In the quest to go faster many of us have already fit bigger rubber under our cars.
Yet I see many times that some of the new folks still need the info necessary to make them fit........So here it is.
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General offset info.

The offset that most are using is a 50mm offset. This of course being the Corvette Grand Sport offset rear wheel, and the replicas of. This is close to ideal for the Camaro and Firebird.

36mm Is the Corvette ZR1 offset rear wheel, and replicas of. It has a little less offset and spaces the wheel out further. The 36mm offset is probably the best choice for the Firebird body, which is wider in the rear, and also apparently in the front. This offset eliminates the need for any spacers.

See the car specific section for more info.
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First off the front hubs, and rear axles (possibly) need to be pulled off/out to change the wheel studs.
Longer studs will enable you to use spacers where necessary, and are a nice strength upgrade.

ARP sells the necessary studs specifically for the Camaro/Firebird/Corvette They are both longer, and threaded all the way to the end. 12mmx1.5".59 knurl. They are a heat treated 8740 chromemoly, tensile strength 190,000 psi.

The front hub's studs are easiest to change in a small press. It doesn't take a lot of pressure, and once the hubs are out, the whole process takes 5 minutes.

The rear axles on non traction controlled cars are best to just be pulled. Just be carefull with the bolt holding in the crosspin on your T2R, it's easy to bugger up the head. Beyond that, same deal, 5 minutes.

I'll add TCS info later....
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Body mods...Rear

It's required that the rear fender lip be rolled. This will prevent any damage to expensive race tires. There are many ways of accomplishing this, including carefull work with a BIG hammer.

There will also be a place in the rear fender area that needs to be beat in with a BIG hammer. I've heard it's possible to damage the rear seat post area inside the car so be sure the seat is UP before using the big hammer.
Once the wheel/tire combo is in place you will see the spot. You'll also probably need to "re-adjust" the fender after the first few runs, so be sure to bring a hammer with you to the first event.

Body mods front.......

The front will require very little work. Directly above the tire, in the 12o'clock position is the only place needing attention. A strip of plastic liner needs to be removed, sized 2"x8". This will right next to the outer fender lip. Directly above this area (it will be visable once the plastic liner is removed) is a thin metal lip. Once the plastic wears through, this lip can cut your front tires. A small hammer is used to beat the lip outwards and flatten it out. Easy. Done.

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Suspension mods......

#1 Suspension mod will be a rod end panhard rod. The rods with poly at one end or both, allow to much flexing. This will do TWO things. One is prevent ANY deflection in the PHR, and two, is allow perfect placement of the rear axle.

The rear axle needs to centered in the car perfectly. Sort of. GM build quality leaves a bit to be desired so I think it's best to adjust the axle to prevent rubbing. Whatever that means on YOUR car. For instance my car needed to be adjusted to prevent rubbing on the outer fender lip. So I adjusted accordingly. Other cars have more room here, and less on the inside.

Also keep in mind that a stock car will encounter more rubbing than a "setup" car. Larger front and rear swaybars, stiffer springs, and stiffer bushings will contribute to less tire rub.
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Car specific, and other important tidbits......

Camaro. A 50mm offset wheel is probably the best compromise. This wheel offset requires a spacer up front, to move the wheel lip away from the bump on the spindle. In back the 50mm offset can be used without a spacer. Or a VERY thin one (3rd Gen IROC 1/8" spacer)

There isn't a way to get the ideal offset for the Camaro. Custom wheels are an option and can eliminate the use of spacers. However, to have the ideal offset front and back, requires the use of different front and rear offsets and prevents rotating.


Firebird. The ideal offset here is the 36mm. It fits on front and back and requires NO spacers. This could reduce costs in parts and labor as you could continue to use the stock wheel studs. This wheel offset also prevents rubbing on the inside, while there is room on the outside. AND allows rotating.


Different wheels can, and will, have more room. Even in the same size/offset. For instance the cast wheels available have a thick squared off flange at the wheel lip area. It's a necessary design feature for integrity purposes. However, a custom built forged wheel will have more room in this area, and won't require as large a spacer.

Another important note is ACTUAL tire width. If you fit your car to a set of Kumho Ecsta V700's you will have less room if you switch to Kumho V710's, for example.....Break out the hammer again....

Another subject I had't touched on is the "bumpstop issue" in the rear of the car. It isn't one IMO, and I use stock bumpstops in the stock location. The rear wheels won't go into "full droop" because the bumpstop catches the inner wheel lip. Some have trimmed their stops or removed them. All of which alters the function. I beleive this isn't a big deal simply because the only reason for letting the wheels hang is to remove the springs. In which case the wheels would probably come off anyhow. The choice is yours. The bumpstop will hit the wheel.

I think that covers most everything. I will lock the thread and sticky it
for future reference. If you have other info to add please PM me, and I'll add it.