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Wheel offset. Who has 18/9's??

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Old 12-08-2004, 03:36 PM
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cosmos
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Question Wheel offset. Who has 18/9's??

What offset are people running with 18/9's??

And just so I know, the stock offset for the rear is ok, or what would be ideal?

I want to stick with 18/11.

Thanks,
Old 12-09-2004, 01:43 AM
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mds
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The Cup car BBS racing wheel is 9x18 offset 46, which places its outer edge relative to the fender at the same place as the stock 8.5x18 offset 40 wheel. There may be slightly more tire rubbing at full lock against the brake duct since the additional wheel width is biased toward the inside.
Old 12-09-2004, 03:08 PM
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curtsm
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I have 18x9's on BBS RE794 (Porsche Cup wheels). 50 mm offset with a 5mm spacer = 45mm. There is a bit of rubbing at full-lock.

- curt
Old 12-09-2004, 03:17 PM
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cosmos
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Curtsm,

Where is the rubbing occuring? Inner or outter??

ps. What size and manufacter are your tires.
Old 12-10-2004, 02:38 AM
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curtsm
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I'm not sure which side it rubs, it's only a tiny bit and I haven't really checked it out. I've got Michelin Pilot Sport Cups, 235's.

- curt
Old 06-01-2005, 11:50 AM
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frayed
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Any more information on 18/9 offsets? The stock offset it 40, and the stock wheel/tire combo tends to rub a bit at full lock. Going to a bigger offset, e.g., 45mm as noted above, just makes matters worse.

Wouldn't a 35mm offset work better?

Perhaps the rubbing at full lock is no limited to the brake ducts, and accordingly, no big deal?
Old 06-01-2005, 12:24 PM
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The 18x9 ET 46 is a perfect fit on any 996/986.

If you run rotated camber plates, or Manthey camber plates, then you get another 1/2" of clearance for wheels/tires. So you can run 18x9 ET35, 18x9.5 ET40, even a 18x10 ET42 with rolled front fenders and 3.5 degrees camber.

My 275 RA-1 is 10.94" wide, and we are talking about way narrower wheels than tires.
Old 06-01-2005, 12:37 PM
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frayed
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NJ, so an 18x9 with a range of factory-ish offsets (39-41mm) should work fine, irrespective of rotated/non-rotated camber plates, correct?

Thanks man.
Old 06-01-2005, 12:55 PM
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Originally Posted by frayed
NJ, so an 18x9 with a range of factory-ish offsets (39-41mm) should work fine, irrespective of rotated/non-rotated camber plates, correct?

Thanks man.
Yes.

The wheel will be 7mm toward the outside. The stock wheel was designed to allow clearance on the tall 235/40R18 tire on all the camber ranges provided by the adjustment on the strut top.

You will need to run the strut fully inside (negative camber) if the camber plates are not rotated, and that gives you -1.5 degrees camber at most without shims.

If you want more negative camber then you can use control arm shims (I don't recommend them, because the move the tire to the front and they rub really bad), expand the three camber adjustment holes (the best path so far), rotate camber plates (reduction on caster, not recommended either), or custom camber plates (the path I took).
Old 06-01-2005, 01:01 PM
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frayed
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Ahh, thank you Master.

I'm at -1.5 right now with maxed camber, but will go with more camber (obviously) for track work. I decided against shims for the reason you stated, but didn't realize that there was an appreciable loss in caster from the rotated strut hats.

"Expansion" of the camber holes via the dremel technique sounds unsavory though. Eeks.
Old 06-01-2005, 01:05 PM
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Forgot to mention. I don't think you will be able to run 265 MPSC with a 9" ET40 wheel without expanding the camber holes or rotating the camber plates. Reducing offset will increase track (good) but reduce the clearance for wider tires (not good).

I prefer to run a 265 on a 18x9 ET46 than a 245 on a 18x9ET40.

If your tire choices are 245 or less for the front, you're ok with a 18x9ET40. With the advantadge of increased track by 14mm and a bit wider contact patch due to the wider wheel.

If you want to run 315/335 tires rear you need to stay on 63mm offset or higher. If you plan on running 305 or smaller tires, then the 11x18 ET59 will be a better choice.



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