wheel adapter question 84 c4
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8th Gear
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wheel adapter question 84 c4
I've looked on here for some info on putting wheels on my 84 c4 but no luck finding what i'm looking for.So hopefully someone can lead me in the right direction?I bought a new set of wheels they are 17"x9.5" with a 54 mm offset and 275/40/17 tires can anyone give me a starting point on what size adapters to use.Stock wheels have a 5.25" backspacing,new wheels have a 7.75" backspacing so i'm figuring about 1.5" +/- or is there anyone who knows what the max backspacing is?any input would be greatly appreciated thanks !!!My stock wheels are 16"x8.5" with 38mm offset!There aftermarket ,i just measured my stock wheels and they are 5.25" from mounting flat to inside lip of wheel!Thats giving me a 2.125" difference in backspacing,don't think 3/4" spacers will get me enough clearence?
Last edited by thewrenchhead; Mar 24, 2009 at 09:16 PM.
Team Owner
Joined: Sep 2003
Posts: 25,389
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Early C4's with 9.5" wheels were done with 38mm offsets so simple math would indicate 16mm spacers to keep similar inside clearance to suspension components. I believe you'll find the most frequently used spacer/adapter used by early C4 owners is a 3/4" (19+mm). The 3/4" is a very common mass production product and is less expensive than the "specialty" product.
It is also an "accepted" rule that depending on the construction of the "back-side" of the wheel mounting surface there are limitations of the spacer/adapter choice. I won't comment directly, research and make your own decision! My comment is directed only toward a "dimension" for "near stock" wheel "placement"!!
It is also an "accepted" rule that depending on the construction of the "back-side" of the wheel mounting surface there are limitations of the spacer/adapter choice. I won't comment directly, research and make your own decision! My comment is directed only toward a "dimension" for "near stock" wheel "placement"!!
Le Mans Master
Joined: Aug 2000
Posts: 8,838
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From: Australia
The late model 17" rims are 7.4" BS / 54mm offset and need a 3/4 spacer to sit correct
Are the wheels factory late C4 rims or aftermarket?
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Early C4's with 9.5" wheels were done with 38mm offsets so simple math would indicate 16mm spacers to keep similar inside clearance to suspension components. I believe you'll find the most frequently used spacer/adapter used by early C4 owners is a 3/4" (19+mm). The 3/4" is a very common mass production product and is less expensive than the "specialty" product.
It is also an "accepted" rule that depending on the construction of the "back-side" of the wheel mounting surface there are limitations of the spacer/adapter choice. I won't comment directly, research and make your own decision! My comment is directed only toward a "dimension" for "near stock" wheel "placement"!!
It is also an "accepted" rule that depending on the construction of the "back-side" of the wheel mounting surface there are limitations of the spacer/adapter choice. I won't comment directly, research and make your own decision! My comment is directed only toward a "dimension" for "near stock" wheel "placement"!!
"Missed by that much" as a certain secret agentwould say
Team Owner
Joined: Sep 2003
Posts: 25,389
Likes: 2,741
I believe you could be just missing the correct "dimensioning" of the back-spacing and I used 9.5" only wheels for "wheel placement". I mentioned nothing regarding the factory offset of later C4 wheels. It is not 54mm it's 56mm. What's 2mm? Nothing regarding yours but it isn't a fact!
An '84 with an 8.5" 16" wheel is something near 6.0+ for back-spacing and is only a 32mm offset(I'm quite sure)!
It's of little use to debate the specifics but if you use 9.5 width and the "advertised" offset is 54mm the math is correct in mine and the statement by "both rodj & myself" that the "more" popular spacer/adapter is 3/4".
Correct dimensioning for back-spacing is wheel mounting flange to "extreme edge" of inside edge of wheel!
An '84 with an 8.5" 16" wheel is something near 6.0+ for back-spacing and is only a 32mm offset(I'm quite sure)!
It's of little use to debate the specifics but if you use 9.5 width and the "advertised" offset is 54mm the math is correct in mine and the statement by "both rodj & myself" that the "more" popular spacer/adapter is 3/4".
Correct dimensioning for back-spacing is wheel mounting flange to "extreme edge" of inside edge of wheel!
Last edited by WVZR-1; Mar 24, 2009 at 09:44 PM.
