Old Europe has this: http://www.fiero.com/forum/Forum1/HTML/058236.html
But of course we can do better.
What's the goal of putting serious wheels on your car?
- To put as much rubber on the ground as possible, consistent with good contact patch loading.
- To produce correct steering geometry relative to the front contact patches
For 8" rear wheels, a 6.4" front would be ideal
8.5" rear -> 6.8" front
9" rear -> 7.2" front
9.5" rear -> 7.6" front
10" rear -> 8" front
2. Getting the offset right on the front wheels to produce good steering geometry is vitally important for a car with manual steering. Because of the high "offset" of the '84-'87 Fiero front knuckles (distance from wheel mounting surface to kingpin axis), the front suspension requires very high offset wheels in order to keep the "Dave point" of the front suspension in the correct location relative to the contact patch.
The effect of high offset wheels can be easily demonstrated on an early Fiero. The Mule is an '87 GT. It's currently fitted with Chrysler LeBaron 16x6 wheels on the front. These wheels are very high offset, and have reduced steering effort on the '87 to about the same as my Formula, if not a bit lighter. I should be able to measure the offset of these wheels next weekend.
Since the rear end of the Fiero limits the overall wheel and tire width, the correct width and offset for the rear is critical. This will vary by the diameter of the *WHEEL*.
The front of the Fiero has plenty of room for wheel and tire width compared to what it needs to keep the correct relationship with the rear width. The offset to keep the steering geometry correct is the critical aspect of a front wheel/tire fitment. This will vary by the diameter of the *TIRE*.
ALIGNMENT specs are also important, as the relationship of the tire to the strut body is affected by the rear camber adjustment, for example.
1984-1987 REAR: by wheel diameter and offset
16 inch wheels
16x8-25 (5x115) from early '90s Grand Prix, run with -1.5 degrees of camber. I have tested these on my car with the A-body hub carrier swap. The inner edge is 1/4" from the knuckle and the outer edge is about as far out as I'd want to see it with stock bodywork. I'll try to get pics this weekend.
17 inch wheels
17x9-45 according to WCF: http://www.westcoastfiero.com/faq/faq.html
Comparing to the 16" combo above, a 17x9-38 should also work.
I have not tested either of these; WCF did not specify 84-87 or 88 car or what alignment specs are used.
18 inch wheels
Going by the info above, 18x9-38 and 18x9-45 should also work.
Enkei PF01's for example are available 18x9-35 (5x114.3) and 18x9.5-45 (5x114.3) ( http://www.enkei.com/pf01.html# and http://www.enkei.com/size_chart/PF01.pdf )
C5 Corvette rear wheels at 18x9.5-65 fit with 1" to 1 1/8" (25.4mm - ~28mm) adapter. That means that 18x9.5-40 should fit.
1984-1987 FRONT: by tire diameter and offset
16 inch wheels
16x6-40 (5x100) from a 89-91 Chrysler LeBaron. I will measure the offset on a spare this weekend. These wheels have very high offset and work well with the '84-'87 steering knuckle.
IIRC, the pilot bore had to be enlarged to work with the Fiero hub.
16x7-?? (5x115) from mid '90's Bonneville. These are identical to the 16x8 Grand Prix wheels above except for the width and lip. I may be able to measure the offset on some spares this weekend.
17 inch wheels
17x8-45 according to WCF: http://www.westcoastfiero.com/faq/faq.html
I have not tested this; WCF did not specify 84-87 or 88 car or what alignment specs are used.
18 inch wheels
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