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Please help me spec sizes/offsets for my new wheels

Old 01-05-2019, 02:58 AM
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Steve Theodore
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Default Please help me spec sizes/offsets for my new wheels

Hey guys,

I'm going to buy a set of new Forgeline GA1R open lug cap wheels for my 2002 996TT and want to make sure I spec the offsets correctly for my needs as I fear Forgeline may not give me exactly what I want if I just tell them to 'do something aggressive' for my 996TT. My goal is an aggressive street car that fills the wheel wells pretty much flush to fender, so that it fills them out like my OEM GT3 RS. I do plan to retain AWD in case that helps provide more context. I do not want to run wheel spacers, hence wanting to get the offsets correct from the get-go.

Reference Examples
Stock 996 TT: 18x8 ET50, 18x11 ET45 (please correct me if this isn't right, from Google results)
Stock 996 GT2: 18x8.5 ET40, 18x12 ET45 (please correct me if this isn't right, from Google results)
A buddies ultra-aggressive spec on FinSpeed F110s: 18x10 ET38, 18x13 ET46 (this is likely TOO AGGRESSIVE for my needs)

In theory I'm fine with 235 front and 295 or 305 rears as this won't be a track special, so I just want to get the offsets right mainly. I'm only interested in 18 inch wheels, not 19s. If you could share a few pictures of what you've done on your own 996TT, I'd definitely appreciate that too. Thanks in advance.
https://cimg2.ibsrv.net/gimg/rennlis...df2e23ba8e.jpg
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Old 01-05-2019, 03:15 AM
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pfbz
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I'm running 9.0x18 46 offset with 245/40R18 front and 12x18 45 offset with 315/30R18 rear and it's pretty much perfect.
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Old 01-05-2019, 11:27 AM
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32krazy!
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i run the gt2 setup with 305/35-18 drag radials. perfect for me. i have also run the 315/30-18 and never had any issues
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Old 01-05-2019, 12:18 PM
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911mhawk
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BBS e88
Finspeed F14
forgestar f14
Champion rs98
OZ

Get some 9&12 x18 and run 245/40 & 315/30 and you'll have good % for the AWD and more tire choices.
Pwdrhound set me up twice and knows what works well.
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Old 01-05-2019, 12:46 PM
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Road King
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I went with Forgestar F14s sized @ 18x8.5 et45 and rear 18x11 et 38. I didn't want to run spacers either, but I also didn't want to get too aggressive with offsets that could cause fitment issues. Another requirement was the ability to run either Turbo or GT2 sized rubber out back.

Presently, I am running Yokohama Advan AD08Rs in 235/40 and 295/30, reason being the Yok 225/40s are the exact same height and revs per mile as the 295s and I wanted to preserve the slightly taller front to rear ratios.



Will be upgrading to Falken RTK 615+ in 245/40 and 315/30 as soon as the Yoks are toast.
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Old 01-05-2019, 02:32 PM
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Steve Theodore
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Road King, that looks really good. Do you happen to have any shots from straight on from front or back? How close to fender lips do these come as the car is currently configured? Thanks to all who have replied so far.

Originally Posted by Road King View Post
I went with Forgestar F14s sized @ 18x8.5 et45 and rear 18x11 et 38. I didn't want to run spacers either, but I also didn't want to get too aggressive with offsets that could cause fitment issues. Another requirement was the ability to run either Turbo or GT2 sized rubber out back.

Presently, I am running Yokohama Advan AD08Rs in 235/40 and 295/30, reason being the Yok 225/40s are the exact same height and revs per mile as the 295s and I wanted to preserve the slightly taller front to rear ratios.



Will be upgrading to Falken RTK 615+ in 245/40 and 315/30 as soon as the Yoks are toast.
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Old 01-05-2019, 02:55 PM
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hyboost
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Steve

I realize you’re looking for 18” and mine are 19”, but here are some side pics for reference of offsets. I experimented with a few setups before these e88’s were made based on my specs.

Front is 8.5” wide, +43 with 245 tire
Rear is 12” wide, +42 with 305 tire

Had the rear fender lips shaved and am running GT2 liner brackets to clear. No rubbing at all with H&R springs.
Good luck

Rob (ex Supra owner who can’t believe the recent BaT Supra auction)
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Old 01-05-2019, 03:03 PM
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Old 01-05-2019, 03:04 PM
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"02996ttx50
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gt2 offsets 8x12 lowered with H&R reds atop MO30's. fenders rolled.
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Old 01-05-2019, 03:12 PM
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Road King
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This is the best I can find right now



Not totally flush but works for me!
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Old 01-05-2019, 04:06 PM
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Hey Steve,
Yeah, the 18x10x13s won't fit on a TT unless you did some serious work. I have a couple of sets of the F110s you mention on my car but it has a totally different suspension components from a TT. Chris, who is local to you, got a set of these exact F110s from me and is running them on his car but using a mirror image of my old suspension set up with the same components. Here is a pic of it to give you an idea running 275/335s including a shot from then underside. There are many ways to maximize it depending on your particular components. I would go with a 18x9x12 at a minimum which can be made to work with ease on a TT. Always maximize rim width for the particular tire used. If choosing to go with a 235 an 8.5 or 9 and a 9 or 9.5 for a 245. For a 315, a 12. 245/40 and 315/30 are perfect for AWD. 235/40 works too but you are leaving rubber on the table so to speak as a 245 will give you a bit more front end bite. Stretching the tire ever so slightly on the rim will stiffen the sidewall and improve steering response. An 18x9 ET45 and 18x12 ET40 are simple bolt ons. Cheers...


Last edited by powdrhound; 01-05-2019 at 10:38 PM.
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Old 01-05-2019, 09:02 PM
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Steve Theodore
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My thanks to everyone giving me feedback, really appreciated! I have never picked aftermarket wheels for a 996TT before as I inherited a set of 18" Fiske's on my previous 996TT and kept them throughout the 4 years of ownership. This is my first aftermarket set of Porsche wheels ever, so the knowledge is helping me out tremendously. I should have mentioned that my 996TT is lowered on KW V3 coil-overs and the front is indeed quite low, so I do have to at least keep that in mind. It is doubtful that I can raise the car more than 1/4 or maybe 1/2 inch from the people I've talked to, based on knowledge specifically about the KW setup.
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Old 01-05-2019, 11:18 PM
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Looking to make my street only 996 Turbo into a street/track. Moving from 19's to 18's and a brake upgrade for the track. Thanks to the OP and all responses, very helpful!!
K
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Old 01-06-2019, 01:17 AM
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Sent a PM.
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Old 01-06-2019, 02:21 PM
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Steve Theodore
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Again, my thanks to all...you have helped tremendously.

The setup I'm going to go with is:
18x9 ET45 (245/40/18)
18x12 ET40 (315/30/18)

For those who PM'd me about helping to select and purchase wheels, I have a trusted source for Forgelines whom I've bought from before, but I certainly do appreciate your offers.
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