GTO Wheels

[CARGUY]

Looking for technical specs on GTO wheels.

Has anyone found the width, offset, bolt circle, and lug size
of the wheels that will be on the GTO?

I am looking to swap out the wheels quickly.
I don't want to take any wheel seller's word on the correct
size.


Impulse Blue/Blue MN6 on order
Anticipation is great.

Carguy in Michigan.

[Tails]

Dang,
The tires are 245/45ZR17 KDWS. I remember somewhere in one of this forums some one posted that other stuff. They will come by and answer eventually or you can look through all the posts.

:drink: :drink: :drink: :drink:

[CMNTMXR57]

All that stuff was tire size I believe. I don't know any of the specs on the wheels. I wouldn't bet the house on it, but my guess is that they aren't too far off the 18's used on Vette's and on a standard Chevy 4.5" (or is it 4.25") bolt pattern. I can never remember.

[nasa43]

I asked about the Monaro wheels on NewAgeGTO and a guy posted the following:

5 lug
Offset: 35.42
PCD: 120mm

[CMNTMXR57]

Ok, for those of us that don't prescribe to the metric system, I went and converted them

35.42mm = 1.39449"
120mm = 4.72441"

[nascarteachr]

All that stuff was tire size I believe. I don't know any of the specs on the wheels. I wouldn't bet the house on it, but my guess is that they aren't too far off the 18's used on Vette's and on a standard Chevy 4.5" (or is it 4.25") bolt pattern. I can never remember.
5x4 3/4 is the spacing.

[nascarteachr]

5 x 4 3/4 is chevys pattern, 5 x 4 1/2 is fords.

[Snafu]

If you go over to the wheels/tires section or do a search there's a ton of info.

5x120 does not equal 5x4 3/4...yes some have bolted them up, but it's not advisable to run them all the time...in other words, don't use fbody wheels

make sure the wheel is hub-centric and not just lug-centric...the weight of the car should be resting in the hub, if it's on the lugs, you're in for an accident

[trm100]

If you go over to the wheels/tires section or do a search there's a ton of info.

5x120 does not equal 5x4 3/4...yes some have bolted them up, but it's not advisable to run them all the time...in other words, don't use fbody wheels

make sure the wheel is hub-centric and not just lug-centric...the weight of the car should be resting in the hub, if it's on the lugs, you're in for an accident

Is there any reason not to remachine the taper for the nuts to an actual 120mm bolt pattern so people don't have to throw out f-body rims or not have the option of buying other new 120.65 rims? Christ, you only have to move the bolt pattern in about .013 radially. I figure you would have to drop the taper down about another .030 at the new location to ensure full engagement on the 120mm pattern. Yes, I are a machinist with a PHD (push here dummy).

[CSiJason]

5x120 bolt spacing, 48mm offset (stock 17x8's), 69.5mm center bore

Do a search in this forum for info on what you should use for wheel offsets for different size/width wheels and tires without having rubbing issues or a froggy looking retard car.

[sccaGTO]

5x120 bolt spacing, 48mm offset (stock 17x8's), 69.5mm center bore

Do a search in this forum for info on what you should use for wheel offsets for different size/width wheels and tires without having rubbing issues or a froggy looking retard car.
This info will come in VERY handy. Thanks, Jason.

[CSiJason]

This may be even more handy...

WIDTH..........OFFSET............WIDTH OF TIRE
7.0...............+26/+65.............215/225/235
7.5...............+33/+61.............215/225/235/ 245
8.0...............+39/+55..............225/235/245
8.5..............+45/+48..............235/245/255
9.0.(MAX).........+48................245/255
REAR ONLY
8.0................+36/+65.............245/255
8.5................+42/+65...............245/255
9.0.................+48/+65...............255/265/ 275
9.5................+55/+64...............265/275/2 85

OFFSETS GREATER THAN SHOWN ABOVE WILL RUB ON REAR
FENDER LIP. (25MM FENDER LIP)

[xom]

This may be even more handy...

WIDTH..........OFFSET............WIDTH OF TIRE
7.0...............+26/+65.............215/225/235
7.5...............+33/+61.............215/225/235/ 245
8.0...............+39/+55..............225/235/245
8.5..............+45/+48..............235/245/255
9.0.(MAX).........+48................245/255
REAR ONLY
8.0................+36/+65.............245/255
8.5................+42/+65...............245/255
9.0.................+48/+65...............255/265/ 275
9.5................+55/+64...............265/275/2 85

OFFSETS GREATER THAN SHOWN ABOVE WILL RUB ON REAR
FENDER LIP. (25MM FENDER LIP)



Ahhh the offset Bible.
I was wondering when that would show up again.
Spent many a website searching with that.....and found crap :(

[sccaGTO]

This may be even more handy...

WIDTH..........OFFSET............WIDTH OF TIRE
7.0...............+26/+65.............215/225/235
7.5...............+33/+61.............215/225/235/ 245
8.0...............+39/+55..............225/235/245
8.5..............+45/+48..............235/245/255
9.0.(MAX).........+48................245/255
REAR ONLY
8.0................+36/+65.............245/255
8.5................+42/+65...............245/255
9.0.................+48/+65...............255/265/ 275
9.5................+55/+64...............265/275/2 85

OFFSETS GREATER THAN SHOWN ABOVE WILL RUB ON REAR
FENDER LIP. (25MM FENDER LIP)
:hail: You're right. That is handier. Are all of these measurements that have been tested? If they are, you saved me a sh*tload of work & calculation.

[CSiJason]

This was determined by the folks at discounttiredirect.com I do believe.

[sccaGTO]

This was determined by the folks at discounttiredirect.com I do believe.
Works the same, I suppose. They have the free time to swap out different combos.

[-=RampageRed2K5=-]

I need hub rings any one know a after market site that I can order 69.5 to 72mm hub rings :bomb: need some soon.Here some pic's

[speed_demon_freak]

http://www.ls1gto.com/forums/faq.php?faq=new_faq_i tem13#faq_new_faq_item15



I certainly can’t list all the ones we’ve found to fit – but the answer is not as many as you think. The offset is European. The GTO hub has a 5x120.00mm bolt circle diameter. The offset is 48 mm for both 17-inch and 18-inch wheels. The GTO wheels have 8.0 inch wide rims.

[jzr]

This may be even more handy...

WIDTH..........OFFSET............WIDTH OF TIRE
7.0...............+26/+65.............215/225/235
7.5...............+33/+61.............215/225/235/ 245
8.0...............+39/+55..............225/235/245
8.5..............+45/+48..............235/245/255
9.0.(MAX).........+48................245/255
REAR ONLY
8.0................+36/+65.............245/255
8.5................+42/+65...............245/255
9.0.................+48/+65...............255/265/ 275
9.5................+55/+64...............265/275/2 85

OFFSETS GREATER THAN SHOWN ABOVE WILL RUB ON REAR
FENDER LIP. (25MM FENDER LIP)Do these numbers apply to stock or rolled fender lips?
I'm wondering how much could be fit up front with a heavily rolled fender lip, custom coilovers to get the perch out of the way on the inside, and maybe camber plates if anybody ends up making some.

Right now I think a wide 265 on an 18x10 rear looks doable, and the same 265 pinched on an 18x9 could perhaps be made to work up front, with enough negative camber...??

[sccaGTO]

Damn, JZR, don't be greedy on the tire size. 18"x10" in the rear may still require notching the control arm in the rear. an 18x9 in the rear with a 265 tire will work fine. A 265 on a 10" wide rim will make the tire look too small for that rim. A 265 on front may be out of the question. Some people are having problems fitting 245s on front. I'd say a 245 for the front would be the limit.

Rampage, PM CSiJason. He has or can have made some of the hubcentric rings for that combo.

[jzr]

Damn, JZR, don't be greedy on the tire size. 18"x10" in the rear may still require notching the control arm in the rear. an 18x9 in the rear with a 265 tire will work fine. A 265 on a 10" wide rim will make the tire look too small for that rim. A 265 on front may be out of the question. Some people are having problems fitting 245s on front. I'd say a 245 for the front would be the limit.
Doesn't it come with 245's stock? Surely there's room for improvement there. With a 25" tall tire, each degree of negative camber we get moves the top of the tire inboard about .2". So if we could get some camber plates in there with 3* or more of negative camber, we could theoretically gain .6" or more of outboard clearance. Combined with an aggressive fender roll, I think a 265 on a 9" rim would work.

The 265s I run (Yokohama Advan Neova AD07) are pretty wide though, wider and with a squarer shoulder than the 275 Falken RT-615. They fit pretty well on a 10" rim though:
http://user.gofastlab.com/jzr/DSC00166.JPG
If there was room, would work even better on a 10.5". I'll have to look at the rear control arms, see how bad an interference issue they might be.

Oh, and I'm just contemplating building a GTO for the SCCA's Solo2 STU class. Presently I'm campaigning a Lexus IS300 there (the car in the pic) - it handles well, but is lacking in power. The GTO should be able to make 200 more hp, but it'll also be about 500lbs. heavier after lightening to the limit of the rules. The Lexus can only fit 235s up front, so I figure if I can get 265s on the front of the GTO, it might have a chance.

[sccaGTO]

Ah, but with negative camber comes inner fender clearance problems & accelerated tire wear. You would have better results notching those rear control arms. Most of us that are running 9"s in the rear feel that they are enough for moderate acceleration. On the front tires, 245s come stock, but the 18" factory wheels come with 235s on front. I even run a 275 in the rear. Now, with Koni shocks, I don't have fender rub.

Notice your picture? The rim guard is supposed to go out farther than the rim, not even with it. That's why a 275 is a better fit for a 9" rim instead of a 10" rim.

[miscreant]

Doesn't it come with 245's stock? Surely there's room for improvement there. With a 25" tall tire, each degree of negative camber we get moves the top of the tire inboard about .2". So if we could get some camber plates in there with 3* or more of negative camber, we could theoretically gain .6" or more of outboard clearance. Combined with an aggressive fender roll, I think a 265 on a 9" rim would work.

The 265s I run (Yokohama Advan Neova AD07) are pretty wide though, wider and with a squarer shoulder than the 275 Falken RT-615. They fit pretty well on a 10" rim though:
http://user.gofastlab.com/jzr/DSC00166.JPG
If there was room, would work even better on a 10.5". I'll have to look at the rear control arms, see how bad an interference issue they might be.

Oh, and I'm just contemplating building a GTO for the SCCA's Solo2 STU class. Presently I'm campaigning a Lexus IS300 there (the car in the pic) - it handles well, but is lacking in power. The GTO should be able to make 200 more hp, but it'll also be about 500lbs. heavier after lightening to the limit of the rules. The Lexus can only fit 235s up front, so I figure if I can get 265s on the front of the GTO, it might have a chance.

1) You can't roll the front fenders much more than they are already rolled up. That's not the issue anyway.
2) You can't go more than about -1.8 to -2.0 negative camber, or you hit the strut BODY. Coil overs won't help they actually hurt because the stock strut body is only about 2 1/2"-3" in diameter, and even the factory 245/45 in stock offset hits the strut. Most coil overs, even the smaller ones, are larger in D than that.
3) You're tire above can't possibly be giving you the best performance. The side wall reinforcements are not perpidicular to the ground. IMHO, if you put those 265s on a 9" rim, you'd get better roll resistance and rear end control. You can almost SEE the bead on those things, and as stated above the rim protector which is designed to protect the rim, is not protecting the rim :eek: Putting a 265 on a 10" rim is way overkill, and thinking 10.5" is rediculous.

[An aside : What's with everyone lately wanting to put too small of a tire on too wide of a rim?????]

You don't need more than 245 in the front. Because of the power in the GTO, your most important factor is balancing the rear. In fact, you'd want a little smaller meat in the front. If you rolled the fenders in the rear, got a nice aggressive 9.5" wheel with 275s in the rear, put 245s up front, and installed a good adjustable sway kit, you could dial in a completely neutral car very easily, even with all the HP and TQ going to the ground. Use the adjustments of the sways to bring the car into balance, and keep the smaller meat up front for turn in and response.

[sccaGTO]

2) You can't go more than about -1.8 to -2.0 negative camber, or you hit the strut BODY.

[An aside : What's with everyone lately wanting to put too small of a tire on too wide of a rim?????]
I forgot that the shock sits inside the fender & would be the first thing to rub. D'OH!

And, on the aside: I suppose either people are trying to be different or they have tire envy. :gr_jest:

[jzr]

Guess I should say I'd only run the big wheels/tires for "big time" autocross competition, and run around on the stockers on the street. The CCW in the pic is the present car's race wheel. For the GTO I'm looking at designing a package that maximizes performance on a typical tight and twisty autocross course.

Seems like with a 2.5" (or even better, 2.25") sprung coilover, you could move the top of the strut inboard a good ways, with a camber plate or offset strut top hat or whatever. Being a strut car, I'm guessing the GTO will need at least 3-3.5 degrees static negative camber up front to work best. I think with a nice stiff and short 6" spring, the lower spring perch would be up and out of the way of the tire. Haven't seen a good coilover setup for the car yet, anybody in the 'States producing one?

In my experience negative camber only wears tires when combined with a large toe setting. I have/would run 0 toe up front - even with the large camber setting, tire wear isn't really any greater.

The car would probably put power down better with a 9" rear wheel, but the main goal (for me) would be getting around corners as fast as possible.

miscreant, putting a given tire on a wider wheel will tend to "stretch" more rubber onto on the ground over a wider area, providing a better contact patch for cornering. Generally, putting a tire on the widest wheel it can accomodate will net the most cornering performance from that tire. The tire I run (http://www.tirerack.com/tires/tires.jsp?tireMake= Yokohama&tireModel=ADVAN+Neova+AD07) specifies a 9-10.5" rim width range (http://www.tirerack.com/tires/Spec.jsp?make=Yokoh ama&model=ADVAN+Neova+AD07).
Of course you're free to not agree. If you'd like to research further, I can recommend a couple good books on the subject of tires and their performance:
Paul Haney's Racing & High Performance Tire: Using Tires to Tune for Grip and Balance (http://www.amazon.com/exec/obidos/tg/detail/-/0768012414/qid=1115777833/sr=8-1/ref=sr_8_xs_ap_i1_xgl14/002-0030489-5030470?v=glance&s=books&n=507846)
and the ubiquitous Race Car Vehicle Dynamics (http://www.amazon.com/exec/obidos/tg/detail/-/1560915269/ref=pd_sim_b_1/002-0030489-5030470?%5Fencoding=UTF8&v=glance) by Milliken & Milliken.

A 245 is not much tire to turn a 3500+lb. 55/45 car, I'd say it's about right for a car 1000 pounds lighter than a GTO. Still, I'm limited to a 275 in the class I want to race in, want as much of that as I can get at each corner to get the pig through the slaloms and tight stuff. Gotta keep up with the E36 M3s and the Evos!

Are people having inner fender clearance issues stock? And is it the fender liner or the fenderwell itself that rubs?

[sccaGTO]

Remember, running a 265/275 on the front is also gonna take more effort by the steering rack to turn. In heavy switchbacks on the auto-x, the fluid may get hot enough not to turn as quickly as you want. Also, each tire has a recommended width & an approved range of widths. Running the widest tire on the widest rim available is not always the best answer.

[jzr]

I saw one guy boiled his fluid at the track, C4s used to do that all the time. Fortunately autocross runs are generally short with plenty of cool-down time between.

I don't think the effort will be a problem with street tires, with R-compounds or slicks, maybe.

sccaGTO, do you do SCCA autocross events with your car?

[sccaGTO]

I haven't yet, but the thought has crossed my mind many times. I auto-xed my '97 S10 2wd before & the steering gear & fluid got hot on one of the runs & it delayed the actual moment of turning. Turn wheel, kill cones, truck turns. :gr_jest: :banghead:

If you are allowed to run R-compound tires in your class, get info on experiences from other drivers running F-bodies. Those drivers are pushing ill handling cars through the cones & they have had many years to figure out how to run them & what tires to use. I used Kumho Ecsta V700 tires when I auto-xed my Miata. I like those. The Kumho Ecsta V710 looks like a race slick with 2 grooves going around the tire. I'd think those would work better than the V700.

[vice86]

GroupA wheels says the stock GTO offset is +48

[jzr]

The Kumho Ecsta V710 looks like a race slick with 2 grooves going around the tire. I'd think those would work better than the V700.Yup, the V710 is a fantastic tire, I have a little experience on them:
http://user.gofastlab.com/jzr/SM2vette.jpg
They really start to blur the line between a DOT-R and a slick.

I think the GTO would be fun in F-Stock on 710's, but with its heft and 245 tire size limitation I don't think it'll keep up with the Mach 1 on 275s, which I have driven a bunch also.

[sccaGTO]

I guess I'd have to run in a Street Prepared of modified class.

[SunDown13X]

so 285s are the widest tire that would fit on a GTO? (rear)

[HaloNick]

Yup, the V710 is a fantastic tire, I have a little experience on them:
http://user.gofastlab.com/jzr/SM2vette.jpg
They really start to blur the line between a DOT-R and a slick.

I think the GTO would be fun in F-Stock on 710's, but with its heft and 245 tire size limitation I don't think it'll keep up with the Mach 1 on 275s, which I have driven a bunch also.

I know one of the guys that runs F-Stock out here seems to do pretty well with his V700s or V710s (can't remember which). He is usually right there with the stangs if not higher placed than they are. We will be going into SM class because of the s/c, so we said the hell with that and are doing a bunch of suspension stuff to it. If we have to be in that class, why not go for the gold? We will eventually buy some slicks for it (either TechRs, or V710s).

[rcpepper]

This may be even more handy...

WIDTH..........OFFSET............WIDTH OF TIRE
7.0...............+26/+65.............215/225/235
7.5...............+33/+61.............215/225/235/ 245
8.0...............+39/+55..............225/235/245
8.5..............+45/+48..............235/245/255
9.0.(MAX).........+48................245/255
REAR ONLY
8.0................+36/+65.............245/255
8.5................+42/+65...............245/255
9.0.................+48/+65...............255/265/ 275
9.5................+55/+64...............265/275/2 85

OFFSETS GREATER THAN SHOWN ABOVE WILL RUB ON REAR
FENDER LIP. (25MM FENDER LIP)

I know this is a dumb question, but a tire with an offset between the two numbers stated would work right. I'm looking at a 9.5 wide rear wheel with 56mm offset for 275/40/17 rear tires for better traction. Any answer would be appreciated.

Rob

[holler]

woah, this thread is older then jesus