Wheel Gurus - Is my offset calculation correct ???
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Racer
Joined: Apr 2006
Posts: 346
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From: New York NY
Wheel Gurus - Is my offset calculation correct ???
I am trying to fit 2002 Z06 rims on an 87 c4 that currently has stock 8.5s
c4 faq says the offsets are:
Z06 Front rims are 17 x 9.5" about 10.5 overall width
backspace = 7 3/8"
Formula Backspace - (overall width / 2 ) = offset
7 3/8 - (10.5 / 2) = offset
7 3/8 - 5 2/8 = 2 1/8
2 1/8 = approx 54 mm offset
so to match my 87 - if 8.5's have a 36mm offset, then I need to calculate the diff
54 - 36 = 18mm
18 mm just under 3/4"
and that means I need to buy a 3/4" spacer for the Front to fit the wheelwell and fender properly.
Z06 Rear rims are 18 x 10.5" about 11.5 overall width
backspace = 8"
Formula Backspace - (overall width / 2 ) = offset
8" - (11.5" / 2) = offset
8" - 5 3/4" = 2 1/4"
2 1/4 = approx 57.15 mm offset
57 - 36 = 21mm
21 mm = 0.827 or 13/16" (0.8125") 1//16 shy of 3/4"
and that means I need to buy a 3/4" spacer for the Rear to fit the wheelwell and fender properly.
Am I right here ???? 3/4" spacers all around for the Z06 rims to fit an 87 C4 properly.
... and what should I be spending for them I have seen prices from $10 to $250
Thanks
c4 faq says the offsets are:
84-87 38mm for the 9.5" rim, 36mm (I believe) for the 8.5" rim....
backspace = 7 3/8"
Formula Backspace - (overall width / 2 ) = offset
7 3/8 - (10.5 / 2) = offset
7 3/8 - 5 2/8 = 2 1/8
2 1/8 = approx 54 mm offset
so to match my 87 - if 8.5's have a 36mm offset, then I need to calculate the diff
54 - 36 = 18mm
18 mm just under 3/4"
and that means I need to buy a 3/4" spacer for the Front to fit the wheelwell and fender properly.
Z06 Rear rims are 18 x 10.5" about 11.5 overall width
backspace = 8"
Formula Backspace - (overall width / 2 ) = offset
8" - (11.5" / 2) = offset
8" - 5 3/4" = 2 1/4"
2 1/4 = approx 57.15 mm offset
57 - 36 = 21mm
21 mm = 0.827 or 13/16" (0.8125") 1//16 shy of 3/4"
and that means I need to buy a 3/4" spacer for the Rear to fit the wheelwell and fender properly.
Am I right here ???? 3/4" spacers all around for the Z06 rims to fit an 87 C4 properly.
... and what should I be spending for them I have seen prices from $10 to $250
Thanks
