968CS club level car...started in Nov and I will post pics and details in about 3 weeks :-)

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[flash]

33 and 28 will stick WAY out - the smaller the number the farther outside it goes

i have a 52mm offset on my 10" rear and a 57mm offset on my 9" front - i made them to sit as close to the outside as possible given he tire i wanted to run (285/30 rear and 255/35 front)

there is a wheel calculator on this site

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[MC968CS]

Thank you flash - the numbers look weird vs all posts i read. Is this the calculator you refer too? Wheel offset, even after reading the article, seem a black art to me.
http://www.tirerack.com/wheels/tech/techpa...currentpage=101

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[flash]

not sure why the calculator got buried

http://www.968forums.com/index.php?showtopic=8983

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[MC968CS]

Flash, I am thinking that the following may work without the tyres hitting anything on the car, hoping you may have a view.

R: 18 x 9.5 and 265/35/18 with a 55 offset so it moves both in to the suspension strut by 5mm and out to the fender by 5mm
F:18 x 8 and 235/40/18 with a 55 offset so it moves further away from the strut by 5mm, and out to the fender by 15mm....beyond that am unsure if it will hit the fender on lock on the track, or if I can push the front track out more for a track car....

Comments?

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[flash]

that works fine

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[MC968CS]

Thanks flash

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[Torbjorn968]

R: 18 x 9.5 and 265/35/18 with a 55 offset so it moves both in to the suspension strut by 5mm and out to the fender by 5mm
F:18 x 8 and 235/40/18 with a 55 offset so it moves further away from the strut by 5mm, and out to the fender by 15mm...

I have used 18 x 10 ET 47 at the rear which is close one side but works with 295/30/18. There is actually quite a difference between left and right on my car...

Forward I tried the same ET with 255/35/18 just on the jack in the parking lot. Although a close shave it looks as if it will work unless something happens with the geomtery under compression of the suspension. Interrested in your opinions here. 17x9" ET 55 works forward, 18 x 10" ET 47 would mean another 5 mm of wheel on the inside. Was thinking of using these with 265/25/18 Michelin Cups.

Any danger in trying with max danger being a tyre wear and funny noises?

Best

TL

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[MC968CS]

Wish I could help more. I can add that we are worried about using more than a 15mm wider offset than stock, taking account of tyres size, on the track, with serious turn or lock, so am taking a conservative approach to avoid rubbing.

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