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Discussion Starter #1
Trying to figure out what wheels and tires to buy and people keep referring to fox width vs. sn95 width. What's the difference.
Thanks,
Andy
 

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3/4" shorter. If you start with sn95 and replace with fox you will also need brake offset brackets (Richard Oben sells) - you can get axles from him as well.

 

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Originally posted by Captain Gourley:
Any drawbacks to the Fox?

What are folks using for IRS?
I think Coupe guys prefer the longer SN95 axles, other than that I think the kit is designed around Fox width axles and that makes wheel and tire selection simpler. No drawbacks that I can think of other than the actual donor type was 4 lug.

IRS axles are a completely different animal although the finished overall width is intended to duplicate a Fox width rear +/-.

Sean

edited to correct an ommission

[ March 16, 2007, 06:38 PM: Message edited by: canuck1 ]
 

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Cobra Padawan
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So you had to shorten the SN95 to make it fit to the frame and body width? I hear the words "pin drive" thrown around a lot when talking about SN95. What does that do, exactly?
 

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FFCobra Craftsman
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Capt. IRS is completely different (axles called half shafts) They start with T-bird rear end.

Pin drive refers to how the wheels are attached to the hub. Pin drive does not have lugs and lugnuts, but rather "pins" (kind of like short non threaded lugs that fit into holes in the back of the wheel) but do not go through the wheel. Then the spinner is put on. The spinner is the only thing that holds the wheel in place. I guess in some places, Pin drives are not techically legal, but the spinners thread on so they self tighten going forward, are usually knocked with a hammer, and most people drill a small hole in one of the spinner wings and tie a safety wire on it.

To use pin drive on cars, you have an adapter that is screwed onto the lugs that holds the pins. The wheel is then put on the pins, over the adapter and then the spinner is put on.
 

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Originally posted by Captain Gourley:
So you had to shorten the SN95 to make it fit to the frame and body width?
Not necessarily, although some do in order to get more 'dish' in the wheel. There are a few wheel and tire combinations that will work OK without narrowing or changing axles, but you usually have to make some compromises to do it. Limited dish in the wheel itself, limited tire size (315's are a real challenge although some have managed it), and limited wheel choices are some of the reasons why most choose to swap for aftermarket 5-lug Fox width axles.

Sorry, but I don't know enough about pin-drive applications to be much help with that.

Sean
 

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There are 3 widths:
Pin width- narrowest, can use 5 lug vice knock offs

Fox width- middle of the three

SN95 width- widest of the three
 

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Originally posted by Stinson Pilot:
...SN95 width- widest of the three
I guess you could add that SN95 refers to both 94-98 era Mustangs (3/4" per side wider than Fox width) and 99-up which is wider still. While I think the early SN95 style can be converted to Fox width by swapping axles and caliper/axle brackets, the later models cannot and require narrowing or a custom fit wheel.

Sean
 

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Discussion Starter #14
Thanks for the replies. My axles are already installed and the rear end assembly is under the car and bolted in. Is there any way to tell what axles I have just by looking?
BTW, I got the whole assembly from Forte's.

Thanks,
Andy
 

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FFCobra Craftsman
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You probably have Fox width but to cheack just run a tape measure from one wheel mount surface to the other.It will be slightly off cause it will bend a bit but close enough to tell which you have. I can't remember the numbers so go to the FFR website,wheels section,and click on the details for several wheels.They give the dimensions of the axle there.Good luck
 

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Going nowhere fast.
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Originally posted by KC Wildcat:
Capt. IRS is completely different (axles called half shafts) They start with T-bird rear end.
True, completely different setup but the width is the same as SN95 and uses the same wheel offset.

Mike
 

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I'm fairly certain on these numbers (because I've measured them both in my garage):

94-98 SN95 = 61" +/- 1/4"

Fox = 59 1/4" +/- 1/4"

measured from wheel mounting surface to wheel mounting surface. In other words make sure the discs or drums are mounted to ensure the correct measurement. There seems to be some variation in manufacturing tolerances from the factory since we measured both a 1979 Fox rear and a 1993 Fox rear one was just under 59 1/4" and the other was just under 59 1/2". I only measured one (early) SN95 rear (my own) and it was 61".

I think the confusion when discussing the thunder-chicken rears is one model (the turbo coupe) is SN95 width solid axle whereas the super coupe is IRS which is adapted for the kit (FFR supplies the axles or half-shafts) to come in near Fox width. I have been told many are actually just shy of this width but rear aligment could effect this measurement with IRS.

Sean
 
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