Tire Size 68 Barracuda

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SGlez10

68 Barracuda
Joined
Sep 17, 2020
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Location
Carson, Ca
Hi guys

I have a 68 Barracuda Notchback.

8 3/4 rear end. Stock leaf springs.

What are the biggest tires I can fit front and back without any rubbing issues. No modifications.
 
What size rims?

With 15’s you’re looking at 225/60/15’s in the front and 275/60/15’s in the back if no mods is the goal. 235/60/15 up front has been done, but that’s not really a “no mods” situation.

With 17’s, 245/45/17’s up front and 275/40/17’s out back. I’d say 255/45/17 up front but the lower front corner of the fender would be an issue.

With 18’s, 275/35/18 front and rear can be done, but in the front the lower front fender corner would need to be dealt with. Otherwise probably 245’s up front again.

The wheel opening in the front fenders is an issue with taller tires, gets to be an issue around 25.6” and taller especially with wider tires.

And of course for wheels that will actually let you do any of that we’d need to know the bolt pattern and brakes you’re running. Backspace changes a bit with the larger bolt pattern brakes.
 
@72bluNblu is pretty much bang on with the 15” recommend(s)(and of course his 17&18" recommends), I’d add that after going through this on my last three A bodies that each of them can easily be different by+/- a 1/2 inch or so on it’s ‘available’ clearances Due to factory assembly inconsistencies.

On the rear- 275/60’s with an 8" - 8.5” wheel requires bang on backspacing at around 4.5 MAYBE EVEN 4.75” (up to 4 7/8” may work - this was a common Centerline backspacing) and even then you had better hope the diff is perfectly centred on the factory welded perches as it can get really close to the LEAF SPRING when you factor in sidewall bulge. Another sensitive area on the rear is the BOTTOM FRONT portion of the the REAR WHEEL OPENING. I’ve had some with basically no clearance and others with about 1/2". Some people shim the front spring mount to move the diff back a little to make the clearance more here. If I shimmed (which I haven’t) I’d use a solid piece of steel, don’t just build it up with washers. The last area of concern is the WHEEL OPENING LIP and the inside wheel house, kind of self explanatory here, 275’s in an 8” should clear the lip but it’s close. 9 and 10” wheels makes fitment even more difficult. On each case for me I never ended up using 275’s as I just couldn’t get a happy amount of clearance in the areas mentioned so opted for 27” x 10” rears (P255/60R 15’s)

On the front- I have found that about the most I can get in is a 26” tall tire. On this car a P215/60R15 was used and I have about, Maximum 3/8“ one one side and maybe a tad more on the other side clearance on the BOTTOM FRONT WHEEL OPENING and also at the REAR OPENING TOO, also where the fender bolts into the car about 8 inches up from the bottom Opening
Wheel width and backspacing is KEY on the front. You need the perfect formula to get the tallest tire you can in here. Which also can dictate the max size tire too. 235/60’s we’re definitely a NO go- too wide…..the height of a 225/60 should be okay but the extra width in the 225/60 vs a 215/65 can make it real close again too - it’s a bit of a juggling act between these two sizes and for me I preferred the height of the narrower taller 215/65 to achieve a 27” rear and 26” front staggered effect. 215/60’s fit with ease but looked too dinky…

for the record my rims dimensions on THIS car are:

15x8 rear with 4.25" back spacing and 4.75" outward or front spacing so to speak.
15x6 front with 3.75" back spacing and 3.625" outward or front spacing so to speak.

you’ll notice that if the rear and front spacing values are added together it equals an inch more than the rim width. When measuring back and front spacing you include the the lip of the rim into the value.

tires are:

P255/60R15 rear
P215/65R15 front

you could likely use a 7" wide rim on the front but would HAVE TO increase the amount of rear backspacing in order to make them work. The only issue here when you go to much rear spacing is inner fender well rub and potentially control arm interference etc.

good luck with your choices! Post a picture when done.

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IMG_3082.jpeg


IMG_3081.jpeg
 
What size rims?

With 15’s you’re looking at 225/60/15’s in the front and 275/60/15’s in the back if no mods is the goal. 235/60/15 up front has been done, but that’s not really a “no mods” situation.

With 17’s, 245/45/17’s up front and 275/40/17’s out back. I’d say 255/45/17 up front but the lower front corner of the fender would be an issue.

With 18’s, 275/35/18 front and rear can be done, but in the front the lower front fender corner would need to be dealt with. Otherwise probably 245’s up front again.

The wheel opening in the front fenders is an issue with taller tires, gets to be an issue around 25.6” and taller especially with wider tires.

And of course for wheels that will actually let you do any of that we’d need to know the bolt pattern and brakes you’re running. Backspace changes a bit with the larger bolt pattern brakes.
Sorry I left that out.

14inch wheels.
 
@72bluNblu is pretty much bang on with the 15” recommend(s)(and of course his 17&18" recommends), I’d add that after going through this on my last three A bodies that each of them can easily be different by+/- a 1/2 inch or so on it’s ‘available’ clearances Due to factory assembly inconsistencies.

On the rear- 275/60’s with an 8" - 8.5” wheel requires bang on backspacing at around 4.5 MAYBE EVEN 4.75” (up to 4 7/8” may work - this was a common Centerline backspacing) and even then you had better hope the diff is perfectly centred on the factory welded perches as it can get really close to the LEAF SPRING when you factor in sidewall bulge. Another sensitive area on the rear is the BOTTOM FRONT portion of the the REAR WHEEL OPENING. I’ve had some with basically no clearance and others with about 1/2". Some people shim the front spring mount to move the diff back a little to make the clearance more here. If I shimmed (which I haven’t) I’d use a solid piece of steel, don’t just build it up with washers. The last area of concern is the WHEEL OPENING LIP and the inside wheel house, kind of self explanatory here, 275’s in an 8” should clear the lip but it’s close. 9 and 10” wheels makes fitment even more difficult. On each case for me I never ended up using 275’s as I just couldn’t get a happy amount of clearance in the areas mentioned so opted for 27” x 10” rears (P255/60R 15’s)

On the front- I have found that about the most I can get in is a 26” tall tire. On this car a P215/60R15 was used and I have about, Maximum 3/8“ one one side and maybe a tad more on the other side clearance on the BOTTOM FRONT WHEEL OPENING and also at the REAR OPENING TOO, also where the fender bolts into the car about 8 inches up from the bottom Opening
Wheel width and backspacing is KEY on the front. You need the perfect formula to get the tallest tire you can in here. Which also can dictate the max size tire too. 235/60’s we’re definitely a NO go- too wide…..the height of a 225/60 should be okay but the extra width in the 225/60 vs a 215/65 can make it real close again too - it’s a bit of a juggling act between these two sizes and for me I preferred the height of the narrower taller 215/65 to achieve a 27” rear and 26” front staggered effect. 215/60’s fit with ease but looked too dinky…

for the record my rims dimensions on THIS car are:

15x8 rear with 4.25" back spacing and 4.75" outward or front spacing so to speak.
15x6 front with 3.75" back spacing and 3.625" outward or front spacing so to speak.

you’ll notice that if the rear and front spacing values are added together it equals an inch more than the rim width. When measuring back and front spacing you include the the lip of the rim into the value.

tires are:

P255/60R15 rear
P215/65R15 front

you could likely use a 7" wide rim on the front but would HAVE TO increase the amount of rear backspacing in order to make them work. The only issue here when you go to much rear spacing is inner fender well rub and potentially control arm interference etc.

good luck with your choices! Post a picture when done.

View attachment 1716096620

View attachment 1716096621

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View attachment 1716096623
Very nice stance.
 
Sorry I left that out.

14inch wheels.

Factory 14” wheels? What widths are we talking here? Because most likely the biggest tires will be completely dictated by the width of those rims.
 
Factory 14” wheels? What widths are we talking here? Because most likely the biggest tires will be completely dictated by the width of those rims.
I’m going to have to measure bc I’m not sure. I’m not fluent in this topic as many of you guys so I’m doing my best. Here is my car now. Definitely would like to put 245 in the rear but again, not sure if they’d rub or not.

F9AF9EE7-25E9-4F91-990A-4448883743A5.jpeg


6F4746CE-1663-44AF-989B-EF61A88B7195.jpeg
 
Great looking car! :thumbsup:

Based on your pictures, I'd say you're already running the biggest tires you're going to make fit with that set of rims. At least really close to it. What size tires are on it now?

A 245/60/14 needs a 7" wide rim, and I would wager that's not what you have on there at the moment. Even if it is, it looks like you'd need more backspace that you currently have to make it work.
 
I’m going to have to measure bc I’m not sure. I’m not fluent in this topic as many of you guys so I’m doing my best. Here is my car now. Definitely would like to put 245 in the rear but again, not sure if they’d rub or not.

View attachment 1716096704

View attachment 1716096705
Great looking car! :thumbsup:

Based on your pictures, I'd say you're already running the biggest tires you're going to make fit with that set of rims. At least really close to it. What size tires are on it now?

A 245/60/14 needs a 7" wide rim, and I would wager that's not what you have on there at the moment. Even if it is, it looks like you'd need more backspace that you currently have to make it work.
Right now I have 215 in the back and 195 in the front but both are leaving plenty of space. I’ll send more pictures later when I get home.
 
These are stock 14 x 5.5 wide factory steel wheels with BF Goodrich 235's on all 4 wheels on my '69. No rubbing or hitting front or rear.

10271164_10201280840617879_7130471771744805068_o.jpg
 
If you read the tire manufacturers' recommendations, the widest tire you can fit on the stock HD 14 x 5.5" wheels is 215 (so, 215/70-14). If you have the standard 14 x 4.5" wheels, it would be 205/70-14.

I am assuming A56 is running 235/60-14 because 235/70 would never fit, and I don't think anyone makes one, anyway. But 235 is technically too wide for the rims.
 
If you read the tire manufacturers' recommendations, the widest tire you can fit on the stock HD 14 x 5.5" wheels is 215 (so, 215/70-14). If you have the standard 14 x 4.5" wheels, it would be 205/70-14.

I am assuming A56 is running 235/60-14 because 235/70 would never fit, and I don't think anyone makes one, anyway. But 235 is technically too wide for the rims.

Exactly.

Can you cram wider tires on there? Sure. Of course squeezing it on there will deform section width and the tread pattern, so then you have to run lower tire pressures if you want to improve the contact patch. And then the sidewalls get floppy, so you lose handling performance. So you get to say you're running wider tires, but really you're not gaining any kind of actual performance compared to just running the right size tire for the rim on there.

Assuming of course you can find an installer that will install them. And then there's any kind of warranty, and just because they installed it doesn't mean they'll honor the warranty later when you bring the tire in 'cause the tread is wearing funny.

Follow this with a bunch of posts saying " I did it and it worked fine because I'm not dead", because plenty of people never drive anywhere near the capabilities of even the hockey puck hard, all-season "performance" radials that will no doubt be used, and probably "time out" their tires rather than actually wear them out. But hey, they definitely know more about tires than the people that actually make the tires.
 
If you read the tire manufacturers' recommendations, the widest tire you can fit on the stock HD 14 x 5.5" wheels is 215 (so, 215/70-14). If you have the standard 14 x 4.5" wheels, it would be 205/70-14.

I am assuming A56 is running 235/60-14 because 235/70 would never fit, and I don't think anyone makes one, anyway. But 235 is technically too wide for the rims.
Yep, 235 60 14
Below is the manufacturers recommendation

Product Identifiers​

Brand
BFGoodrich
Manufacturer Part Number
38765
Model
Radial TA
eBay Product ID (ePID)
24056261160

Product Key Features​

Overall Diameter
25.1in
Section Width
235
Load Index
96
Speed Index
S
UTQG
400 A B
Features
Raised White Letters
Tread Depth
11/32in
Tire Type
Touring
Rim Diameter
14
Aspect Ratio
60

Additional Product Features​

MAX Inflation Pressure
35psi
Rim Width MAX
8.5in
Tire Size
235/60r14
MAX Load
1565lbs.
Rim Width Min
6in
Tread Tire Type
P
Revs Per Mile
828
P Metric
 
Just got the front end done. Now measuring for rims and tires.
68 fastback
Front 73+ slider disc brake conversion (rotor hat to hat 58 7/8) and Hellwig sway bar. All bushings new and stock.
Rear 54 1/4 B body 8 3/4 with dic brake conversion ( rotor hat to hat 60”)
Was thinking Torq Thurst M chrome 17x 8s with 5.68 bs 235/45/17 ft and 255/45/17 rear.
I think by my calculations it should work. Any input would be great. Or even other options/ suggestions.
Thanks all !
Toying with burnt copper calipers. Input lol.

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IMG_1318.png
 
I’m going to have to measure bc I’m not sure. I’m not fluent in this topic as many of you guys so I’m doing my best. Here is my car now. Definitely would like to put 245 in the rear but again, not sure if they’d rub or not.

View attachment 1716096704

View attachment 1716096705
Hi guys

I have a 68 Barracuda Notchback.

8 3/4 rear end. Stock leaf springs.

What are the biggest tires I can fit front and back without any rubbing issues. No modifications.
The front I run 205 70 15 and the rear i run 15x7 with 4.25 backspace small bolt pattern 255 60 15 anything bigger than that it looks like a hot wheel lol

Hit up Collins wheels ask for Carlos he can make you any width and back space small bolt or big bolt pattern he is is bell flower tell him Moe sent you!
 
Tony, I like your mustang rims idea (that what the 'M" stands for).
In my humble opinion, too much backspace is MUCH more desirable that not enough. Then a quality spacer (billet, not the cast crap) can be used to put the wheel and tire exactly where you want it.
The m rims are probably perfect for the rear with discs on a b-body rear, might need a spacer on the front. Then it will come down to tire size selection.
 
Just got the front end done. Now measuring for rims and tires.
68 fastback
Front 73+ slider disc brake conversion (rotor hat to hat 58 7/8) and Hellwig sway bar. All bushings new and stock.
Rear 54 1/4 B body 8 3/4 with dic brake conversion ( rotor hat to hat 60”)
Was thinking Torq Thurst M chrome 17x 8s with 5.68 bs 235/45/17 ft and 255/45/17 rear.
I think by my calculations it should work. Any input would be great. Or even other options/ suggestions.
Thanks all !
Toying with burnt copper calipers. Input lol.

View attachment 1716207562

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View attachment 1716207569


Backspacing on the wheels is pretty much spot on front and rear. The back should be fine with the 65-67 B-rear and disks with the stock spring locations. You can probably go wider in the back pretty easily.

In the front the 5.68” backspace is right at the limit of what will clear the outer tie rod end. It will depend on the actual design of the rim, but if it’s close it won’t take much of a spacer to clear it.

The 235/45/17 will fit the car easily, you can go wider and taller if you wanted.
 
Didn’t know that’s what the M was for. Not my first choice just seems the back space worked. I wanted something a little more modern but it’s the bs that’s getting me. But the want a fortune for custom bs.

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On rears I have 7 1/8 to spring but again custom bs is the killer.
Also will only drive it on Sundays lol just little 318.

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I have to have more bs. I only have 3 7/8 to fender lip but 7 1/8 to leaf spring. That’s because of the b body 8 3/4.
 
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