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      02-02-2013, 03:12 AM   #1
///BYU
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Drives: AW 1M
Join Date: Aug 2011
Location: Salt Lake City, UT

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Need Help Before I Place My APEX ARC-8 Order

Hello All,

I could use your help before I place my order for the APEX ARC-8 group buy. Here's what I'm looking at:

18x9.5” ET35 square setup
18x9.5” ET22 square setup

My situation is as follows:
  • Stock 1M, daily driver
  • Plans for 1-3 track days a year
  • Plans to mount Michelin PSS 255/40R18 at all four corners. If that proves to be too narrow I'll move up to 265/40R18. I'm more interested in having the "right" amount of traction vs. having the most traction possible (I know for some of you it's the same thing, but hopefully you'll understand what I'm talking about).
With either setup, rubbing should not be an issue. This is a question about suspension and chassis geometry.

I'm keen to maintain the stock 1M geometry as much as possible. In particular, the wheel/tire centerline so there is no change to the width of the track, scrub radius (does anyone remember that thread awhile back? ), etc. I know the tire diameters will change slightly because of the 18" size and the square setup, but other than that, I'd like to make it so nothing else changes.

The 18x9.5” ET35 wheels with a 5mm spacer in the front and a 12mm spacer in the rear make it so there is almost no change to the wheel/tire centerline. The front wheels move to the outside 1mm each and the rear wheels move to the outside 2mm each. The only problem (if it is a problem) - spacers are needed.

The 18x9.5" ET22 wheels move the wheel/tire centerline 9mm to the outside in the front and 3mm to the outside in the rear. When you add the front wheels together, the track becomes 18mm wider (0.71 inches) than stock. I know people will say wider is better, but I'd rather not mess with a good thing.

So which is better for my situation - maintaining the stock geometry (almost), but having to use spacers, or moving the wheels to the outside a little and not using spacers? In particular, would there be any issues with running spacers at a track day?

Thanks for the help!

Last edited by ///BYU; 02-02-2013 at 05:00 PM..
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