acceptable bs on a 18x8 mustang wheel...66 cuda

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Challngd73

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I have 4 wheel disc brakes going on my 66 barracuda and need to upgrade to 15" or larger wheels. I plan on getting leaf springs moved inwards for more clearance. I see alot of threads on wheels on early a's but it seems bs is anywhere from 4.5 to 6. what is an acceptable range that will work front and back? I have lbp, and 8 3/4 out of 70 cuda in car now. And yes i did search, just havent found exactly what im looking for. found some nice ferd wheels 5x114 backspacing ranges from 5.6 to 6.2...any help is appreciated.
 
Search members for younggun2.0...he was building a '64 Valiant-moved the springs in, mini-tubbed...can't recall his intended choice of wheels, but he actually ran a 17x10 wheel out back in his other car with mini-tubs...if you actually relocate your springs in to the frame rails, you'll have tons of room.
 
...or are you only wanting to move the springs in with the offset spring hanger kit?
 
If you have four wheel disc brakes and large bolt pattern. Your car is not stock, there is no one here that can say for sure what backspacing you're going to need. Best bet is take some measurements. Probable going to be in the 5" range for backspacing if you move the rear springs in a little.

Edit
Just noticed the 70 cuda rear, don't know how much wider those are but probably a lot. Probably going to need a lot more bs than 5" on rear.
 
Ooo...good point zhandfull-I think an E body axle is almost 4" wider flange to flange than an A body...get it in the car, then as z said, take measurements and go from there.
 
txstang84 said:
Ooo...good point zhandfull-I think an E body axle is almost 4" wider flange to flange than an A body...get it in the car, then as z said, take measurements and go from there.
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so the wider the rear axle, the more backspacing is needed? excuse my ignorance, backspacing is a mystery to me and im trying to learn how it works. thanks for the responses.
 
Backspacing is the distance from the inboard side of the mounting flange to the inboard side of the rim

Offset is the measurement from the inboard side of the mounting flange to the centerline of the wheel

And if you have an E body axle, they have a 56"+ flange to flange width...A body 8 3/4" is 52" and some change, so yes you'd need a deeper backspace, but the best method is like zhandfull stated-get it put together and centered, and measure. Beyond that, the other option is to have the housing narrowed to fit what wheels you want.
 
txstang84 said:
Backspacing is the distance from the inboard side of the mounting flange to the inboard side of the rim

Offset is the measurement from the inboard side of the mounting flange to the centerline of the wheel

And if you have an E body axle, they have a 56"+ flange to flange width...A body 8 3/4" is 52" and some change, so yes you'd need a deeper backspace, but the best method is like zhandfull stated-get it put together and centered, and measure. Beyond that, the other option is to have the housing narrowed to fit what wheels you want.
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Thanks for your responses. I actually talked to my father, who i bought the car off of because he was selling it, and i grew up in that car...and he told me he put an a-body 8 3/4 in it, so I guess that means i wouldnt need as much backspace then?
 
Is it not acceptable to put a straight edge on the face of the axle where the back of the rim sits, then measure the distance to the leaf spring to find your back spacing! Of course you would do your spring relocation first, and subtract a sufficient amount for sidewall clearance, but isn't this the way its usually done?
 
cosgig said:
Is it not acceptable to put a straight edge on the face of the axle where the back of the rim sits, then measure the distance to the leaf spring to find your back spacing! Of course you would do your spring relocation first, and subtract a sufficient amount for sidewall clearance, but isn't this the way its usually done?
Click to expand...

I'm sure that method would work just fine.
 
Absolutely measure 3 times! Brake packages vary and I have no clue the room an Early A has. Typically 5" bs works fine on most A-bodies but an early A is an exception.
 
I used a wider (ford 8.8 rear and mustang "bullitt" rims with lots of backspace (4.5"?). I mocked everything together and measured ..alot! Now my 65 is 4 wheel disc, 17" 5 x 4.5 rims, 3.73:1 l.s. diff. The 8.8 is full width from an explorer.
 

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Thanks for the responses. My 4-wheel power disc brake kit is ordered and on the way. Once i get the leaf springs relocated, and brakes set, It will be measurement time. I only want to do this once so ill measure. again and again and again. Then order my rims.
 
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