Biggest tire under a stock suspension dart????

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swinger340

swinger340

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Looking for the widest 15" tire (about 26-27" tall) on a 8" rim that I can put under a 69 Dart with stock suspension. Looking for pics as well if you have some. After putting my new 428HP 340 in my 69 swinger. 4 speed w 3:55s and 235/60/14s it has major traction issues. Thinking wider, taller tire with 3:91s will help
 
With the stock springs? Not very big. I tried a test fit with my 275/40/17's on the back of my stock suspended '71 and found they contacted both the spring AND the quarter at the same time. They'd fit with a 1/2" or 3/4" hanger/shackle spring offset, but not stock.

I'd guess that a 255 is about as wide as you can go without an offset kit or a relocation kit unless you jack the rear end way up. A 255/60/15 would be 27" tall, although you might have to trim the corners of the quarters to make a 27" tire work.
 
why would you want a stock rear suspension with 400+ hp anyway ??? .... i have 255/60r15 but running 002/003 ss springs ... no clearance issues at all ...70 dart 340/4spd
 
65-440 said:
why would you want a stock rear suspension with 400+ hp anyway ??? .... i have 255/60r15 but running 002/003 ss springs ... no clearance issues at all ...70 dart 340/4spd
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I plan on upgrading to SS springs and poly bushings next summer, have even considered cal-trac. Its a real 340 4 speed car so im not going to mini tub, alter the body or anything like that. I have all the #s matching stuff(engine, radiator, carb, exhaust), because im a resto fag #s guy. lol!!! Just in case I ever decide to put it back to original, or sell.
 
Snake said:
I bet an adjustable pinion snuber would help.
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I bought an adjustable MP snuber off of a fello FABO member. Plan on installing that at the same time I put the 3:91s in and the bigger tires on. My stock suspension is in great shape. Car still has original brake lines. Im the 1st to have it on the rd since 1973. Car only has 35K on it. Sat in a daylight basement since 73. Guy who bought the car new never made it back from Vietnam and his parents could never sell the car. I only got it after the parents passed in the late 90s. I made some people mad, because others had been trying to buy the car for years. rite place rite time.
 
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.
 
SoulSurvivor said:
I have a set of 255-60R-15 Mickey Thompson ET street tires mounted on a 15x8 rim with a 1-1/4" 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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Yes that does help. After looking at some pics, it looks like 255/60/15s it is. I didn't want to buy new tires and have them not fit. Thanks for the info.
 
i just put on 26 x 10.00 slicks on mine they fit but you have to doo some adjusting to get them there.....oops they are mounted on 15 x 7 cop wheels...
 
Mine are 225/75 x 15, and they barely fit. As you can see, mine is up a little as I added the largest leafs from two spring sets together. These are 28" tall. These come VERY close to the front wheel lip, and sometimes rub a little on a VERY hard right corner, but not very often

xbzott.jpg
 
Heh.........thanks but it doesn't look that good in person. "It's a driver" and needs paint badly. But it's been painted 87 times and is about 1/4" thick. Cleaning it up will require a full -- tear down, something I don't have money for.
 
Be careful with 255/60R15 on an 8" wide wheel with 4.25" B.S. My friend has this combo on his 69 dart and the tires rub on the rolled fender lip. I am running that tire size and wheel B.S but on 7" wide rims and I have plenty of clearance from the springs and fender lip. Some tires bulge more than others. I have BFG but maybe the Mickey Thompson's don't bulge as much giving some more clearance.
 
gold68dart said:
Be careful with 255/60R15 on an 8" wide wheel with 4.25" B.S. My friend has this combo on his 69 dart and the tires rub on the rolled fender lip. I am running that tire size and wheel B.S but on 7" wide rims and I have plenty of clearance from the springs and fender lip. Some tires bulge more than others. I have BFG but maybe the Mickey Thompson's don't bulge as much giving some more clearance.
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15x7, 4.25bs ... 255/60r15 BFG's here .... plenty of room !! ... think i can go a tad bigger ! ..
 
My 67 cuda has 7 inch wheels 255/60 15 inch I have 3/4 in to the springs and all kinds of room every where else.
 
I'm running 255/60-15 Mikey drag radials on the back of my 68 GTS. They are mounted on 15X7's with 4.5" backspacing. Clearance all around without rolling fenders. I did put a 1/2" spacer between the front hangar and the body just to center the wheel better.
 
Gonna be tough w/an 8" wheel unless you get a special offset and install the offset leafspring set up. A 7" wheel as mentioned will work fine. Get youself a pair of Caltracs for almost the same as a set of tires. They'll cure your traction problems specially w/a stick car.
 
pntastar69 said:
Gonna be tough w/an 8" wheel unless you get a special offset and install the offset leafspring set up. A 7" wheel as mentioned will work fine. Get youself a pair of Caltracs for almost the same as a set of tires. They'll cure your traction problems specially w/a stick car.
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I had full caltracs setup on my '65, loved them but super hard on the street !
 
65-440 said:
I had full caltracs setup on my '65, loved them but super hard on the street !
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Could you expain further regarding caltracs "being super hard on the street"?

70 and up Darts also have way more room for tire clearance. Wheel lip is much higher than 67 - 69 Darts.
 
AdamR said:
way more room on a Barracuda or Duster then a Dart
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Absolutely... Id trade for a 68-69 fastback barracuda. Problem solved. LOL!!! I also mislead everyone on the 8" rims. I thought they were 8s but after a closer look they are actually 7" w 4.25 backspacing steelies w the 9" center for my red line dog dig wheel covers.
 
NO PHONE NUMBERS PLEASE this guys name is greg ,i bought my dana and some brackets to fix the same problem your having ...it mite be worth giving him a call....i havent installed mine yet so i cant tell you if it works or not but the brackets were around 150 bucks..he said i could run 275 60 15 with 8 in wheels at 4.5 offsett to the best i can remember...the stuff i got looks nice and professional ....
 
235/60 MT streets on a 71 Scamp there is just enough room, also ran 26/8.5 slicks and that was tight, all this on 7 in steel wheel.
 
I have 18x8 centerlines on my 71' dart with a 5" backspace. I couldnt get anymore rim under the car if I wanted. I measured over and over to find the max size to fit. I couldnt have gotten a better fitting rim. I dont have any picks maybe I could get some up soon.

Now my car was an origonal /6 converter to a v8. Converted over for the previous onwer. Im not sure if there is any track difference in the 8-3/4 that was put in the car. So that may have an effect on backspacing. but none the less the springs are in the same spot and they would be the first to hit the tire/rim anyhow. I did debate relocating the springs but it was only going to gain me maybe a 1/2" before running out of inner wheel well and need to mini tube her. So I didnt see the point.

I run a Nitto 555's 245/45 18 on the rims on all fours which are 26.5" in diameter. @ the track I used a set of 26x8 hoosers on a summit racing 15x7 rim with 4" backspacing I believe.
 
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