View Full Version : How big of a tire will fit my Swinger without tubs?

Brian C
02-23-2000, 02:13 AM
Could somebody help me take the guesswork out of finding out how large of a slick will fit under my 72 Dart Swinger without cutting up the quarters, or the wheel wells? I would like to fit a 29.5x10.5x15 if possible. Any reccomendations on rim width, backspacing, axle with, spring relocation etc.? Has anyone done what I am trying to do?
Christopher.....in case you read this, I got my pro parts headers yesterday! They sure are neat! I can hardly wait to get them in there! As long as I get this rear wheel stuffing issue resolved, I can hopefully get some traction with that big motor up front!
If anyone can refer me to someone who has info, please do, or E-mail me at: SOSS72@aol.com!
Thank You

02-23-2000, 03:09 AM
Those Tires should fit I have MT ET Streets 26X12.5X15 under my car and they clear the fenders. My cars sits very low and if yours sits standard height there should be no problem. On rims I would use 15X8 with 4.5 inches Backspacing. If your springs are mooved inward then you will easily clear all of this and not have any rubbing problems.

02-23-2000, 03:30 AM
i was under the assumption that 67- 72 darts all had the same wheelwells...? i know a 12.5 wouldnt fit in my 69 till i moved the springs and wells.

check out bigblockdart.com got another dart up now too. the wheelwell move will be up in a week or two.

Brian C
02-23-2000, 10:10 AM
Christian Cuda...thanks for the help. Are you using the standard width A body reazr axles and housing, and what size brakes do you have in the rear. The brake pad width/ and drum width also play a role I think? Please respond.
Thank You

02-23-2000, 03:17 PM
ChristianCuda must have had some work done to his rear or it was done before he got it.

I have a '75 Scamp and the largest tire I could get under there was a 28 x 9 with no room to spare on the inside by the frame or outside by the wheelwell. I'm using a 6.5" production ralley with a 1/4" inch spacer. This puts the tire 1/8" from the springs and a nose hair from the wheel well. With the slicks on, I have to be carefull making turns b/c they'll rub.

So as far as I know the tires you have are about 3 1/2 inches too wide unless you jack the car WTFU and that's not the answer. If you want a big tire just to have big tires, you're gonna have to do some work. If you're concerned about traction, I've run in the 10's with the 28 x 9 and had no traction problems at all.


Brian C
02-23-2000, 03:28 PM
Art:my car is actually a 73 Scamp. But many get confused on what a Scamp is. I am planning to run mid 10's. I am just concerned with big enough tires for traction. Several people claim they run that fast w/ a 28x9x15. I am just trying to eliminate guesswork! I am assuming you are using a standard A body 8.75 rear?

Thank you

The Dartman
02-23-2000, 03:35 PM
I think the 10.0's may fit, but take careful measurments of your car from axle flanges to any suspension componants, wheelwells, or anything else that a tire may rub. Then either take the manufacturers width measurments (tread width is unimportant, you really need side wall width) and calcalate exactly what rim sizes you need. On your Dart, you could run either 4 or 4.5 inches of backspacing as long as you don;t have overly large sidewalls. I would also recommend an 8 inch rim as well, since so many larger tires look and hook better with a larger rim.

I ran into a problem with my setup were I had a pair of Weld Wheels thAT were 7 X 15 X 4.5 and had a pair of 10 inch Mcreary Road Stars. The Road stars actually had a smaller tread width than the previous tires on these rims, but the larger sidewall put the tire into springs by about 1/4 inch. I then switched to a 7 X 15 X 4 inch rim and they fit fine - but my rims don't match when I drag race!!

The largest tire I've had on my Dart Sport (I know its a different animal) is a 11.5 inch JcPEnny BIAS ancient tire. I even had to modify my wheel lips a little to accomodate the larger tire, and even then it rubbed quite a bit.

A long time ago I saw in the Direct Connection Speed secrets book a section about "stock" mopars and the largest tires that can fit under a stock wheel well. They rated like this (from memory):

Largest: E bodies
Second Largest: B bodies
Middle: A bodies (Demon, Duster, Dart Sport, older cudas)
Smallest: A bodies (Dart, Valiant)

In the article they listed actual models and the largest tire/wheel combos that would work with them. So according to MOPAR you have the smallest wheel well opening for running large tires. As far as wanted to run a larger tire for traction, remember that there is cars running in the 8's and 9's on 9 inch slicks!! So I wouldn't get too excited if you can't seem to fit a tire over 10 inches wide under that wheel well.

I stress taking careful measurments of YOUR OWN CAR before buying tires or wheels. Another way is to find an UNMODIFIED car that is EXACTLY like yours and taking measurments and info down about the tire/wheel combo. The olds saying is now "Measure Twice - Buy Once".

'73 Dart Sport
318 CU, 12.5:1, "J" Heads, 517L/292D Camshaft
727 trans, 4500 Tci Converter back to 4.30 gears for a best of 12.87@105

[This message has been edited by The Dartman (edited February 23, 2000).]

02-23-2000, 03:38 PM
I havent done any tub work on the car but i did move the springs inboard slightly with the spring relocation kit. This only moves the front and not the rear of the springs though. And the fender lip has been trimmed and bent up. I didnt say that they fit with plenty room I said they fit and was using it as a reference to the 10.5 that where being asked about. I also said mine are 26 inch tall. They rub alot on that car but without the 12.5 inch wide the car wont hook right. I am using the a-body 8 3/4 with E-body 10.5X2.5 brakes and B-body replined axles. I have to replace tires more often because of the sides being cut than because the tread is worn out on my tires but they are still two inches wider than the ones asked about. The wheels I am not sure about, they are a set I had lying around here. They are 15X8 but I dont know the backspacing. I do know that in order to make a set of wheels fit properly though with 15X8 you will need 4.5 to 4.75 inches backspacing.

68 'Cuda 383 Working on adding EFI
69 'Cuda Race Parts Car
76 Duster 273 recent transplant
95 Neon 2.0 SOHC best of 16.96
84 Dodge Ram D50 transplanting 360

[This message has been edited by ChristianCuda (edited February 23, 2000).]

02-23-2000, 08:20 PM

I'm telling you that the 9" wide tire is the biggest you can get under there as far as I know without modification. I went through this on the Scamp for weeks, which by the way has a standard length 8 3/4 with drum brakes..... borrowing rims and tires and all sorts of combos. I didn't want a big ass tire just to have it, I just wanted the biggest thing that would fit.
Your best bet for maybe and I mean maybe getting a 10" tire is to use a wider rim than I did. Like, say a 7 or 7 1/2" rim. ( I know for a fact that a 9" rim, from bead to bead, rests on the spring and is dead level with the fender lip.)
This wouldn't make the tire buldge out so far like the 6.5" rims I have, which actually expands the cross section of the tire, but I seriously doubt that they'll fit safely. You ever had a tire blow out at 126 mph ? Me either and I don't want to find out.

Do this..... remove one of your wheels and measure from the side of the spring to the inside top of the lip and I bet it's not 10 1/2". Check it out and let me know. I can't remember.

FYI: I like the 14" rims. Most racers and rodders like the 15 and that's understandable b/c the tire selection is greater. However, I have found that using the 14" rim gives me more sidewall and a better wrinkle, therefore better traction. I have never, and I mean never had a problem with traction.
Some of you guys may say that I have no power and that's why I don't need big tires. Well, for a street car - registerd, inspected and tagged and driven to run 11's on motor and 10's w/N2O consitutes some power at least - just thought I'd nip that in the bud.
Anything with tires bigger than 12" wide better be runnin' some low 9's or you've wasted money on big tires for nothing. The most common mistake is putting big ass tires on when ya' don't need them. It's kinda like just buying the biggest cam you can get just to have it and it doesn't help. I guess you could say it's like getting a penis implant. It might be big and you think it looks good, but if ya' can't find someone willing to try that big ole thing out on, all you have is something to look at.


Brian C
02-23-2000, 10:05 PM
Good point ART! I am curious...did you relocate your springs inboard at all?

02-23-2000, 11:42 PM
Nope. Didn't want to have to fool with all that. If the car didn't hook up I would have had to for a bigger tire. But once again I found that the 28 x 9" tires were plenty.

Added info: '75 Scamp 400 ci, 8 3/4 SG, 4.56 gears, 727 with Cheetah manual valve body, 3500 stall (foot brake). The Scamp now has a 440 in it the 400 went boom - a casualty of too many rpm


02-23-2000, 11:59 PM
I had a 72 Swinger with Pro Trac P245/60R14's mounted to Cragar SS rims, 14 x 7" I think, in the back. I don't remember the backspacing, but I did have to use a spacer. I rolled the fender lip up as well. I had a later A body 8 1/4 in it. A P245 works out to 9.65" wide. Once I installed the spacers I had no rubbing issues, but then again I didn't have a floppy drag only suspension. I was set up more for handling.