I absolutely love these wheels. There is a member on here that has them, fast377, but I can't seem to get a hold of him. His wheel and tire specs are what I am looking for. 275/30/19 on the fronts and 295/30/19 on the rears.

Anybody have the numbers to make these fit to my 89 IROC? What kind of backspacing I need, if I need to use Skulte's wheel spacers, etc...

Any information would be great!

Thanks,
- Justin

 

Fast377 is running those in Corvette specs and using adapters to make them fit. He had a custom brake set up that changed the spacer specs.

He is selling that car, You never know, but might be worth a PM to see if he would sell the wheels alone to you... if they really are your favorite wheel. Me personally I would want them in the correct offset to fit without spacers.

 

Same here. I've been talking with a dealer of the Forgestar wheels that specialize in 82-02 Camaro/Firebird fitments. He's been running some calculations on how to fit them things in there. So far, doesn't look good for without spacers. I am in the process of doing a fourth gen rear end swap (donor car was a '01 Firebird T/A) in mine because my stock third gen diff just seized, so now's my excuse to finally get around to swapping it.

With that in mind, since the fourth gen rear is, what, about 2" wider on both sides?, would this change the fitment for me? As in I need to be looking at the fitment for a 98-02 Camaro/Firebird now?

 

a 275 will be at home on a 9.5" wheel, so front should be around a zero offset, or 5.25" of bs. a tad more will still fit and tuck a little better, but a brake upgrade will also change this and require some tweaking.

rear should be a 10 or 10.5 on a 3rd gen width rear, about 6-6.5" of bs respectably. Or if they have the peoper rear specs for the 4th gen rear, use those for the back. I would personally stick with a 3rd gen rear so you can get some lip on the wheels

 

I am resurrecting this old thread because i am interested in upgrading to some 18x10 ForgeStar F14 wth a 6mm offset (which equates to 5.75 inches of backspace) (According to this chart)



and then I am considering a C6Z06 BigBrakeUpgrade, hopeful that those wheels willl tuck under these brakes. I am not opposed to running some small 5mm spacers to push the wheels out toward the fenders (as I have been doing that for years), which would reduce offset, but i want to double check before a make a big $$ purchase. I am a racing application so I totally oppose spacers MORE than 10MM, i won't do it. PERIOD.

My car has GroundControl, is lowered a couple inches and I run Koni Sports all around

I'm going to run some 275 tires on front (and maybe 295 rear), do the wheel guru here have thoughts on this setup? I love BFH and have NO problem using it..

 

Super Deep Concave in 18 are now available. this is what i'm looking at

 

wheel Hub size 73.8, - they include hub rings to make it 70.3. The offset of 6 on 18x10 in the front and offset 13 in the back on 18x11..

we will see what happens.

 

you are on point with those specs i think. should look **** when on there.

did you order them yet? if so what kind of time frame and pricing are you looking at and what vendor?

 

looking like 4 weeks, i'm not sure of the price, but they are looking around $350 a wheel and weighing 21 pounds each (for a racing application that is about my MAX).

i'm bolting on my brake upgrade and my LCA upgrade in the rear so that I can fit 315 back there.

more details as they develop.

 

ok, i pulled the trigger. After talking to the wheel guys it turned out I was calculating things a bit wrong from the current spacers.

So here's the current proposal:
-----------------------------------
Front: 18x10 ForgeStar F14 Super Deep Concave with -13 offset
Bright Metallic Silver with 10MM cap to cover hubs
Including 70.3 hub ring to mate the wheel on front
Rear: 18x11 ForgeStar F14 Super Deep Concave with 9 offset
Bright Metallic Silver with flat cap to cover hubs

Getting hollow back lug nuts in 12mm x 1.5 pitch pattern so my ARP fasteners can come all the way thru the lug.

Delivery Dec 15th, $1600 from getmywheels.com

He's double checking the chrome finish, but likely going to be bright silver.

I don't expect to need any spacers, but have a couple 5MM handy just in case.

 

Idk I dont agree with the front offset, I ran about +5 mm offset with a 18x10.5 and that's about it. Those wheels will stick out. I need to run some numbers but unless you have some weird front suspension setup that will be a problem. Unless you meant +13 for the front


rear should have around +12mm to avoid a lot of metal work, or around +22 if you don't some cutting and want to keep them under the car a little

 

Ok I was running what would equate to 5.95" of bs on the front with stock brakes. The wheels your looking at have 5" of bs. That will never tuck unless you fenders are cut because racecar?? Any brake upgrade would require more backspacing to match the added hub offset

 

On the rear i was running a 18x10.5 with +17mm offset. Fit like glove with a little hammering to front of wheel well.


an 11 would need 6mm less offset, to avoid cutting, but will stick a hair outside the wheels well.

 

So on the rear that means I would need an +11MM offset instead of a +9MM, ok that's pretty close.. I can bump to 11MM, let me go look at the math on the front again.

 

Shame I didn't see this before. I have a set of 18x10.5 +27mm wheels for sale from my old build. Apex arc-8 19.5 lbs rotary forged. Drilled to 5x4.75. Rear fits with a 10mm spacer and I have custom hubs for the front so no spacers.

 

My current wheels are -7 offset and rub the inside fender on full lock. I was trying to stay with the same package.. that might be a problem.. let me double check everything. I need to look over these steering stops again with the current -7 wheels and see what I can do..

Thanks for everything. more details soon.

(oh, i put the order on hold -- i can still change it)

 

its going to stick out a little anyway if your trying to avoid sheet metal work so its probably fine, I would rather more offset and a small spacer to fit them properly.

 

big wheels will rub at lock, nature of the beast. Problem is if you go out too much they start to hit the wheel well openings so unless you cut the fenders, they wont work.

 

You can clearance the control arm and massage the fender wells a little to gain some room.

 

I missed that you using a front 10" not 10.5". Either way, you can use a bit more positive offset

 

OUTSTANDING, thanks for your advice. My though was if I was off by a little bit (larger offset that is), that I could run those 5MM spacers to push the wheel out. My suspension is Koni Sport with BMR lower control arms but everybody bolts into stock positions. Nothing too extreme, i should follow your advice.

I solved my Steering Stop problem tonight, so I will have the ability to adjust lock to lock and stay OUT Of the inner fenders now.. I am very pleased and it allows me to follow your advice on front offset.

So in conclusion, you are saying a little more offset. OK. you are running front 18x10.5 with a +5 offset (which equates to an 11 offset on a 10 inch wheel.) according to TGO calc.

So here's the current proposal VERSION #2:
-------------------------------------------------
Front: 18x10 ForgeStar F14 Super Deep Concave with +11 offset
Bright Metallic Silver with 10MM cap to cover hubs
Including 70.3 hub ring to mate the wheel on front

Rear: 18x11 ForgeStar F14 Super Deep Concave with +11 offset
Bright Metallic Silver with 10MM cap to cover hubs (same look front/rear)
(I WANT TO RUN 315 tires in the rear, do you know if a bulge of .7 inches will rub bumpstops???) - how big a tire did you fit?

Getting hollow back lug nuts from in 12mm x 1.5 pitch pattern so my ARP fasteners can come all the way thru the lug. These are the ones recommended by some friends who know racing applications
http://store.mackin-ind.com/p/32906b-black-muteki-sr48-open-end-12x1-5/shop-by-manufacturer_muteki-performance-lugs_performance-lugs-locks_12-x-1-5?pp=24

 

Best friend here is a straight edge and a tape measure, gives a good idea where things will end up. Don't forget to add for positive offset if you plan to use a brake upgrade.


so you can check my math, I ran 18x10.5 wheels with +27mm offset up front, but with custom hubs that were 1le offset (5/16" more than stock, plus .25 + another .3 for the width of the aluminum rotor jat. The wheel was a perfect fit with this setup.

 

That works out to .8625 more positive offset from the stock 10.5 brakes

 

I doubt the tires will bulge .7, but i guess that depends on the tire.

its really close to the tie rod end, to take some good measurements, I relocated the steering arms to correct the factory akerman issue

I ran 295/35/18 on all4 corners with bare minimum hammering in rear. Front had extra tall strut mounts and tall balljoints, umi control arms, koni yellows, rear was rotojoint umi control arms and a Mumford link axle locator so no side to side mivement

 

My wheels have been built, they are shipping out soon and should be here NEXT WEEK. He sent me a picture, i can't wait to get them mounted up and share my experience with all you 18 inch wheel seekers.

 

Should look good

What brake set up are you running ob the front? You still have the stock style rotor/hub?

 

I have a Wildwood 2 piston rotor which is basically identical to the stock caliper on Stock IROC spindles. The rear is PBR 1LE rear discs with Hawk pads all around

 

Did you get them yet? Can't wait to see these mounted

 

I got them, haven't put rubber to them yet and i'm going to have an issue with the front hub. let me get this sorted out and then i'll write it up with a howto and the proper specs. I think I will need a 15MM spacer (which effective changes the front offset to be -10MM ) required to clear these STUPID GM hubs. It's tough doing testing, but once I am done, you guys can copy/paste this order over and over again..

 

Got to love those hubs lol
Wheels look good get the stance right will look killer

 

I was able to make the front caps on my Boze Forged wheels work by carefully grinding material off the inside lip of the center cap.

 

NWFreerider, I know what you mean, i don't think i want to do that, but we will see. I've put this project on hold due to a death in the family. I'll get back to in a few weeks.

 

ok, first time off the lift (she's dirty as hell), but here's the first picture after the test drive.

NO RUB. 18x10,275 up front, 18x11,315 BFG Rivals-S in rear. Still have to fabricate and install the new steering stops (should be easy), and I have HUGE list before the first event of the year.

 

Oh, and I should add that i am using a 10MM spacer on the front because there was no chance in hell they wouldn't rub... it still tucked, but it required some work.. Also, i had to go with the machine shop clearancing out the center cap so the hub could stick thru. I painted it flat black to match, it's OK even if it doesn't match the rear.. it's a RACE car, so it won't be perfect.. Also, i don't race with those Lexan windows in there, they are just to keep it waterproof during travelling on a trailer to an event.

 

Those look really good on there! I just put in my order for 18x10 and 18x11 for mine yesterday. Can't wait! What type of events you gonna run this season?

 

Updated pictures after I finished up a few more of the details..

 

Oh that reminds me.. Does anyone have a passenger side turn signal for sale? HA HA

 

Considering you actually are racing with yours. Thought you might like to see this..

<iframe width="640" height="360" src="https://www.youtube.com/embed/vtYjujhW27Q?feature=player_embedded" frameborder="0" allowfullscreen></iframe>

 

Yeah thanks. I was aware of casting problem in the 2011-2012 wheels ( and earlier). The forgestar guys told me that yhey changed theor forge process (something with annealing time) and since then there have been zero failures since 2014 (maybe this is the first).

I would like to know how old those wheels are... Maybe 2013 batch?

 

Brian-What color is your car?

 

Literally every competitive wheel in existence has suffered a failure at one point or another. HRE, Forgeline, CCW, BBS....ect. Thats why wheels should be inspected regularly. The fractures for that wheel were said to look like low cycle stress induced, meaning the off road excursion most likely had a part to play(or helped) from what i have read about it.

I wouldnt be scared to run those wheels, was thinking about a set for my 4th gen. The Vorshlagg guys run those wheels and beat the hell out of them. Car looks amazing Brian.

 

2007 Corvette Atomic Orange Metallic.

Going in for wax and detail next week

 

Don't get on here much anymore, but took interest in this.

Few questions; first I was goi to ask why you have a staggered setup, but I'm assuming you are doing auto x(cam-c and lexan spoiler)

Second, why such a "small" front tire? Why not a 285-295?

These are a wheel that I'm looking at getting, but I want square. Bigger the better but I want to be able to rotate. Seeing that there isn't a 10.5 option, what do you suggest?

Thank you!

 

> Few questions; first I was goi to ask why you have a staggered setup,
> but I'm assuming you are doing auto x(cam-c and lexan spoiler)

Yes, I am doing Autocross, Track Day and other similar events, CAM-T is the class for this year and the car is very competitve in the indexed CAM classes.

>Second, why such a "small" front tire? Why not a 285-295?

275 isn't small, but haha i get what you are saying. I have heard that 295 will fit up there but the 315 rub ALL OVER the place. I could cut out some things to make it work, but it wasn't worth it for me. I found the car to be very balanced. The 315 out back just are AWESOME, so much so they have exposed other issues (like broke the transmission mount) -- i'm working all that out.

>These are a wheel that I'm looking at getting, but I want square. Bigger
> the better but I want to be able to rotate. Seeing that there isn't a 10.5
> option, what do you suggest?

I am very happy with the forgestar, I clean them between events, keep the car inside my garage with a cover over her and always inspect them for damage -- i had to have the fronts machined just a little bit to get the hubs to stick thru, but I can still put my racing slicks on there (Hoosier R7) and run on R-comps if the mood hits me and still fit under the Wilwood brakes that I have.
Overall, i'm happy with the front of the car, i'm working on a Panhard LOWERING bar so I can better put power down in the rear and likely an upgraded Torque Arm before next season.

 

http://s197forum.com/forum/showpost.php?p=2319269&postcount=23

To address the wheel breakage. I know the author personally. Not super well, but know enough to know he knows what he's talking about.


Have you looked into the decoupled ta if rules allow? I mean, there's several ways around it.

 

Also, I assumed that lowering the bar just addressed the roll center. Not sure it directly effects power-on traction? Could be mis understanding

 

It does effect power on traction when your talking corners not straight lines

 

Leveling pan hard really plants the rear a whole lot better with setup I had was perfect I had also strano adjustable rear sway but leveling panhard it just had traction I had to purposely break lose and really made car more neutral and tad looser depending on scenarios but wasn't a break away snap loose like before very predictable natural and controllable

Straight line traction is addressed with LCARB and torque arm

 

looks great man. same wheels im going with with the deep concave but in black with a center lock hub