Back spacing on B body rear end in 73 Duster
- Thread starter 22Duster
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I'm running the B rear in my 74 Dart Sport. I have 10" wheels with 5 1/2" BS.
The tires do not stick out beyond the quarter.
The tires do not stick out beyond the quarter.
6" of backspace should center the wheel in your wheelhouse. This assumes, no relocation or mini tub.
Figure out from there how much less you can run to keep the tire out of the outer lip.
Figure out from there how much less you can run to keep the tire out of the outer lip.
Good post, I just did this 2 days ago, haven't installed wheels yet, still waiting on parts to arrive and to set up the diff. I put in a 66 B body that is supposed to be the narrower of the B body rears. :blob:
Well its stock spring location and and I did move the perches in to stock width. I guess what I would really like to know is I want to run the ralley wheels but they don't come in more than 41/2 backspaceing so I looked into having my 14's changed to 15 X 8 and price wise it is 130 a rim and they can move the backspaceing but I did find some 15 X 8 for 200 a pair but still only 4.5 it's just I have heard it both ways to move out and not to move out.
5/16" per inch on each side. So figure a ~5.75 BS to get the wheel centered.
Have a set built. Summit will have it done with one of their vendors. Might cost a couple bucks more than the listed pricing. I'd call summit customer service.
Thanks, I bought a set of centerlines off of a friend and member here weeks ago. They are 15x7's with whatever the standard backspace is 3/38's or something like that. Look ok with the stock 8/14 rear but since I decided to change out the rear diff, I may go with something more from what I've found that this diff will push the tire out a little further towards the quarter so that would give me more room towards the spring. Once the diff is done and I can install it and the axles then I will know what my options are. 5.75 would be great to get more tire under the car.
Specialty Wheel has 15" Rallyes 5x4 1/2 BP with a 5" BS.
http://www.specialtywheel.com/product-showcase/mopar/chrysler-rallye-large-bolt-pattern.html
IF you want more they can custom build a set I believe.
pauly v.100
Well-Known Member
I use 6.25 backspace with no issues on the tire/spring clearance. Crackedback got it right, with an 8" wheel 5.75 backspace will be close to centered in your wheel well.
Crackedback is right on!
I use a later 68-70 B body rear with 1/2" relocated springs (perches 42" c-c) on my '74 Duster. I have 18x10's with 7" backspace on it with 295/35/18's. Wheel is centered, pretty much no room anywhere.
My combo would have the same centerline as an 8" wide wheel with a 6" backspace, so with the shorter rear housing 5.75" should be pretty close.
As far as the tire, with the stock spring location 275 is about as wide as you can safely go unless you jack up the rear ride height to clear the quarter. I tried a set of 275's on my Duster before I swapped the rear end out and did the offset, they were clear but not by a ton.
I use a later 68-70 B body rear with 1/2" relocated springs (perches 42" c-c) on my '74 Duster. I have 18x10's with 7" backspace on it with 295/35/18's. Wheel is centered, pretty much no room anywhere.
My combo would have the same centerline as an 8" wide wheel with a 6" backspace, so with the shorter rear housing 5.75" should be pretty close.
As far as the tire, with the stock spring location 275 is about as wide as you can safely go unless you jack up the rear ride height to clear the quarter. I tried a set of 275's on my Duster before I swapped the rear end out and did the offset, they were clear but not by a ton.
Duster looks good, from the research I was able to find here and other sites the later b body rears are little wider than the earlier one's so it would push the wheel out further allowing more backspace than the earlier b body rear. Mine I just put in was a 66 or 67. Don't know on how the wheels will look yet as I don't have the diff set up yet to install the axles, but will use that formula on the 8 inch wheel with the 5.75 backspace if the one's I have don't look right.
pauly v.100
Well-Known Member
My setup uses a 69 runner rear end so thats what I base everything to. as I understand it however, different year b-body rears can have different widths. at least thats what i heard. -pauly
'68-'70 B body rears are 54 15/16", '65-'67 should be 54 1/4". So like Crackedback said, about 5/16" shorter per side for the '65-'67 B rears.
Based on squeezing every inch of space out of my Duster's stock wheel tubs, I would say you're going to need to be between 5.5" and 5.75" of backspace on an 8" wide rim. And a little "too much" can be dealt with using a small spacer, so I'd be inclined to go with 5.75" unless your measurements show much different.
Based on squeezing every inch of space out of my Duster's stock wheel tubs, I would say you're going to need to be between 5.5" and 5.75" of backspace on an 8" wide rim. And a little "too much" can be dealt with using a small spacer, so I'd be inclined to go with 5.75" unless your measurements show much different.
Mopar92
Well-Known Member
I realize I’m digging up an oldie here... but I’m about to do the same.
73 Duster.
My B body rear measures 55” or so.... end of housing. Not the axle Flange but the housing.
My perches are 44” give or take an 1/8”. I wonder if stock 7” police wheels will fit inside the stock houses with this setup.
73 Duster.
My B body rear measures 55” or so.... end of housing. Not the axle Flange but the housing.
My perches are 44” give or take an 1/8”. I wonder if stock 7” police wheels will fit inside the stock houses with this setup.
duster2
Well-Known Member
I have a pair of 15 X 7 Magnum 500 wheels with a 5 1/8 backspace for sale , also have a pair of 15 X 6 Magnums to match. Let me know if they will help.
Frank
Frank
Mopar92
Well-Known Member
I’m all set on wheels thanks.
So based on your housing measurements that’s a 68-70 B body 8 3/4. The stock police wheels are 15x7 with a 4.25” backspace, and you can run those with that B body rear axle. They will limit your tire size pretty significantly though, I ran that exact combination on my ‘74 Duster, and with 225/60/15’s I was out of room to the quarter. They fit, but you can’t run a wider tire than that with original cop wheels.
And regardless, you will need to move the spring perches to 43” center to center
Mopar92
Well-Known Member
Thanks. I have perches. I could always have the wheels cut and offset later. Honestly it’s going to be a fair weather daily driver. I don’t want 275’s or anything meaty on it. As long as it fits initially I can always change wheels another rainy day I guess. Thanks for that input.
Mopar92
Well-Known Member
Forgot I even replied to this. Looks like with the 68-70 B body axle, I need 8” wheels, 5.75” backspace to run a 255 or so tire on it with stock spring location? I’m cutting and welding on new perches soon. Thanks.
Yup, that should work pretty well
Mopar92
Well-Known Member
I’d think with the 255 I’d have some safe zone on both sides too.
It’ll depend on the body tolerances on your car, your ride height, etc. But yes, you should have a little wiggle room if those work in your favor.
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