Wheel spacers - Fourth Generation Pontiac Firebird (1993 - 2002) - Firebird Nation

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Wheel spacers


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4 replies to this topic

#1 Narfbrain

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Posted A week ago

Sorry boys don't know how to search on here just got a set of c5 thin spoke rims just wondering if anyone knows what size wheel spacers i need? Thanks

#2 Injuneer

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Posted A week ago

You need to provide the width and offset of the wheels to determine the required spacers (if any).  The C5 came with various stock front and rear wheel sizes.  Are they OEM or aftermarket/reproduction?


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381ci all-forged stroker (Callies Stealth, Oliver billet rods, BME 2618-T61 nitrous pistons) - 10.8:1 - CNC LT4 heads/intake - Comp Cams solid roller - MoTeC M48 Pro engine management - 8 LS1 coils - 58mm TB - 74#/HR injectors - 300-shot dry nitrous - TH400 - Gear Vendors 0.78:1 O/D - Strange 12-bolt - 4.11 Pro-Street gears - AS&M headers - true duals - Corbeau seat - AutoMeter gauges - roll bar - Spohn suspension - QA1 shocks - a few other odds 'n ends. 800HP / 800lb-ft at the flywheel, on a 300-shot. 11.5 @ 117 MPH straight motor
 
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#3 Narfbrain

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Posted A week ago

They are OEM thin spoke corvette wheels from a 1999 Vette....I have heard people say 1 1/2 but that seems like much too much to me also heard 1" I just want the right spacers the first time before I prefer them in

#4 Injuneer

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Posted A week ago

The 1.25" spacers are required for the C6 wheels, specifically the 19"x10" rear wheels, with a huge +79mm offset (8.6" backspace).  Without the spacers, the wheels/tires are hitting the inner fenders, the jounce bumper, and the lower control arms,  You can't physically go over 8.00" backspace on a 4th Gen F-Body.  Here's a thread on another site the confirms this.

 

https://www.camaroz2...4th-gen-528858/

 

 

The data I can find on the C5 wheels indicates:

 

1997-1999 Base Model ("wide" spoke):

- Front 17x8.5 56mm

- Rear 18x9.5 61mm

 

2000-2004 Base Model ("thin" spoke)

- Front 17x8.5 58mm

- Rear 18x9.5 65mm

 

2001-2004 Z06:

- Front 17x9.5 54mm

- Rear 18x10.5 58mm

 

I'll assume you are asking about the 2000-2004 wheels.

 

There is no physical need for a spacer in the front.  You will end up with a 2.5" frontspace and a 7.0" backspace.  Aesthetically, you might want to move the wheel/tire out about 1/2".

 

The rear MAY require a spacer, but not because there is a major physical interference with the inner fenders and suspension.  You will end up with a 2.7" frontspace and a 7.8" backspace.  That puts the wheel/tire deep in the wheel well.  It may possibly catch the projecting edge of the jounce bumper when you jack the car.  You may need to hammer the inner fenders lightly.  Aesthetically it would help to move the wheel outwards about 1", yielding the equivalent of a 3.7" frontspace and a 6.8" backspace.

 

Technically, these are adapters.... the adapter bolts to the factory lugs and has an additional set f lugs to mount the wheel.

 

All these calculations are based on 1) the accuracy of the data I found on the web, 2) an assumption regarding the width of the two flanges that retain the tire beads on the wheel (0.50" each); and 3) the particular wheel I selected, which may or may not be the 1999 wheel you are talking about.  There was a magnesium wheel option in 1999, with thin spokes, but those are really rare, based on a $3,000 additional cost.

 

I have 11" wide wheels, 50mm offset, with 0.46" wide retainer flanges in the back, with a 7.93" backspace.  I had to hammer the inner fenders, recenter the body side-to-side over the axle assembly, and cut the projecting edge of the jounce bumper.  My wheels have a 4.00" frontspace which puts the outer edge of the tire directly under the outer edge of the fender, when looking straight down from above.

 

My suggestion would be to get the wheels, test fit them, and determine how much you would like to move the wheel/tire outward toward the outer edge of the fender, and buy an adapter with that width. 



#5 Narfbrain

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Posted A week ago

Fair enough....ya they are just catching on the inside bounce bumper so I was thinking 1"




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