Biggest tire under a stock suspension dart????

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I'm also running 255/60/R15 on a 15X7 wheel with 4 1/4 BS on stock springs. Not sure if I could get a bigger tire under there but there is still a little room on each side and it never rubs.
 
1972 dart - I run 15x8 with 4.5" BS and BFG radial t/a 255-60-15, stock a-body 8 3/4" rear and have a middle finger worth of space between both the leaf springs and quarter lips. 27" tire fills in great back there too...it doesn't look too fat or goofy..
 
Dads friend is runnin 295-75-15 with offset shackles and XHD 2 inch lift springs and I think custom wheels all in factory wheel tub. I can ask him
 
71DodgeDemon340 said:
Im runnin 275/60R15's on the back with no trimming at all.
8 3/4 rear, stock springs, 3:55 gears 400hp with a pinion snubber.
she only spins for about 5-10 feet then she goes.

:burnout:

Factory Undercoat :thumblef:
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I am running a 68 dart gt with a 8 3/4 rear end with super stock springs. I have a brand new set of 14x7 sbp cragar s/s wheels. I need to desperately find out what size tires I can run under my car without any modifications to the body, offset shackles, etc. nothing at all no modifications. the cragars are regular stock offset sbp. I have asked this on here before and got 100 different answers. I know that there is someone on here that can nail it dead on. as always I look to my mopar family for their help and understanding. there is so much knowledge here on this board that I know there is someone that can answer this. I hope I am not asking for too much. thanks brian
 
scampman said:
I am running a 68 dart gt with a 8 3/4 rear end with super stock springs. I have a brand new set of 14x7 sbp cragar s/s wheels. I need to desperately find out what size tires I can run under my car without any modifications to the body, offset shackles, etc. nothing at all no modifications. the cragars are regular stock offset sbp. I have asked this on here before and got 100 different answers. I know that there is someone on here that can nail it dead on. as always I look to my mopar family for their help and understanding. there is so much knowledge here on this board that I know there is someone that can answer this. I hope I am not asking for too much. thanks brian
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You'll see a bunch of different answers because it really depends on YOUR car. The body tolerances on these cars wasn't that great from the factory, so having wheel tubs that are a 1/4" different from one car to another is common. Heck it's not uncommon for the SAME car to be off by a 1/4" from the right side to the left side. That can easily be the difference of whether a certain tire combination fits or not. Pre-'70 cars seem to be a little tighter for clearance as well, so you have to pay attention to the year too. Also, you can only look at Dart's or Scamp's. Many of the replies above are Duster's, demon's and Barracuda's, and all of them can fit a 275 with no mods at all. That bodystyle has an extra inch in width in the wheel tubs compared to a Dart or Scamp, and that's in comparison to my '71 Dart. Even the pre-70 Valiant's aren't a good comparison, because they have a higher wheel opening. The low opening on a Dart means you have to clear the widest part of the sidewall even on cars that sit high in the back.

Next we have to know the exact backspacing. "Stock" sbp backspacing for an aftermarket wheel doesn't say much. Cragar S/S's have come in a bunch of different backspaces for a 14x7, and they can be anywhere from 2.75" to 4.125" right off the shelf.

Finally, if you absolutely don't want to do anything to the body, the absolute widest I'd recommend is a 245, and that's if the backspacing is perfect. Some folks have managed to get 255's on some Dart's with stock spring locations and no mods, but other's have had them rub. So, I wouldn't buy a set of 255's unless I was willing to do some fitting and trimming. And really it's probably moot because I can't find a 255 for a 14" rim with the right profile anyway.

So, with everything in the stock locations and no trimming or modifications, even with the proper backspacing, you're probably stuck with a 235 or 245 at best.
 
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pntastar69 said:
-- Gonna be tough w/an 8" wheel unless you get a special offset and install the offset leafspring set up. --
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-- Yep ! -- Here's My 68 Dart with 8" modified BS (Don't remember the offset inches), and offset spring set up. -- 275/60-15" BFG tires. --SS Springs.
Dart - 68 - 2.JPG
 
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255/60/15 rear leaving about 1/2 inch till the springs are there, 235 on the front on till I but disc brakes on it then I had to go to a 205/60/15
 
tekslk said:
255/60/15 rear leaving about 1/2 inch till the springs are there, 235 on the front on till I but disc brakes on it then I had to go to a 205/60/15
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On a Dart? Because if it's on your Barracuda that's a whole different ball game.
 
ride height makes a huge difference to. Id the *** end is sky high you can get more tire "under" it. I prefer tires tucked in.
 
*** not jacked on my barracuda but isn't the barracuda and dart about the same?
 
Any tire shop worth their salt will be happy to work with you, on the rack, to figure out which tire will work best for you. Show up with your car and your rims and they will mount tires till your happy. They have a product that they want to sell. Even better, if you can find a time of day/week when they are a bit slow. This will take all the guess work out of it. Good Luck and remember to report back on your experience.
 
tekslk said:
*** not jacked on my barracuda but isn't the barracuda and dart about the same?
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THIS IS WHY I REGARD YOU GUYS AS FAMILY. YOU ALL BANDED TOGETHER AND GAVE ME ALOT TO THINK ABOUT. I REALLY APPRECIATE ALL THE IN DEPTH INFORMATION YOU HAVE SUPPLIED ME WITH. KEEP THEM COMING AND WHEN I GET THE WHEELS AND TIRES ON IT I WILL POST SOME PHOTOS OF IT. THANK YOU ALL SO MUCH FOR YOUR INPUT. RESPECTFULLY YOURS, BRIAN (SCAMPMAN)
 
these were on the back of my 69 gt dart . 15x8x4bc 1/2'' neg offset with a 225/70 on them .
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tekslk said:
*** not jacked on my barracuda but isn't the barracuda and dart about the same?
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Nope! Barracuda's and Dart's are not about the same for tire clearance. Not even close.

Barracuda's have over an inch more room to the quarter than Dart's do. A stock barracuda can easily fit a 275, you can't even get close with a Dart. On most Dart's there's usually about 12" from the inner wheel tub to the quarter lip, on a Barracuda that number is usually a little over 13", which is similar to a Duster, Demon, or Dart Sport. That doesn't account for the springs, which are in the same place on all of the A-bodies. For example, on my '71 Dart there's about 11" from the spring to the quarter lip, that's with the springs in the stock locations and uncut quarter lips.

That's why a 245 is about as wide as you want to go on a Dart with the stock spring locations, because the section width on a 245 is generally 9.8" to 10" depending on the manufacturer (they're not all the same!). So, if perfectly centered you'd only get a 1/2" clearance to the spring and the quarter. The spring clearance is fine, but a 1/2" to the quarter is about the minimum you can get away with without rubbing during normal driving conditions (corners, speed bumps, passengers in the back seat etc). A 255 typically has a section width of about 10.2", which makes it REALLY tight. You still need a 1/2" to the quarter to keep from rubbing, and that only leaves a 1/4" to the springs, which really isn't enough for the tall sidewall on a tire for a 14 or 15" rim . If you trim the quarter lips back it usually works, especially on cars that sit high in the back. But on a bone stock car with stock spring locations and ride height it's not likely to work. And some cars were blessed with a little more clearance from the factory.
 
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70 Dart, 8 3/4, Has 255 60 15s, with a 4.25 backspace. Could fit a 275 60 15 with fenders rolled but it would be tight (On my car atleast). So, just purchased a set of Mickey ET streets. 255 60 15s On a 8" rim with 4.5 backspace.
 
Any tire with a 9.65 section width will fit on a dart with stock suspension. 10.5 section width fits under an offset shackle car with stock tubs. 13.1 fits under a relocation kit car.
 
SoulSurvivor said:
I have a set of 255-60R-15 Mickey Thompson ET street tires mounted on a 15x8 rim with a 4-1/4" backspace. I also have the MP SS springs. There is a 1/4 inch clearance from the inside of the tire to the leaf spring and about 1/2 inch of clearance to the fender. Air down the tires to18lbs and you will get good traction. I too have 3.91 sure grip. And a 340 that dyno'd at 410hp. Hope this helps.
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Are your springs in the stock location?
Thanks
 
255/60-15 on 15x7 with a 4.25 backspace. No trimming but quite close on 1 side.

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