BackSpace question with a B-Body 8 ¾” in an A-Body
#1714026
12/22/14 03:12 PM
12/22/14 03:12 PM
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Joined: Jan 2003
Posts: 751 Saint Peters, MO
Brian
OP
super stock
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OP
super stock
Joined: Jan 2003
Posts: 751
Saint Peters, MO
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Here’s the deal, I want to go to a 17” x 8” wheel probably running a 235/50-17 which are 26.3” tall all around on my 1971 Duster. This size tire allows me to run modern maximum performance summer tires while still retaining enough sidewall height to look correct. Ideally I would like to run the same size wheel with the same offset (BackSpace) all around as well. I may consider larger rear tires for the track if traction is a big problem.
Since I’m also upgrading the front suspension to 73-76 spindles with 11 ¾” discs with Gen I Viper calipers that will push the front wheels out requiring a wheel with a lot of positive BackSpace; it seems that the narrow A-Body 8 ¾” rear is not wide enough and will require a much deeper negative BackSpace to push the wheels back out into the quarter Panels. If that’s the case, I can’t rotate the tires front to rear and would have to carry a generic spare tire like a 205/70-15 on a steel wheel assuming that would clear my front brakes.
Question: Would a 8 ¾” B-Body rear that is 3” wider overall push the rear wheels back out into the quarter panel enough so I can safely run the same positive BackSpace wheels front and rear? What BackSpace am I looking for (5.5” I’m guessing)?
Help!
1971 6.1 Gen III Hemi Duster
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Re: BackSpace question with a B-Body 8 ¾” in an A-Body
[Re: AndyF]
#1714028
12/22/14 04:02 PM
12/22/14 04:02 PM
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Joined: May 2005
Posts: 723 Houston Tx
Uhcoog1
super stock
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super stock
Joined: May 2005
Posts: 723
Houston Tx
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Brian-
Yes, you *should* be able to run the same wheels square on the car with a 68-70 B body rear. You may need slightly more width.
The front ride height also has a significant impact on the best backspacing in the front.
When doing your math, keep in mind the A body swapped to a 5x4.5" is slightly wider than the 5x4" original.
I've got a spare gt500 wheel (18x9.5, +45mm offset = 7.2" backspacing) and an old continental scrub you can mount. You can play with it and spacers to find your ideal tire position in the front wheel well and then set up the rear axle to fit the same wheel. Come borrow it whenever you like.
-'02 Dodge Viper Ex-World Challenge racecar -'73 Duster, 6.1 based 392 hilborn hemi, tko600, full floater rear 9", Hellwig custom bars, viper brakes, built for road course
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Re: BackSpace question with a B-Body 8 ¾” in an A-Body
[Re: Uhcoog1]
#1714029
12/22/14 10:18 PM
12/22/14 10:18 PM
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Joined: Jan 2003
Posts: 751 Saint Peters, MO
Brian
OP
super stock
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OP
super stock
Joined: Jan 2003
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Saint Peters, MO
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Wade, Trade you the wheel and tire for a 5.7 bare block and an engine stand! Here is what I'm now considering: 17"x 8", 25mm backspacing (5.5") I hate to go to an aftermarket wheel, but these look good to me and are cost effective. http://www.customwheelsexpress.com/custo...VGRsaAnGl8P8HAQLooking at these tires: Potenza S-04 Pole Position $128 at the Tirerack.
1971 6.1 Gen III Hemi Duster
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Re: BackSpace question with a B-Body 8 ¾” in an A-Body
[Re: Brian]
#1714030
12/22/14 10:23 PM
12/22/14 10:23 PM
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Joined: Sep 2004
Posts: 1,828 houston texas
gremlinsteve
top fuel
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top fuel
Joined: Sep 2004
Posts: 1,828
houston texas
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I had the tire measuremet tool also. Bolts to the hub and allows you to determine if what you want will fit. Percy's made it.
U Ian borrow it too
if You Like Gremlinsteve. Gremlinsteve Likes You.
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Re: BackSpace question with a B-Body 8 ¾” in an A-Body
[Re: AndyF]
#1714032
12/23/14 03:05 AM
12/23/14 03:05 AM
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Joined: Jan 2003
Posts: 27,468 So Cal
autoxcuda
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 27,468
So Cal
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Quote:
Look at the articles in the tech archives on Tim's red Valiant. We sat his car up to use Mustang 17x8 (or 17x9) rims on four corners. It had a B-body rear end under it and special hubs up front.
Did you use a 65-67 B-body rear or 68-70 B-body rear?
People should realize carefully picking between those two are different widths and can help fitment with whatever your particular rims' backspacing.
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Re: BackSpace question with a B-Body 8 ¾” in an A-Body
[Re: pauly v.100]
#1714040
12/26/14 12:46 AM
12/26/14 12:46 AM
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Joined: Jan 2003
Posts: 751 Saint Peters, MO
Brian
OP
super stock
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OP
super stock
Joined: Jan 2003
Posts: 751
Saint Peters, MO
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I'm waiting to hear about '67 B-Body 8 3/4", sounds like it would be perfect, thanks!
1971 6.1 Gen III Hemi Duster
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Re: BackSpace question with a B-Body 8 ¾” in an A-Body
[Re: Brian]
#1714042
12/26/14 01:28 AM
12/26/14 01:28 AM
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Joined: Feb 2011
Posts: 4,302 Nebraska
72Swinger
master
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master
Joined: Feb 2011
Posts: 4,302
Nebraska
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I have a 67 B body rear. The track is still narrower than the front but with disc's in the rear it would be about right or close. I think my rear wheels are about 1/2" deeper than the fronts outer lips.
Mopar to the bone!!!
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