275/50R15's

275/50R15's and 9 inch rear

Would it be possible to fit soem 275/50R15's on the back of my Cobra? I'm planning on relocating the springs inward like Robert Szewczyk did and trim the fender lips as much as possible. I want to go with Weld Pro Star XP's, should I go with 15 x 8" with a 3 1/2" backspacing, or 15 x 9" with a 5 1/2" backspacing?

Another question: I will be swapping a 9" rear under the Cobra when I do this, and I've heard a rear end from a 65/66 Mustang is the right width, the perches just need to be moved inward. Is this true? I've also heard a rear end from a 66-77 Bronco will work, too, it's just 1/2" wider (which could help me if I'm going with 5 1/2" backspacing), needs spring under perches, and the axles need to be swapped with ones with a 5 x 4 1/2" bolt pattern. Again, is this true? A big swap meet is coming in 2 months, and I will be on the lookout, and I have a lot of connections with Early Bronco guys.
 
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1badII said:
Would it be possible to fit soem 275/50R15's on the back of my Cobra? I'm planning on relocating the springs inward like Robert Szewczyk did and trim the fender lips as much as possible. I want to go with Weld Pro Star XP's, should I go with 15 x 8" with a 3 1/2" backspacing, or 15 x 9" with a 5 1/2" backspacing?

My first impression would be maybe. I just did some measuring last night on the 78, to see what kind of tire I can stuff under there with new rims. Even if you move the spring in, the wheelwell still sits where the spring was. If you rolled the lip on the fender, that will give you some room. I THINK I can run the M&H DOT 275/50-15, going by their listed specs. It will JUST fit with a rolled lip from my calculations. But a regular radial street tire is going to be more square, and may not fit. You'd have to get tread and cross section dimentions from the manufacturer of the tire you are looking at.
 
Oops, I forgot to say what tires I want. I want to run Nitto 555 Drag Radials for the street, and Mickey Thompson 26 x 10.5" ET Streets for the strip. I haven't gotten under there and looked, but would I be able to hammer the inner wheel well in some?
 
on my car i have the lowering blocks from racer walsh and i was wondering what is the widest wheel i could use and with what tire. i would'nt mind massageing the wheel well lips.right now i have on there 14x7 w/245-60-14 and they will rub when the rear is under compression.i want to put on the weld drag lites in 15x7(3.5 or 4.5 back spacing) or the 15x8(4.5 or 5.5 back spacing). could i put 245-60x15 or maybe 255-60x15? or maybe run a 70's series tire? also want to run the old style slapper bars with it.
 
manny said:
on my car i have the lowering blocks from racer walsh and i was wondering what is the widest wheel i could use and with what tire. i would'nt mind massageing the wheel well lips.right now i have on there 14x7 w/245-60-14 and they will rub when the rear is under compression.i want to put on the weld drag lites in 15x7(3.5 or 4.5 back spacing) or the 15x8(4.5 or 5.5 back spacing). could i put 245-60x15 or maybe 255-60x15? or maybe run a 70's series tire? also want to run the old style slapper bars with it.

Manny, check out my ebay auction for the rear wheels I've got for sale:

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2457618091&category=43955

Those are 15x7 Draglites, with M&H DOT tires, that are equal in size to 245/60-15s. You can see from the two pics just how they fit in the car. Hope this helps :nice: .
 
CobraIILover said:
Even if you move the spring in, the wheelwell still sits where the spring was. If you rolled the lip on the fender, that will give you some room.
So did Robert Szewczyk just relocate his springs inward to clear the ladder bar setup? It didn't give him any more clearance? Does anyone have his email address? I'd like to ask him about that.
 
1badII said:
So did Robert Szewczyk just relocate his springs inward to clear the ladder bar setup? It didn't give him any more clearance? Does anyone have his email address? I'd like to ask him about that.

I have no idea what Robert did on his car. But I can tell you that the subframe rail runs right along the edge of the inner fender. So if you wanted to move the inner fender in more, I'd think you'd also have to remove the stock subframe and put in new rails inboard more. That's just my opinion on the way the car is setup.
 
I just got under and looked, and it looks like I'll want to go with the 15 x 8's with the 3 1/2" backspacing. The body shop I'll be going to to fix the damage from when I was rear ended said they can flare the fender out some in addition to trimming the fender lip. I think I'm going to go with that. As far as relocating the springs, I see what you mean that they're about even with the wheel well. I think Robert just relocated his springs to make room for his ladder bar setup. When I get the tires on, I'll make a post with pics. Also, I contacted Calvert Racing about making some Caltracs for me, and they sent me a dimentions sheet to develop them. Hopefully, they'll put them into production.
About the 9" rear end, a rear from a 65/66 Mustang is the right width, right?
 
hey cobraII, the add says they are 15x6? are they 6" or 7" wide? where on long island? i'm from commack and still have relatives in hauppaque.would you sell them without the tires?glad to see some guys from NC, will be moving to charlotte within the next 6 months.we'll need to get together at some shows there and show just what a II can do :D
 
manny said:
hey cobraII, the add says they are 15x6? are they 6" or 7" wide? where on long island? i'm from commack and still have relatives in hauppaque.would you sell them without the tires?glad to see some guys from NC, will be moving to charlotte within the next 6 months.we'll need to get together at some shows there and show just what a II can do :D

Yes, they are 15x6 with a 3.5 backspace. They fit the stock setup perfect, as you can see from the pics. I'm about 10-15 minutes from Commack, over in Sound Beach. I would rather sell them as a set, but I will sell just the rims to you if the auction doesn't sell.
 
I am trying to hook up with a guy locally who is selling a pair of Weld Draglites 15x8 with 4.5" backspacing. They have 275 15 50's, BFG Drag radials mounted on them. If I can get a test fit I will report back.

I mounted an old 15x7 turbine (which I measured at 5" of backspacing) and it looked like it would be tight at the front side of the wheel well where the seat belt is mounted. I am thinking 4.5" might be just right.
 
HaveII said:
I am trying to hook up with a guy locally who is selling a pair of Weld Draglites 15x8 with 4.5" backspacing. They have 275 15 50's, BFG Drag radials mounted on them. If I can get a test fit I will report back.

I mounted an old 15x7 turbine (which I measured at 5" of backspacing) and it looked like it would be tight at the front side of the wheel well where the seat belt is mounted. I am thinking 4.5" might be just right.
That would be great!
 
I tried the wheels out last night (Weld 15x8 w/ 4.5" backspacing and 275/50/15 BFG drag radials). I will start by saying that the wheels looked great under the car, but the back spacing was too far back at 4.5" that I could not bolt them on. :bang: The tires were hitting leave springs as well as the inner wheel well in the front and needed atleast another 1" of clearance to go on with a tire this size (wide center section). With the right back spacing and work on the lip on the wheel wells the tire itself has hope.

To my knowledge the rear end (housing) it original to my car so that leaves me wondering how others have been able to use wheels with backspacing like this. Is everyone using spacers? I don't see how any more than 3.5" of backspacing could fit with a wide tire. I know Weld makes them, but I suspect it will be hard to find one to test fit (15x8 w/ 3.5" bs).