Wheels that clear GXP & CTS-V brakes [Archive] - GRRRR8.net

KaiserM715

10-01-2009, 07:55 AM

Using one of these brake sets is of great interest to me, but there is very little information as to which wheels will clear the front calipers. Post wheels, stock or aftermarket, that have been shown to clear (I am hoping to see actual wheels that have been fitted rather than hypothetical). For aftermarket wheels, please post wheel make, model and size - including offset.

OEM (Pontiac, Cadillac, Holden):
G8 GXP: all years
Cadillac CTS-V: 2009-? (the ones I would like to have, but seem to be hard to come by)
Holden HSV VE Clubsport R8 19"
Holden HSV VE GTS 20"
Holden HSV VE Pentagon 20"

Aftermarket:
WheelWorx G8 Series (as per G8 V8)
OZ Ultraleggera (http://www.ozracing.com/at-team/wheels/racing/ultraleggera/en) 18x8
Savini Avaraus AV5 20x8 (as per christiancoach)
Breyton Race GT (as per DHmotorsports0)

Any others?

KaiserM715

10-06-2009, 08:52 AM

Bueller? Bueller? Anyone have a GXP with aftermarket wheels who would like to chime in?

Big Daddy G8

10-08-2009, 12:28 PM

I just put on 18x8 OZ ultraleggara's with Dunlop Direzza's as I am taking the car to the track on Monday. The fit over the calipers with plenty of room to spare

BD

G8V8

10-08-2009, 01:47 PM

Mine clear.

KaiserM715

10-09-2009, 05:39 AM

I just put on 18x8 OZ ultraleggara's with Dunlop Direzza's as I am taking the car to the track on Monday. The fit over the calipers with plenty of room to spare

What offset and backspacing did you use?

G8V8

10-09-2009, 07:20 AM

Don't forget, the main problem with the thicker GXP calipers is clearance to the backside of the spokes. For example, 19" GT wheels don't fit because the hit the spokes. There is plenty of rim clearance. They have 56mm offset or something close. My 19" Stern wheels didn't fit because of spoke clearance and they had 40mm offset.

99-LS1-SS

10-09-2009, 07:28 AM

What offset and backspacing did you use?

The offset isn't the only thing to consider. You can have the exact same offset as the GXP/CTS-V and still have clearance issues. Wheel design and spoke thickness matter too.

Here are the Holden HSV offsets and sizes. This should get you in the ballpark.

OEM HSV sizes are:

Fronts - 19 x 8", 5 x 120, +48

Rears - 19 x 9.5", 5 x 120, +57

KaiserM715

10-09-2009, 09:30 AM

The offset isn't the only thing to consider. You can have the exact same offset as the GXP/CTS-V and still have clearance issues. Wheel design and spoke thickness matter too.
I knew this was the issue, that is why I was trying to get input from GXP owners and others who have swapped over to the GXP setup.

Here are the Holden HSV offsets and sizes. This should get you in the ballpark.

OEM HSV sizes are:
Fronts - 19 x 8", 5 x 120, +48
Rears - 19 x 9.5", 5 x 120, +57
Thanks, that is good info.

Ktlplxm

10-09-2009, 02:03 PM

Just look it up on different sites. Most of the GXP owners aren't changing wheels so you'll have to do a little more research on your own

micheal0484

10-09-2009, 02:04 PM

Why can u not put wheel spacers on stock wheels to clear the calipers. They are like $50.00

christiancoach

10-09-2009, 03:04 PM

Savini Avaraus AV5 20" (8"width) will fit GXP brakes. I am not 100% sure of the offset, I bought them used. They clear with about 1mm to spare.

Ktlplxm

10-09-2009, 03:24 PM

Why can u not put wheel spacers on stock wheels to clear the calipers. They are like $50.00

Thread engagement. You have to go well over 1/4 to get them to clear with factory wheels. Then you need at least the diameter of the stud's width worth of engagement to get reliable torque on the stud. With a factory wheel, if you had a billet one made, you could probably pull that off. With most aftermarket wheels, the offset is minimal enough to have the wheel pushed to the aesthetic limit of the car.

KaiserM715

10-12-2009, 10:14 AM

Why can u not put wheel spacers on stock wheels to clear the calipers. They are like $50.00

I would rather not push the outside of the wheel any farther than I have to. Wheels sticking out of the fenders is ok on a 4x4, not a car.

Greg@PacePerformance

10-12-2009, 10:36 AM

The offset isn't the only thing to consider. You can have the exact same offset as the GXP/CTS-V and still have clearance issues. Wheel design and spoke thickness matter too.

Here are the Holden HSV offsets and sizes. This should get you in the ballpark.

OEM HSV sizes are:

Fronts - 19 x 8", 5 x 120, +48

Rears - 19 x 9.5", 5 x 120, +57

Very close specs to the 2009+ CTS-V wheels
Fronts - 19 x 9", 5 x 120, +51
Rears - 19 x 9.5", 5 x 120, +56

DHmotorsports08

10-12-2009, 02:14 PM

Breyton Race GT wheels fit

KaiserM715

10-13-2009, 06:10 AM

Breyton Race GT wheels fit

I didn't see the GXP or CTS-V brake upgrade in your mods list. Have you swapped brakes on your car and are running these wheels or do you know someone who has?

Ktlplxm

10-13-2009, 11:15 AM

If you do a search on tirerack I believe, it says the GT will fit. It has a lot of clearance on the back.

DHmotorsports08

10-13-2009, 05:38 PM

they have plenty of space and have been tested.

I didn't see the GXP or CTS-V brake upgrade in your mods list. Have you swapped brakes on your car and are running these wheels or do you know someone who has?

99-LS1-SS

02-15-2010, 06:58 AM

Very close specs to the 2009+ CTS-V wheels
Fronts - 19 x 8", 5 x 120, +51
Rears - 19 x 9.5", 5 x 120, +56

I thought the Cadillac CTS-V front rims were 9" wide?

Greg@PacePerformance

02-15-2010, 07:04 AM

So it took 4 months for someone so see that typo. Nice to know everyone pays attention to my posts ;)

99-LS1-SS

02-15-2010, 07:07 AM

LOL! I only noticed because I'm back on the CTS-V wheel band wagon. You have a PM. :D

MoonPie

02-15-2010, 08:04 AM

LOL! I only noticed because I'm back on the CTS-V wheel band wagon. You have a PM. :D

I tink I'm jumping on that wagon as well!

DarkPhoenix

02-15-2010, 10:16 AM

MLR

02-15-2010, 01:40 PM

Greg@PacePerformance

02-19-2010, 07:28 AM

Its a good wagon to be on. :)
I have a GXP brake kit on order, can't wait for it to get here. Now if I can just find some pontiac center caps...
BlackBerry9630/4.7.1.57 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/104

I ordered in a CTS-V Center and GXP center cap.
Here are the specs.

CTS-V mounting diameter 2.105"
GXP mounting diameter 2.150"

It seems you might just be able to put the pontiac center in the CTS-V wheel and use some clear silicone in the rear to hold it in.

That is how GM was fixing some Vibe centers under warranty.

G8V8

02-19-2010, 07:39 AM

How much space do you need to clear the GXP/CTS-V brakes. My 19" BBS CH are 9.5 +40mm rear and 8.5 +35mm front. There is almost 2" in the rear from caliper to spoke and 1.5" on the front. Car is 08 G8 GT.

PACE has a template on their GXP brake conversion page. It might help you know if you will fit. The rears are the same on the GXP as the GT rear so any GT wheel will fit if you convert to GXP fronts. I do not think the rear "GXP" conversion has been 100% proven yet but Greg could shed some light. Nor do I know if that rear conversion to Camaro SS rear Brembo brakes will fit GT wheels. I've not followed it lately so things may have changed.

DarkPhoenix

02-19-2010, 02:34 PM

I was considering the CTS-V front and rear brake kits that Pace sells. I asked Greg a bunch of questions and decided to go with the GXP kit. The Camaro SS and CTS-V fronts would be pretty easy, just need to drill the knuckles to accept the 14mm bolts vs the G8's 12mm.
The rears would be a problem. Greg can elaborate, but you would lose the function of your e-brake. It would take a good but of custom work to get the e-brake to work.
I am very happy with the GXP front brake kit, as you can see in the parts review section. Greg was a big help and Pace shipped everything out quickly.
Greg, how much do the GXP center caps run?
BlackBerry9630/4.7.1.57 Profile/MIDP-2.0 Configuration/CLDC-1.1 VendorID/104

StockG8

02-19-2010, 05:17 PM

So that's only 0.045" off? I don't think that is enough to make any difference. Ship me out a set please... you have PM.

I ordered in a CTS-V Center and GXP center cap.
Here are the specs.

CTS-V mounting diameter 2.105"
GXP mounting diameter 2.150"

It seems you might just be able to put the pontiac center in the CTS-V wheel and use some clear silicone in the rear to hold it in.

That is how GM was fixing some Vibe centers under warranty.