Wheel Size Question.

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Jim910

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Hello,
I recently purchased a 1967 Barracuda Formula S (273) and I am looking to purchase some 15 x 7 SBP Cragers. Summit Racing has them and I want to make sure that I am getting the correct size for fitment. The ones I am looking at have a backspace of 4.125" and an offset of +3 mm. Could someone let me know if these are the correct size. Also, I would appreciate some suggestions as to what size tire to get. I live North of NYC and I plan to set up the suspension to take advantage of the beautiful winding country roads and switchbacks up here. I really want to emphasize the "S". Before I start tweaking the suspension I want to get some proper performance tires on her. Appreciate any help. Thanks.
Cuda 2.jpg
 
17" -18". Tire selection is much greater.
I totally get it. I first considered 17" but I haven't seen anything decent looking with a 5 x 4 bolt pattern. I may have overstated my intent when I said "emphasizing the "S" ". At this point in time I'm not looking to make any significant modifications. I really like the look of the Cragers, especially against the blue paint. Reminds me of my younger days. If I could find them, or something similar, in a larger diameter wheel l would definitely consider them. For now I'm not ready to go for the steps necessary to convert the bolt pattern. Maybe down the road the bug will bite but for now I'm just looking to get a good looking wheel with a decent tire over my Kelsey Hayes disc brakes with a 5 x 4 bolt pattern. 15" wheels have a much larger selection of tires that 14". I'm new to A Bodies. Up till now I've been a modem Mopar guy. So for now I want to make sure that the wheels I'm looking at have the correct measurements. Can you help me with that? Thanks.
 
A 15 x 7 rim should fit fine as long as you maintain the same offset as the factory rims. Your "S" should have 14 x 5.5" rims. I'm not sure what the factory backspace was, but I would guess something like 3.25. An easy way to compare backspace is to take half the difference. 7 minus 5.5 = 1.5 / 2 = .75; 4.125 minus .75 = 3.375. If 3.375 matches the stock backspace, the rims will center the same way in the wheel wells, so if your tire diameter is the same or less than stock, they should fit OK (plenty of width in the back). On a 7" wide rim, a quarter-inch either way is probably close enough. The tight area is at the front lower edge of the front wheel well — when the steering wheel is turned and the suspension is compressed, this is where it will rub. Check the clearance here with your current tire, and extrapolate to a wider tire. Put the jack under the lower arm and raise the wheel up with and turn it all the way left and right and note where it comes closest. Anecdotally, I have heard that a 225/60-15 is right at the edge — might rub and might not. You don't have the stainless wheel well trim so that gives you a little extra room. Like your car, BTW.
 
My 69 Barracuda takes a 4.5" backspace with 0 offset on a stock 8 3/4 SBP rear and stock suspension. You safely have 5.5 inches from the front of the drum to the leaf spring and an almost identical distance from the front of the drum to the wheel well lip. So your 4 1/8" (4.125) backspace with a 3 mm+ offset would equal 4 1/4" total backspace, or very close. You're definitely safe with those rims. Now, don't sell yourself short on rims due to the 5x4 bolt pattern. If you check American Racing Wheels (for example) they offer certain wheels as "custom". Those wheels can be done with the SBP and you set your backspacing and offset. AND.....you get a 17" or larger wheel which offers a lot more tire size options. I am waiting to get an order in but Covid has slowed everything down.
 
A 15 x 7 rim should fit fine as long as you maintain the same offset as the factory rims. Your "S" should have 14 x 5.5" rims. I'm not sure what the factory backspace was, but I would guess something like 3.25. An easy way to compare backspace is to take half the difference. 7 minus 5.5 = 1.5 / 2 = .75; 4.125 minus .75 = 3.375. If 3.375 matches the stock backspace, the rims will center the same way in the wheel wells, so if your tire diameter is the same or less than stock, they should fit OK (plenty of width in the back). On a 7" wide rim, a quarter-inch either way is probably close enough. The tight area is at the front lower edge of the front wheel well — when the steering wheel is turned and the suspension is compressed, this is where it will rub. Check the clearance here with your current tire, and extrapolate to a wider tire. Put the jack under the lower arm and raise the wheel up with and turn it all the way left and right and note where it comes closest. Anecdotally, I have heard that a 225/60-15 is right at the edge — might rub and might not. You don't have the stainless wheel well trim so that gives you a little extra room. Like your car, BTW.
Yes to that and the 225/60R15 may well rub because the wheel you are looking at pushes everything out 1/4". A 225/60R15 will fit the rear fine. You can likely go to a 235/60R15 on the rear without issue.
 
A 15 x 7 rim should fit fine as long as you maintain the same offset as the factory rims. Your "S" should have 14 x 5.5" rims. I'm not sure what the factory backspace was, but I would guess something like 3.25. An easy way to compare backspace is to take half the difference. 7 minus 5.5 = 1.5 / 2 = .75; 4.125 minus .75 = 3.375. If 3.375 matches the stock backspace, the rims will center the same way in the wheel wells, so if your tire diameter is the same or less than stock, they should fit OK (plenty of width in the back). On a 7" wide rim, a quarter-inch either way is probably close enough. The tight area is at the front lower edge of the front wheel well — when the steering wheel is turned and the suspension is compressed, this is where it will rub. Check the clearance here with your current tire, and extrapolate to a wider tire. Put the jack under the lower arm and raise the wheel up with and turn it all the way left and right and note where it comes closest. Anecdotally, I have heard that a 225/60-15 is right at the edge — might rub and might not. You don't have the stainless wheel well trim so that gives you a little extra room. Like your car, BTW.
Thank you for the information. I really appreciate the advice.
 
My 69 Barracuda takes a 4.5" backspace with 0 offset on a stock 8 3/4 SBP rear and stock suspension. You safely have 5.5 inches from the front of the drum to the leaf spring and an almost identical distance from the front of the drum to the wheel well lip. So your 4 1/8" (4.125) backspace with a 3 mm+ offset would equal 4 1/4" total backspace, or very close. You're definitely safe with those rims. Now, don't sell yourself short on rims due to the 5x4 bolt pattern. If you check American Racing Wheels (for example) they offer certain wheels as "custom". Those wheels can be done with the SBP and you set your backspacing and offset. AND.....you get a 17" or larger wheel which offers a lot more tire size options. I am waiting to get an order in but Covid has slowed everything down.
Thanks for the tip on the 17" wheels. Are you ordering them directly from American Racing? They have some very nice wheels.
 
A: i love Cragers, same set on both cars circa 1984
EPSON001 - Copy - Copy.JPG


EPSON002 - Copy - Copy.JPG


B: spend a few day or weeks thinking about how much you want to do the suspension. if you just want to go with some 1"+ T-bars, sway bars and shocks you'll be able to push the Radial T/A's your going to end up with right to their limit. and honestly, most people shouldn't drive harder than that on the street anyway...but if you got the bug to really make it handle, you're going to end up going 4 1/2" bolt pattern, to get the bigger upper ball joints, so you can do after market upper control arms to get more caster. so you'll need new wheels. then you'll find the really sticky street tires are all 17" and larger.

but even on 15"s you can make that plenty fun to drive

enjoy the car :thumbsup:
 
Thanks for the tip on the 17" wheels. Are you ordering them directly from American Racing? They have some very nice wheels.
No, I’m in Canada so I use an auto parts dealer whose connected to American Racing. But I did all my shopping and decision through the American Racing Wheels website.
 
A: i love Cragers, same set on both cars circa 1984
View attachment 1715540093

View attachment 1715540094

B: spend a few day or weeks thinking about how much you want to do the suspension. if you just want to go with some 1"+ T-bars, sway bars and shocks you'll be able to push the Radial T/A's your going to end up with right to their limit. and honestly, most people shouldn't drive harder than that on the street anyway...but if you got the bug to really make it handle, you're going to end up going 4 1/2" bolt pattern, to get the bigger upper ball joints, so you can do after market upper control arms to get more caster. so you'll need new wheels. then you'll find the really sticky street tires are all 17" and larger.

but even on 15"s you can make that plenty fun to drive

enjoy the car :thumbsup:
Thanks for the great advice. That's pretty much what I am thinking. T-bars, strut rods and shocks for a couple of seasons. I got the car in the middle of March so I've done alot of thinking about it. Actually that's pretty much all I've been able to do because before I could register it New York State shut down the DMV. It's been killing me for 2.5 months I haven't been able to drive it except up and down the driveway. Tomorrow morning I'm finally able to drop off my paperwork to the DMV so hopefully in a few days I'll finally get her on the road. Looking forward to feeling her out.
 
Bringing back an old post. On the topic of 17s on a Barracuda, I'm interested in the 17" Coy or torque thrust wheels and am wondering what y'all think about 17X7 / 4.25 up front? is that enough backspacing or should something with at least 5" be better? Also im looking for a tire size that will clear stock fenders, what are you running? Im building a 67 notch back with disc brake conversion up front and an8.25 in the rear with stock leaf springs and drum brakes to be a reliable soon to be daily/weekend driver so Im not looking for anything crazy or complicated. I have scoured FABO with lots of differing opinion and looking to get a clear recipe for wheels and tires I can confidently purchase online and know I wont have any clearance issues. any and all input and pictures are appreciated. THANKS!
 
Bringing back an old post. On the topic of 17s on a Barracuda, I'm interested in the 17" Coy or torque thrust wheels and am wondering what y'all think about 17X7 / 4.25 up front? is that enough backspacing or should something with at least 5" be better? Also im looking for a tire size that will clear stock fenders, what are you running? Im building a 67 notch back with disc brake conversion up front and an8.25 in the rear with stock leaf springs and drum brakes to be a reliable soon to be daily/weekend driver so Im not looking for anything crazy or complicated. I have scoured FABO with lots of differing opinion and looking to get a clear recipe for wheels and tires I can confidently purchase online and know I wont have any clearance issues. any and all input and pictures are appreciated. THANKS!


A 17x7 with 4.25” of backspace will fit, but really doesn’t take advantage of the additional backspace you can run with larger diameter wheels. Basically it would limit you to a 225 wide wheel (brake kit dependent). On that note, what disk brake kit are you using up front? They can change the track width which changes the backspace you need.

In the back you can run up to a 275 on a barracuda with the stock spring locations, although depending on the car they can be a little tight. If you want to make it “easy” a 255 would fit all day long with plenty of clearance regardless of ride height as long as you get the backspace right. What is the 8.25” out of? Stock A-body?
 
Thanks for the reply. Im running a kit I got from CPP, nothing too fancy Im pretty sure its 73+ parts. Im not married to the width, pretty much whatever fits the best and doesn't rub. Im not sure what the 8.25 is out of I was told the 360 motor and rear end came out of an old dodge truck but its yet to be verified.
 
Thanks for the reply. Im running a kit I got from CPP, nothing too fancy Im pretty sure its 73+ parts. Im not married to the width, pretty much whatever fits the best and doesn't rub. Im not sure what the 8.25 is out of I was told the 360 motor and rear end came out of an old dodge truck but its yet to be verified.

Yeah, the CPP kit is just '73+ BBP disk stuff, so that makes the front easy. With 17's and the plan to make it a daily driver what I would look at doing is going 17x8" all the way around and running 245/45/17's. They'll clear pretty easily front and rear with the proper backspace, you can rotate tires, and 245/45/17 is a very popular size so you have a wide range of tire options, anything from autoX only 100 treadwear stuff to snow tires.

In the front a 17x8" with a 5.25" backspace will work great, I recommend these wheels so much I should get a commission...
vsw-141h5761gm6_xl.jpg

Vision Wheel 141H7865GM19 Vision American Muscle 141 Legend 5 Series Gunmetal Wheels | Summit Racing

In the back I'd need a measurement from the wheel mounting surface back to the springs to recommend a backspace since you don't know where the 8.25" came from and they're available in a bunch of different widths. If you lay a ruler across the face of the drum, where the rim would sit when bolted on, and run a tape measure back to the springs that would do the trick.
 
Ill pull the wheels off later this evening and get a measurement out to you. Those wheels look good. What are your thoughts about 5.5 backspacing for the front, seems a wider variety to choose from at that backspacing? the 245/45/17 tire sounds about right. thanks for your help
 
Kind of doing it in reverse order. You need to make your mods first. Obviously you will not be using the stock brakes front or rear so the bolt pattern is moot. It will now be the standard pattern. 5 on 4 1/2. so wheels selection will be unlimited. Cragar S/S is not a performance wheel. Maybe in the sixties/seventies but that was before radial tires and ultra low profile tire were made. The suspension is a combination of the control arms, shocks, tires, wheels etc... You need to plan out the total combination from the start.
Like buying a cam and not knowing what induction, exhaust gearing, weight etc...you are building for.
 
I have my mods done. Rebuilt the front suspension and the stance Where it needs to be, just waiting on shock. Rear leaf springs are fine. I waited to get here before I considered rims and tires because I knew the variables.
 
Ill pull the wheels off later this evening and get a measurement out to you. Those wheels look good. What are your thoughts about 5.5 backspacing for the front, seems a wider variety to choose from at that backspacing? the 245/45/17 tire sounds about right. thanks for your help

5.5” of backspace for the front is fine, that should work great. With a 17” rim the backspace limit is usually around 5.6”-5.7”, right around there is when the outer tie rod end starts to become a clearance problem. It does depend a bit on the style of the rim, but if you stay under 5.6” on the backspace with a 17” rim it should clear fine.

With 18’s the outer tie rod actually fits inside the lip of the wheel, which is why 18’s allow even wider front tires (275’s!). But for 245’s or 255’s 17’s work great.

Kind of doing it in reverse order. You need to make your mods first. Obviously you will not be using the stock brakes front or rear so the bolt pattern is moot. It will now be the standard pattern. 5 on 4 1/2. so wheels selection will be unlimited. Cragar S/S is not a performance wheel. Maybe in the sixties/seventies but that was before radial tires and ultra low profile tire were made. The suspension is a combination of the control arms, shocks, tires, wheels etc... You need to plan out the total combination from the start.
Like buying a cam and not knowing what induction, exhaust gearing, weight etc...you are building for.

Actually I disagree wholeheartedly.

I always start from the tires I want to run. They decide everything else.

For example, if you’re building a car for handling and you decide you want to run 275mm wide tires up front with a 200 treadwear rating, that sets the wheels and suspension. You need 18” rims to do that, for example. Then you’ll have a ton of grip, so you’ll need larger diameter torsion bars. To get the alignment right for large torsion bars and wide modern tires you need tubular upper control arms. With that level of grip you’ll need a sway bar, chassis stiffening, etc.

On the flip side, if you want 225/60/15’s up front on a stock looking wheel, you can run pretty much all factory components with a few minor tweaks (offset UCA bushings, for example). You can benefit from larger torsion bars than stock because all of these cars can, but you don’t have to go crazy because you’ll be tire limited.

So if you’ve already set your suspension before you’ve picked your wheels and tires, you may have set yourself up for failure. Or at least locked yourself into a path already. If you rebuild all the stock components and throw a set of 18’s with 275’s on there you’ll be buying all new suspension again when you realize stuff hits, the alignment is wrong and the body roll is ridiculous because you done have the wheel rate to control that amount of grip. If you build some high dollar suspension and toss 225/60/15’s on there you’ll have wasted a ton of money, because you don’t have the grip to put any of that stuff to work and you’ll just slide around before the suspension gets going.

Sure, you have to know what some of your suspension will be to get the wheel offset right, but realistically the brake kit usually sets most of the track width. And the tire width determines where the tire has to sit, so you have to know that already too. And your brakes may be tied to the wheel diameter too! In my case, my wheels, tires and brakes all had to happen at the same time. My 13” brakes won’t take a 15” rim, and my 275/35/18’s and 18x9’s won’t fit the stock disks without a spacer because they have extra backspace for the additional track added by the 13” brakes. And because of that backspace they need a tubular UCA to clear the control arm at steering lock. So all of that happened at the exact same time. But I knew what I needed because I knew what tires I wanted first, and everything else fell in behind that. With a less extreme set up you can get away with some things, but really everything in the suspension and chassis starts from how much grip your tires have.
 
Kind of doing it in reverse order. You need to make your mods first. Obviously you will not be using the stock brakes front or rear so the bolt pattern is moot. It will now be the standard pattern. 5 on 4 1/2. so wheels selection will be unlimited. Cragar S/S is not a performance wheel. Maybe in the sixties/seventies but that was before radial tires and ultra low profile tire were made. The suspension is a combination of the control arms, shocks, tires, wheels etc... You need to plan out the total combination from the start.
Like buying a cam and not knowing what induction, exhaust gearing, weight etc...you are building for.

I can see what you are saying Mopar Leo because I can see clearly because I don't smoke a lot of pot while I'm at work in a California weed shop.

You are saying plan your suspension to reach your goal, do it once and save your money. I see a lot of guys throwing 15" cop car rims on their car, then another set of maybe 16" or 17" rims but it was never really the 18" rims they wanted to begin with that fit the brake package you wanted to begin with. I get ya, and I agree. It saves you money in the long run.

But reading posts on here most people will answer the same question over and over and over... "Will 15" x 6" rims fit on my car?"

The most important thing is to do what you want with your car and have fun and reach
 
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72bluNblu thank you for your detailed replies and great explanations, they are a big help for many of us who look to this forum for sound advise and experiences. I measured my 8.25 rear end and its about 56.5" from drum face to drum face. I also measured 5.5" from drum face to leaf spring and 6.25" from drum face to inner fender. any thoughts as to what would fit best? Thanks again!
 
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