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Discussion Starter #1
Hi all,

Looking for some advice on improving my car´s stance. I just installed AR Torque Thrust IIs in 15 x 7" front (3.76 bs offset -6mm) and 15 x 8" in the back (4" backspace with 0 offset) which are the sizes recommended for my car in the American Racing site. I´ve seen these same wheels in other cars and they fit right, but in my car they are still bit outside the fenders, which I don´t like.

My tires are 215/60 15" BFG Advantage T/As.

On the front, the wheels are OK, near the edge of the fender but still inside the fender, I´m planning on dropping 1" through lowering springs only (or maybe the Shelby drop).

On the rear, the problem seems to be the disc brake conversion (I bought the car with 4 wheel disc brakes, don´t know what brand they are). The disc rotors have aprox. 2.5 to 3" hub and I currently have a lot of clearance from the calipers to the wheels.

I know its not the wheels because they have 0 offset and have seen them in many other cars and they do fit, so I´m thinking its the huge disc brake hub.

What do you think? Can anyone recommend a rear disc rotor with less offset? My target is to have my wheels/tires pushed about 1" inside the fender, so I can drop the car 1" afterwards. (I have rolled fenders)

Here are pics of the rear wheel and disc brake setup and of the car...

Its a bit dark, but check the disc hub behind the chrome wheel. The wheel has zero offset.


Current look of the car
 

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It's not the "offset" of the rotor that matters but rather the thickness of the rotor where it fits on the end of the axle. A brake drum is only about 1/8" thick or less where it fits on the axle flange but a brake rotor is probably at least 1/2" thick. If you don't take that extra rotor thickness into consideration when measuring for backspace you wind up with the problem you now have. The only solution at this point is new wheels with more backspace.
 

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Discussion Starter #4
Are there any disc brakes that don´t take up as much space? I´ve seen the kits on Summit and CJ Pony that definitely look like the rotors have a less pronounced hub.

My other alternative would be to go back to drum brakes I guess. I want these wheels, already bought them and I know they can fit because I´ve seen them (exact same size) in other cars.
 

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15 x 7" front (3.76 bs offset -6mm) - this can work in the front. 4.25 is better...but the wheels only come in that right?

15 x 8" in the back (4" backspace with 0 offset) - this can not work in the rear...ideal fit on an 8 inch wheel is 4.75 bs.

Unless you have a spacer wedged between your axles and your rotor the disc brake is not the problem. The rotor simply sandwiches between the wheel and the axle and the thinkness of the motor at that mount is what adds track width....and it isn't any different than a drum. The rotor hat is designed to have the braking surface sit back off the wheel so you have a larger choice of wheels that will fit over it. To move those wheels in so they are an inch inside your fender lip you would need to shorten your rear probably 1.5 inch per side
 

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When buying new wheels and you're unsure of the exact backspace that's needed to put the tire in the desired location it's always better to get a wheel with too much backspace because the tire/wheel can be moved outwards with relatively inexpensive spacers. Moving a tire/wheel with too little backspace inwards is an expensive proposition because your only option is to narrow the rear axle.
 

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Discussion Starter #7
Thanks! I actually checked the wheel specs and the rear ones have 4.5" backspace (the 15 x 8) not the 4" I mentioned. Its actually maybe 0.5" at most what I´d like to "push" them inside the fender wells, but if it can't´be done, I´ll just drop a little the car on the back a little less than what I wanted to avoid rubbing.

I also checked the AR site to see if they have these wheels with a different backspacing, but on the 15x8 size, the 4.5" backspacing is the most they offer.
 

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What tires are you running in the rear? A 15x8 4.5bs is a good fit generally and the rim itself should be well under the lip of the fender at those specs, tire bulge...that's a different story and why I wonder what size you have. If they are the 215 you have listed in the first post then I would suggest breaking out the tape measure and check the width on your rear and make sure someone didn't swap in a 67-70 width setup or maybe a versialle rear since that was a popular choice for a while to get disc brakes...and is slightly wider than a 65
 

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Discussion Starter #9
Thanks a lot for the input dodgestang, I´ll take more detailed pictures and take measures on the rear end as well.

The tires are 215/60 BF Goodrich Advantage T/A (they are the next tire step up from the typical Radial T/As in BFs line) on the 4 corners.

I´m suspecting the rear en might have been swapped at some point because, as you mention, the wheels should be fitting inside the fenders completely, and they are sticking out about 1/2" currently on one side (right hand side) and on the other are pretty much straight with the corner.

The front ones are fitting sufficiently inside the fenders, they just look fat because the car is way too tall.

I´ll post more pics later
 

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Discussion Starter #10
Ok here are more detailed pics of the wheels and tires in relation to the fender clearance, as well as some pics from under the car:

Rear Right wheel (the one that sticks out the most), from behind:


RR wheel from the front:


Rear Left wheel from behind:


Rear Left from inside:

 

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Discussion Starter #11
More pics from the front wheels:

Front Right:


Front right (taken from the top), barely sticks out,


Front left wheel:


I appreciate the input. In general the front ones are "in the limit" but I can drop the car 1" as I planned. The rear ones seem to be the problem.
 

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More pics of rear? Doesn't look like it has tapered tubes....did all 65/6 have tapered tubes or just 9 inch from that year? It looks to have the 65/6 shock plates though....
Distance from leaf springs is a mile away....my money is on 67-70 rear, you could also measure the BS on the 15x8 wheels you have in the rear...they might have actually sent you the wrong wheels
 

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This is not a stock v8 car rear (not an 8 or a 9 inch)....is that a 7.5 or an 8.8....if an 8.8 unless it was shortened....I believe those are wider than stock 65/6

 

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For completeness since I didn't get to it last night....

8.8 rears are generally 59.25 inches
65/6 mustang rears are 57.25 inches

Giving you 2 inches wider...or 1 inch on each side....which easily explains why a 15x8 wheel with 4.5 bs and a 215 tire is giving you such problems.
 

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Discussion Starter #15
I have to do some more research with my local club, but this car is a Mexican built car, which I understand came with a Dana 44 Rear End (not totally certain, but I know my 81 Fox Mustang has a Dana 44 rear end and probably this car has one too). I don't´know if it was 7.5 or 8.8,

At this point I´m also suspecting this is not the original rear end.

The car is an original V8, that I know because it was the only engine offered in Mexico (289 with the 2V carb)

I measured the BS on the wheels and they have a 4.5" backspace.
 

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Another member- neurotoxin- has a Mexican Mustang with a Dana rear axle. I'll bet that's what you have- a Dana 30 or 44.
 
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