I'm going to widen my rear rims.

[99-LS1-SS]

I was debating between 9.5" or 10". I do not want to roll the fender if I go with 10". I've all but decided to go with 9.5" and I have a safety question. I can get 1/4" or 3/8" spacers and guarantee no rubbing in the inside of the rim. 3/8" would put me almost exactly the same offset as the stock 9.5" Clubsport R8 rims. I would like to go with the 3/8" spacer but not at the expense of safety. Will 3/8" spacers be too much for the stock lug nuts and studs? Thanks.

[99-LS1-SS]

Bump.

[r33pwrd]

there are a buch of TBSS guys that did this... let me look and see what I can find out.

[GRRRR8]

After all I am going through to fit my drag wheels, 3/8 wont leave enough stud. I didnt need spacers and the studs were not "safe" in my book.

[99-LS1-SS]

How much are studs and how big of a pain in the ass are they go swap out?

[GRRRR8]

Rears are a huge pain in the ass! I went to smaller diameter for my wheels, but Crazy Paul gave me an OZ company that had the same studs in our car that were 2.74 if I recall. The spindles will have to be removed and the hub pressed out to get the studs out.

[99-LS1-SS]

Rears are a huge pain in the ass! I went to smaller diameter for my wheels, but Crazy Paul gave me an OZ company that had the same studs in our car that were 2.74 if I recall. The spindles will have to be removed and the hub pressed out to get the studs out.

That figures....

[Crazy Paul]

Rears are a huge pain in the ass! I went to smaller diameter for my wheels, but Crazy Paul gave me an OZ company that had the same studs in our car that were 2.74 if I recall. The spindles will have to be removed and the hub pressed out to get the studs out.

What did you measure the knurl dia and shoulder length of the stock studs as ?
So I'll know the full story for next time somebody asks.

:)

[r33pwrd]

how about the bolt on spacers?

[-Ray-]

If you remove 3/8" from the factory studs, you are removing 9 1/2 turns from the lug nut.
That's considering a 14x1 mm stud.
Check with a standard metric lg nut, and see how much stud is left.
Or, mark 1 side of one of your lug nuts, and break it loose and count the amount of turns till completely off.

[99-LS1-SS]

How many should I have left to be safe Ray?

[-Ray-]

Since the lug nut is a blind hole, we can't see how deep it goes. Easier just to get a standard metric lug nut and see where it is. I don't know the current length of our lug nuts, so don't know how many turns.
Wait. LOL I've never taken off my lug nuts. Maybe I should just pull off a plastic cap and check. I'm an idiot. LOL

[-Ray-]

After looking at it, you won't be able to space the wheels out more than 1/8"

[99-LS1-SS]

That's what I was afraid of....dammit. Charlie, when you have a spare moment pick me up some longer wheel studs and drive up here and help me change them out real quick! LOL!

[GRRRR8]

I wish! Also dont forget we have starter studs, so the 1st 1/4 inch or so is not even threaded.

[-Ray-]

I wish! Also dont forget we have starter studs, so the 1st 1/4 inch or so is not even threaded.

Yep, there is a lead thread left beyond the lug nut. That's it.
Off to look at a GXP.

[r33pwrd]

this is what you need..........

http://www.2kracing.com/Product/20537.html

[GeorgeInNePa]

this is what you need..........

http://www.2kracing.com/Product/20537.html

That's an inch thick.

[r33pwrd]

That's an inch thick.

I know I was trying to say this syle is what would work best...

[99-LS1-SS]

What BMW lug pattern is the closest to the G8?

[r33pwrd]

What BMW lug pattern is the closest to the G8?

all 5x120 but the center hub will be different im sure...

[-Ray-]

What BMW lug pattern is the closest to the G8?

You mean offset? 3 series I thought.

[99-LS1-SS]

No I mean lug pattern. I've got the offset in mind that I want to achieve. I can't find spacers with studs attached for GM or Pontiac but I'm finding a lot for BMW's. I think most of the BMW's have 5x120 lug pattern. The X5 has the 5x120 with 14x1.5 lugs. What is the thread pattern on our studs?

[-Ray-]

5X120
14 mm studs.

[r33pwrd]

5X120
14 mm studs.

the BMW spacers will bolt up assuming the center hub diameter is the same... looking at my car tonight I think a 1" spacer would work... and than add 2" to the inner side of the weel...

[99-LS1-SS]

the BMW spacers will bolt up assuming the center hub diameter is the same... looking at my car tonight I think a 1" spacer would work... and than add 2" to the inner side of the weel...

Exactly.

[-Ray-]

You can add a 1" spacer after you replace all the studs for longer ones.

[99-LS1-SS]

I probably wouldn't go a full inch. I'm thinking 1/2 inch and I'll still have to replace the studs. I know it will be worth it once it's done but it will be a pain in the ass doing it.

[GeorgeInNePa]

I probably wouldn't go a full inch, but it will be a pain in the ass doing it.


That's what she said!

[99-LS1-SS]

That's what she said!

http://icanhascheezburger.files.wordpress.com/2008/06/funny-pictures-oh-my-kitten.jpg

[GeorgeInNePa]

http://img.photobucket.com/albums/v320/GeorgeInNePa/Comedy/omg_wtf_cat.jpg

[r33pwrd]

You can add a 1" spacer after you replace all the studs for longer ones.

not if you use the spacers hown a few posrts back that bolt on...

[locrzn#92]

You shouldn't have any problems with 9.5, there is lots of clearance on the inside. Don't run a spacer on these fast cars and definetly don't run a bolt on. We've been thru this, very hard to keep the rear from shaking. You can't balance the spacer and wheel together, if the spacer is not made perfectly you'll have problems from the getgo. We've sold the billit spacers in the past, very good looking pieces and fine for show cars and trucks, not for drag racing and expensive as hell for the good ones. I have 9.5's and 43mm off set, not an issue. Good luck.

[Roadrunner 45]

I just went through this. Stock 19's have 1.75" clearance from inside wall of tire to body. I really wanted to widen the wheel to 9.5", but with a 285 series rear tire that would leave zero clearance without a spacer. I could have then put in a 1/2" spacer to bring the outer wall flush with the top of the wheelwell, but the body tapers in from the topmost point, so I thought that it would look funky.
Ended up sending the wheels out for a 1" widen, and will run a 275 tire. Will snap pics when I get the wheels back. should have just under 1/2" clearance to the inner wall of the trunk.

[r33pwrd]

I just went through this. Stock 19's have 1.75" clearance from inside wall of tire to body. I really wanted to widen the wheel to 9.5", but with a 285 series rear tire that would leave zero clearance without a spacer. I could have then put in a 1/2" spacer to bring the outer wall flush with the top of the wheelwell, but the body tapers in from the topmost point, so I thought that it would look funky.
Ended up sending the wheels out for a 1" widen, and will run a 275 tire. Will snap pics when I get the wheels back. should have just under 1/2" clearance to the inner wall of the trunk.


Very cool! I want to do this as well please keep us updated on the progress of them!

[rumbler]

I'm a noob here but have lurked much. I'm waiting for a deal on a gxp and I too intend to widen stock 18's to carry 285's in rear(no 19's for me).
I've done alot of searching on this matter and will go with 9.5 wide.

If the point of contact would be the trunk wall, couldn't the trunk wall be persuaded a little? Nobody do this? A piece of 2x4 and a sledge(don't miss!!) and voila.

Rumbler

[Roadrunner 45]

On the pass. side, the fuel fill line is just about flush with the trunk wall too. I did consider either "massaging" the trunk wall and relocating the fuel line, or cutting out the section of the trunk wall where it bows in and adding a flat steel plate (a pseudo-mini tub). Either way, it looks like the fill line would have to be moved a little. There's probable other ways around this, but I didn't want to turn it into a project.

[rumbler]

I'm still looking for a solution. . . .

Maybe these would work. According to you guys 3/4 may be a bit much tho. Anyways, how bad can 285/40's be with 18x9?

http://www.skulte.com/product_info.php/cPath/21/products_id/84

Rumbler

[Roadrunner 45]

1/2" spacer on the stock 19 x8 with the 245 tire will put tire sidewall almost exactly flush with top of rear wheelwell. The factory 245 tire on the 8" rim has a sidewall that is larger than the rim by .45" per side (per the manufacturer, when I measured, I got slightly less which didn't make much sense to me).
A 285 tire on a 10" rim will have a section that is approx .65" wider than the rim (per side, according to bridgestone). It should be slightly narrower ( about .55" section overhang per side) on a 9.5" wide rim - which is the widest you can go in this case .

So if we know that the factory 245 will be flush with outer edge with a 1/2" spacer, going with a 285 on a 9.5" rim with a 3/4 spacer means you'd be sticking out of the wheelwell by about .35".

You could try the same setup with a .300" thick spacer, but you'd have to put in longer wheel studs. That would give you just about .300"- .400" clearance from the inner sidewall to the trunk on a non-lowered car. That is a bit tight for my taste, and may cause a problem in hard cornering (but it may be ok too), but I didn't want to chance it since once the wheels are modded, the $$ has been spent- and I also didn't want to beat in the inner wheelwell on my new car.

but...don't take my word for it, get a straight edge and a ruler and take some measurements.

[99-LS1-SS]

I'm a noob here but have lurked much. I'm waiting for a deal on a gxp and I too intend to widen stock 18's to carry 285's in rear(no 19's for me).
I've done alot of searching on this matter and will go with 9.5 wide.

If the point of contact would be the trunk wall, couldn't the trunk wall be persuaded a little? Nobody do this? A piece of 2x4 and a sledge(don't miss!!) and voila.

Rumbler

The GXP only comes with 19's. If you are going to spend the extra money on a set of 18's then you might as well search for the correct offset. For a 9.5" rim you'll want at least 50mm offset if you go 10" you'll need 57mm offset.

[Roadrunner 45]

I WILL post picks when I get everything done, so then you can see for yourself.

[99-LS1-SS]

1/2" spacer on the stock 19 x8 with the 245 tire will put tire sidewall almost exactly flush with top of rear wheelwell. The factory 245 tire on the 8" rim has a sidewall that is larger than the rim by .45" per side (per the manufacturer, when I measured, I got slightly less which didn't make much sense to me).

So if we know that the factory 245 will be flush with outer edge with a 1/2" spacer, going with a 285 on a 9.5" rim with a 3/4 spacer means you'd be sticking out of the wheelwell by about .35".


Are you talking about an aftermarket rim or widening the factory rim? The reason I ask is that if you widen the factory rim it will have to be widened towards the inside of the rim. There isn't enough material to widen towards the outside. If you have the factory rim at 8" wide and you add 1.5" to the inside but don't add a spacer the rim will not stick out any further than stock but it will rub on the inside. You will have to add a spacer to move the rim away from the inner fender well.

The factory 8" rim has an offset of 48mm. (1" = 25.4mm) The factory 9.5" rim (Holden rims) has an offset of 57mm. That is 9mm difference which equals .35" which is a hair above 1/3". So given these facts, you really only need a 3/8" spacer to put a factory rim, that has been widened 1.5" to the inside, in line with the factory Holden 9.5" rims which should have an acceptable amount of clearance.

If you are talking about buying a set of aftermarket rims then disregard this post and look for around 55mm offset.

[Roadrunner 45]

yes, widening the stockers.

[nino@gaypontiac]

Why not just go with a set of CTS-V wheels? My cost they only run about 1300 for the rear pair and they ar 9.5"

[SRG963]

Why not just go with a set of CTS-V wheels? My cost they only run about 1300 for the rear pair and they ar 9.5"

How much do they weigh?

Personally, I refuse to purchase anything that is more than stock.

[GeorgeInNePa]

Why not just go with a set of CTS-V wheels? My cost they only run about 1300 for the rear pair and they ar 9.5"

No offense, but there are a lot of nice 9.5s out there that are less than $1300 for 2.

[SRG963]

No offense, but there are a lot of nice 9.5s out there that are less than $1300 for 2.

lol, the set I'm about to pull the trigger on is $800, that's for all 4! The rears are 27 pounds, fronts 20.6 pounds

[r33pwrd]

Are you talking about an aftermarket rim or widening the factory rim? The reason I ask is that if you widen the factory rim it will have to be widened towards the inside of the rim. There isn't enough material to widen towards the outside. If you have the factory rim at 8" wide and you add 1.5" to the inside but don't add a spacer the rim will not stick out any further than stock but it will rub on the inside. You will have to add a spacer to move the rim away from the inner fender well.

The factory 8" rim has an offset of 48mm. (1" = 25.4mm) The factory 9.5" rim (Holden rims) has an offset of 57mm. That is 9mm difference which equals .35" which is a hair above 1/3". So given these facts, you really only need a 3/8" spacer to put a factory rim, that has been widened 1.5" to the inside, in line with the factory Holden 9.5" rims which should have an acceptable amount of clearance.

If you are talking about buying a set of aftermarket rims then disregard this post and look for around 55mm offset.


Good info! I personally love the idea of a wider rear OEM wheel... I also love the idea of a big lip...

[nino@gaypontiac]

Which of those cheapo sets are fully forged and match the factory wheels for those people that prefer the stock look maybe?

It was just a suggestion in opposition to widening the stockers and using spacers.

[r33pwrd]

Which of those cheapo sets are fully forged and match the factory wheels for those people that prefer the stock look maybe?

It was just a suggestion in opposition to widening the stockers and using spacers.

It would be cool but very expensive! I think most would rather have aftermarket for that kind of money (2600 bucks can buy a nice set of aftermarket wheel)...

widining the wheels is pretty cheap and the most expemsive part is a new set of rear tires.

[Roadrunner 45]

FYI: Widening = $225/wheel. I should have them back late next week.

[rumbler]

Hey Roadrunner,
It may be too late for you but would it be feasible for the seats of the wheel holes to be modified(drilled) to remove the taper? If the seats were flatter and deeper a different lug nut could be used to allow more thread engagement. If you got more thread engagement you could use the spacers and go with 9.5" wide without changing studs.

Rumbler

[Roadrunner 45]

I looked at machining the tapers deeper to avoid longer studs. I don't have the wheels here now to double check, but as I recall, the thickness of the pad at the intersect of the seat to the lug bore was 1/2". I did consider making spacers, and then machining the lug taper to a greater depth- leaving .300" or so at the intersect, but I have no way to calculate how much load a thinner lug pad would hold with the wheel being a casting. I didn't want to risk cracking off the wheels on a hard turn, so I opted not to do it.

It is definitely an option if you are just dying to go 9.5" wide with a 285 tire, but I didn't feel an extra cm of tire width was worth the risk and effort. I'd like to see someone try it, but I don't want to be the first.

[rumbler]

we're thinking alike, but I was thinking along the lines of a flat seat(no taper) and using shank style nuts. This would leave the lug pad thickness @ the same 1/2". It "shouldn't" compromise strength but I wouldn't want to be first either LOL. As it is I,m waiting to see YOUR results.
Rumbler

[99-LS1-SS]

I wonder how hard it would be to add material to the pad? Maybe a 1/3"...

[r33pwrd]

I wonder how hard it would be to add material to the pad? Maybe a 1/3"...

just do spacer than.....

[c5racr1]

great thread, a lot of us are watching with great intrest !

[WhiteDeathLSX]

Im also doing this with my GXP wheels. They go to the machine shop next weekend. Im going to 9.5" width... :)

[Mlozano]

So if you went this route, you would need spacers for sure, right?

[Roadrunner 45]

got them back- quality! but the site won't take the pics, i guess i have to resize. will post pics tonight.

[nino@gaypontiac]

Im curious, if its 225/wheel for wideing, plus spacers, plus studs, plus labor.

Why not just get the CTS-V wheels and have a solid OEM piece with the correct offset for the 570/wheel?

I would have to think the stockers are worth 200-250 each anyway on the open market for people wanting spares.

[r33pwrd]

Im curious, if its 225/wheel for wideing, plus spacers, plus studs, plus labor.

Why not just get the CTS-V wheels and have a solid OEM piece with the correct offset for the 570/wheel?

I would have to think the stockers are worth 200-250 each anyway on the open market for people wanting spares.

How much is 4 CTS-V wheels and tires?? that should answer your question....

[KaiserM715]

Why not just get the CTS-V wheels and have a solid OEM piece with the correct offset for the 570/wheel?


How much is 4 CTS-V wheels and tires?? that should answer your question....

I would love to hear more about how much the CTS-V setup would be. It sounds like they are the same bolt pattern as the G8, can anyone verify?

[Greg@PacePerformance]

The CTS-V wheels are about 500.00 each new Just an FYI.

[r33pwrd]

The CTS-V wheels are about 500.00 each new Just an FYI.

So 2K for wheels VS $550 plus spacers for widening ... IMO For 2K I will take a set of aftermarket wheels!

[G8GXP4now]

How would it look with 2 CTS-V rears and 2 GXP fronts?

[Greg@PacePerformance]

Not good since they are not the same wheel as per nine ball's post (http://forum.grrrr8.net/showthread.php?t=5284)

[p71]

It is the same bolt pattern... I belive nino is looking to run this setup on his personal GXP. I personally may be holding on for a little bit until camaro spec wheels come out cause... well those should fit to right?

[nino@gaypontiac]

I thought he was only widening the 2 rears.

2 CTS-V rear wheels would run 1140 with taxes and all for my cost.

Thats 640 more than widening, true. But what about the studs? Labor? and the fact that you can resell your stock wheels and have rear wheels that were not cut, rewelded?

Not saying its unsafe, but I recall the Marauder crew used to do this alot and it is very visible and to me, that is just not attractive. For what could essentially be a very small difference in cost I think the CTS-v wheel is a better bargain. Running spacers scares the crap out of me.

[r33pwrd]

I thought he was only widening the 2 rears.

2 CTS-V rear wheels would run 1140 with taxes and all for my cost.

Thats 640 more than widening, true. But what about the studs? Labor? and the fact that you can resell your stock wheels and have rear wheels that were not cut, rewelded?

Not saying its unsafe, but I recall the Marauder crew used to do this alot and it is very visible and to me, that is just not attractive. For what could essentially be a very small difference in cost I think the CTS-v wheel is a better bargain. Running spacers scares the crap out of me.

so your saying to have non matching wheels front and back?? dont let adapters scare you... spacers maybe but not well built adapters (the bolt on ones)

[99-LS1-SS]

got them back- quality! but the site won't take the pics, i guess i have to resize. will post pics tonight.

You have a PM.

[r33pwrd]

got them back- quality! but the site won't take the pics, i guess i have to resize. will post pics tonight.

e-mail them to me bradw@ecsrep.com I can post them

[nino@gaypontiac]

As far as I can tell, they do match

This is why I wanted to get the CTS-V rears.

[r33pwrd]

As far as I can tell, they do match

This is why I wanted to get the CTS-V rears.

This is where the confusion comes in... So the thread started off with a GXP owner than turned to a GT owner (with 19's) I have been talking 19" GT wheels for the past few posts... I was starting to think you where crazy :) but on a GXP yes is looks like you could use the CTS-V wheels but NOT with the GT 19" wheels as it would look a little funny.

[99-LS1-SS]

As far as I can tell, they do match

This is why I wanted to get the CTS-V rears.

Nino, they are not the same. There are subtle differences. Here is a picture of each of them. Pay attention to the lip where the valve stem mounts.

It's "notched" on the CTS-V
http://z.about.com/d/cars/1/0/r/A/1/09_ctsv_wheel.jpg

And "rounded" on the GXP.
http://www.planetlsx.com/images/articles/49-7.jpg

[99-LS1-SS]

got them back- quality! but the site won't take the pics, i guess i have to resize. will post pics tonight.

Here are the images.

http://www.usamls.net/brandon/images/img_0225sm.jpg

http://www.usamls.net/brandon/images/img_0226sm.jpg

[r33pwrd]

looks good.

[Mlozano]

So they cut then reweld an extra piece?

[Mlozano]

What's the update, did you get them to fit

[Roadrunner 45]

yep. they fit by a MILE. It's kind of good and bad. When you look at the car it looks better, but you can't tell exactly why. You wouldn't look and be like- "ooh, he widened the rear wheels". There's about an inch more rubber in the back, but unless you really look, it's hard to tell. I haven't measured yet, but just with my fingers, it seems like I could have easily went to 9.5" wide and run a 285 tire with just a 3/16 spacer.

[ro9beam2002]

if using the rear cts-v wheels on the back of a g8 gxp.. do you come close to being with the rear fender lip? if so what size tire? how much wider overall will it be in the rear vs stock?

[nino@gaypontiac]

I have CTS-V rears with stock CTS-V Michelin 285's.

Im not even remotely close to the fender. There is room for 305's if I could find a set that I liked.