Anyone try running 18x9.5 Z06 wheels on rear of GTO?

[I8COBRA]

I dont have any tires installed on mine for my vette but just threw the bare rim on the back. All 5 lugs center perfectly. The only thing is that it looked like it stuck out maybe 1" more. Would grinding my fenders be enough to run these?

[phobos512]

I can tell you that they may look centered but they aren't, it's a slightly different bolt pattern, and the things a lot of us seem to be doing with our Goats (read: racing) are not going to be kind to those wheels over the long term.

[zaracsan]

If the offset is close, the price is right and you like the style; then one could simply have the hubs re-drilled and correctly spaced lugs fitted for fairly small $$$. We have one member here that reported doing that very thing. With some of the deals that can be had with Vette take-off wheels and tires (especially the non Z06 variety) the idea may have some merrit. One idea I have considered: Is finding C6 takeoffs, ditching the spare tire (the Vette having runflats) and replacing the gas tank with a fuel cell mounted in its place; as I would really like to reclaim my trunk space.

[miscreant]

I thought Z06 wheels were 17x9.5 front and 18x10.5 rear?

[I8COBRA]

I thought Z06 wheels were 17x9.5 front and 18x10.5 rear?

Stock yes. I just received a set of 18x9.5 and 18x10.5 chrome Z06's for my vert.

As soon as I removed the lug nuts off my GTO wheels I checked out how the lugs sat in the wheels, and maybe theres something wrong with my eyes but two of the lugs did not seem centered. Took off the GTO wheel and threw on the Z06 wheel and then all 5 looked centered.

[anmracing]

That wheels offset will work. We did a test fit with the same wheel. I wouldn’t recommend the 5-120.65 on a 5-120 vehicle and we only did it to test for different offsets. The fronts won’t work at all.

[nikivee]

I can tell you that they may look centered but they aren't, it's a slightly different bolt pattern, and the things a lot of us seem to be doing with our Goats (read: racing) are not going to be kind to those wheels over the long term.

I hate to say this, but I too installed some Boyd's on my 04 GTO as a test fit and they fit perfectly. I'm not convinced a "chevy" bolt pattern doesn't work on these new GTO's. I know what my eyes saw and when I measured both bolt patterns the difference was almost nothing. We are talking .6 mm difference here. I'm not convinced any damage would occur at all.

[I8COBRA]

Well, I'm going with black Z06 wheels for my GTO. The Z06 wheel looked like it lined up better than the stock wheel, maybe I'm out of my mind but I saw what I saw. Just gotta decide if I want to go with 9.5 rears or 8.5 on all corners. The 8.5" wheels come with a 56mm offset so theyll fit perfectly.

[edgz06]

Has anyone tried to actually mount and drive with 4 Z06 rims yet?

I to want to use Z06 rims in chrome. I was even thinking of staggering them like they are on the Z06 17"s in the front and 18"s in the rear.

I miss my yellow Z06 but I need the rear seats for my kids so I'm trying to create a 4 seater Z06 so to speak.

[anmracing]

The front didn't work. So we did not.

[I8COBRA]

Not sure, but with staggering that much of a different size it might freak out the ABS. I'm sticking with all the same diameter wheels. I just realized that they make a Black ZR1 wheel in a 17x8.5" with a 56mm offset, I had those on my silver SS before and really liked the look, except they were 9.5" and 11". I might go with these instead. Heres a picture of my SS at RoadAmerica, I'll be visiting with the GTO in April :)

http://popularhotrodding.com/events/0309phr_road_a merica_22_z.jpg

[zaracsan]

For those looking in to the Vette wheel swap idea, thought I would pass along the offset info I found for the new C6 wheels.

Front wheels: 18 x 8.5 | offset 56mm | backspacing 6.95"

Rear wheels: 19 x 10 | offset 79mm | backspacing 8.61"

Stock tires: 245/40ZR18 and 285/35ZR19

[edgz06]

The front didn't work. So we did not.

Why wouldn't the fronts work?

Did you try 18" or 17"

[edgz06]

Not sure, but with staggering that much of a different size it might freak out the ABS. I'm sticking with all the same diameter wheels.


If the rims would fit, the wheel diameter issue could be addressed by using a slightly higher sidewall to compensate for the smaller rim diameter.

[I8COBRA]

For those looking in to the Vette wheel swap idea, thought I would pass along the offset info I found for the new C6 wheels.

Front wheels: 18 x 8.5 | offset 56mm | backspacing 6.95"

Rear wheels: 19 x 10 | offset 79mm | backspacing 8.61"

Stock tires: 245/40ZR18 and 285/35ZR19


I know the front would fit, but would that 10" rear fit in there?

[anmracing]

Why wouldn't the fronts work?

Did you try 18" or 17"

We did an 18" 19" staggered fitment. It rubbed hard when turning the wheels.

[I8COBRA]

Why wouldn't the fronts work?

Did you try 18" or 17"

The 9.5" is too wide for fronts, I confirmed that with my Z06 wheel. Gotta stay around a 8.5" width.

Can someone PLEASE cofirm that I can definately use a 17x9.5", 54 offset in the rear with a 275 tire?

[ZillaGTO]

I think it is nice that we may be finally getting this resolved and opening up a huge amount of wheel choices. Nikivee is well trusted and a big sceptic to boot, so I would lean towards approval or non approval. Being that you measured the difference at .6 mm does anyone have a comparison as to how big a difference that is compared to other wheels fitments?

[zaracsan]

I know the front would fit, but would that 10" rear fit in there?

The fronts may fit, but may stick out past the fender's edge a smidge. Our "tire bible" (posted elswhere here) lists a max on an 8.5" wide wheel as +48mm. The Vette wheel is 8mm more, which is only .31".

The backs would be where I would anticipate more work getting things to work correctly. We had a thread already on this, but without doing suspension modifications (like grinding on the A-arm) there is not enough room to push a 10" wide wheel inward. The bible lists a 9.5" wide fitment offset at a max of 64mm. The Vette offset is 15mm more, which converts to .59". Rolling or grinding down the lip would be a given, or even 'stretching' the lip, and (of course) flares could be done.

As wheel fitment aesthetic preferences vary; with some liking a wheel that is dead even with the fender outer edge, and others not liking that look at all. It may be possible that pushing the fitment more outboard than the bible suggests, ends up looking good to your eye, especially if the ride height is lowered a bit. The rear shocks allow for a fair amount of body roll, which makes rubbing more problematic. I am looking to upgrade to coilovers (DMS 40mm) that would allow me to run tire fitments that would otherwise rub with the OEM shocks. These replacement coilovers are adjustable as well.

If anyone has access to OEM C6 wheels, I would be interested to see what they look like mounted and where the Vette offset places the tires edge in relation to the GTO's fender lip.

[nikivee]

I think it is nice that we may be finally getting this resolved and opening up a huge amount of wheel choices. Nikivee is well trusted and a big sceptic to boot, so I would lean towards approval or non approval. Being that you measured the difference at .6 mm does anyone have a comparison as to how big a difference that is compared to other wheels fitments?

I know that this debate about bolt pattern has been going on for over a year so I won't rehash it here. What I do know is that I'm not convinced that a "chevy" bolt pattern doesn't work. I will state that it does fit with NO problems. I've test fit wheels before and just did it again today, and measured again today. I myself would have no problem buying a 4.75" wheel with proper offset and putting them on my GTO with no fear of the wheels falling off or cracking. In fact I'm going to call American Racing and see if they can get me the proper offset for the Torque Thrust II wheels and purchase a set with the 4.75" bolt pattern.

Here are some pics for you guys of my fitment test.

Pontiac 14x6 Rally II wheel on front
http://images7.fotki.com/v150/photos/4/42075/74195 9/DSC00099-vi.jpg
http://images7.fotki.com/v149/photos/4/42075/74195 9/DSC00093-vi.jpg
http://images8.fotki.com/v154/photos/4/42075/74195 9/DSC00096-vi.jpg
http://images8.fotki.com/v154/photos/4/42075/74195 9/DSC00098-vi.jpg

http://images8.fotki.com/v155/photos/4/42075/74195 9/DSC00100-vi.jpg

Boyd 17" wheels Chevy bolt pattern

http://images7.fotki.com/v149/photos/4/42075/74195 9/DSC00101-vi.jpg
http://images8.fotki.com/v155/photos/4/42075/74195 9/DSC00102-vi.jpg

http://images7.fotki.com/v151/photos/4/42075/74195 9/DSC00105-vi.jpg
http://images7.fotki.com/v152/photos/4/42075/74195 9/DSC00109-vi.jpg
http://images8.fotki.com/v154/photos/4/42075/74195 9/DSC00106-vi.jpg

lugs nuts seated 100% centered on the wheel studs.

[ZillaGTO]

that is very good "evidence" in my opinion. I am really looking forward to seeing the Torque Thrusts on your GTO.

[srice555]

What is the different of 120 and 120.65? First the different is haft or .325 mm at the lug. How thick is this?

3.25 millimeter = 0.012 inch

It's the same different as a 13mm wrench on a 1/2 bolt.

13 millimeter = 0.511 inch
0.5 inch = 12.7 millimeter

The paint on your car is thicker then different between 120 and 120.65 bolt pattern.

Four hairs on your head is thicker then this.

Three gains of sand can be stacked on top of each other in the gap, but four can't.

It's less the three sheets of 20 pound paper!

Wrapping a piece of paper only haftway around the lug will fill the gap.

You can't measure 0.3mm with a ruler.

The line made by a ball point pen is thicker!

You couldn't tell the different between a 120mm hub and a 4.75 inch hub without special tools.

Fine wire used in cutting "valuable, delicate, and fragile crystal" are 0.3mm thick.


Basicly 120mm is metric for 4.75.
I would worry more about the centric rings then the lug pattern.

[nikivee]

I agree 100%.

[Yeller Jakett]

What is the different of 120 and 120.65? First the different is haft or .325 mm at the lug. How thick is this?

3.25 millimeter = 0.012 inch

It's the same different as a 13mm wrench on a 1/2 bolt.

13 millimeter = 0.511 inch
0.5 inch = 12.7 millimeter

The paint on your car is thicker then different between 120 and 120.65 bolt pattern.

Four hairs on your head is thicker then this.

Three gains of sand can be stacked on top of each other in the gap, but four can't.

It's less the three sheets of 20 pound paper!

Wrapping a piece of paper only haftway around the lug will fill the gap.

You can't measure 0.3mm with a ruler.

The line made by a ball point pen is thicker!

You couldn't tell the different between a 120mm hub and a 4.75 inch hub without special tools.


Basicly 120mm is metric for 4.75.
I would worry more about the centric rings then the lug pattern.

Good rant but grammatically painful. :slap: I think a 120.65 wheel with a centering ring will do the trick - from experience..

[srice555]

Good rant but grammatically painful. :slap: I think a 120.65 wheel with a centering ring will do the trick - from experience..

Ya, weal I cen wrate srme gibbersh l!ke tis ard y0u'l7 unaerstoed it.


:gr_jest:

[Yeller Jakett]

Ya, weal I cen wrate srme gibbersh l!ke tis ard y0u'l7 unaerstoed it.


:gr_jest:

yES i CAN! gOOD ONE. DOH! cAPS LOCK IS ON.. :)

[edgz06]

Basicly 120mm is metric for 4.75.


This conversion chart may help. :)

120 mm converts to 4.52"

BOLT PATTERN CONVERSION mm TO inches
4X100 CONVERTS TO 4X3.94
5X100 CONVERTS TO 5X3.94
4X108 CONVERTS TO 4X4.25
5X108 CONVERTS TO 5X4.25
4X110 CONVERTS TO 4X4.33
5X110 CONVERTS TO 5X4.33
5X112 CONVERTS TO 5X4.41
4X114.3 CONVERTS TO 4X4.5
5X114.3 CONVERTS TO 5X4.5
6X114.3 CONVERTS TO 6X4.5
5X115 CONVERTS TO 5X4.52
5X120 CONVERTS TO 5X4.52
5X120.7 CONVERTS TO 5X4.75
5X127 CONVERTS TO 5X5
6X127 CONVERTS TO 6X5
5X135 CONVERTS TO 5X5.3
6X135 CONVERTS TO 6X5.3
5X139.7 CONVERTS TO 5X5.5
6X139.7 CONVERTS TO 6X5.5
5X150 CONVERTS TO 5X5.9

[srice555]

This conversion chart may help. :)

120 mm converts to 4.52"

BOLT PATTERN CONVERSION mm TO inches
5X115 CONVERTS TO 5X4.52
5X120 CONVERTS TO 5X4.52

:sneaky:

115 != 120

[nikivee]

120mm=4.72"
120.6mm=4.75"

[srice555]

Found something else equal to 0.3mm.

The blue lines on notebook paper are about 0.3mm!!

[edgz06]

:sneaky:

115 != 120

Woops! small typo there. :confused:

[anmracing]

So would it be ok to put heads on an engine if the bolt holes didn’t line up with the block by only .65mm??? :gr_jest:

[BobthePhotoGuy]

How about this.

Can someone find out what the typical tolerance is when the wheels are drillied?

and also when the rotors are drilled?

Bob