Bushman66

I picked up a 04-06 GTO Spare, but this is NOT a perfect match for the bolt pattern on the C5 Corvette. The Corvette bolt pattern is 5x120.7mm vs GTO 5x120mm (close but still opens the possibility that you break or stress a wheel stud). I confirmed that it clears the brake caliper front and rear. I installed a Goodyear T145/80-17 donut spare which is a perfect match for the diameter of the stock rear tire 295/35-18 (26.1"). This spare fits perfectly in the Large Spare Tire bag available from Detroit Tuned (I ordered black to keep the trunk clean and neat). A new (used) PT Cruiser jack off ebay for $25 fits easily under the stock jacking location with an aluminum puck. An old Craftsman breaker bar with a 19mm Deep 6pt socket works on the lug nuts and the PT Cruiser jack nut.

To correct the bolt pattern misalignment, I ordered a custom wheel adapter from https://www.motorsport-tech.com. I decided on a 42mm width adapter to ensure the factory wheel studs did not protrude outside of the Adapter. This also means that I won't have to grind out the center of the GTO wheel, ensuring the wheel correctly centers on the hub. Stock stud size.

Specs for adapter as follows:

2004 CHEVROLET CORVETTE_C5_ZO6
Your Bolt Pattern: 5x120.7mm
Your Hub Diameter: 70.3mm
Type: One Piece Adapter
Hub Centric to Car & Wheel Centric to Wheel
Thickness: 42mm
Stud Size: 12x1.5
Center Bore: 69.5mm
Diameter: 5 by 120 (4.72 inches)
Price each: 75.00
Total Quantity: 1

All of this seems like a lot of work and money, but I've had enough flats here in Phoenix that couldn't be fixed with Slime and a compressor, that I have ZERO desire to wait outside for Roadside Assistance (especially when it's 112 degrees out!), not to mention road trips across the desert or up north, many times out of cell coverage. Hope this info helps someone looking to put a spare kit together.

Vetteman Jack

JR-01

Have you tried getting that jack under it with a totally flat tire?

Bushman66

Yep! At 0 pressure (but still sitting on the sidewall somewhat), I have a solid inch to the puck. Completely on the rim, it would be close, but in that case I'd just leave the puck off and jack directly on the pad. The PT cruiser jack has a very small platform so this could not create any issues.

Note: my Z is at stock ride height. With a lowered car, you'd almost certainly need a mini ramp or 2x6 to drive up on first.

Sydwayz

And how are you securing all of these heavy projectiles in the event of an accident?