correct offest/rims for 5 lug swap with sn95 axles

[Jaym14]

I'm getting close to finally throwing together all the parts I need for my 5 lug swap. I'm planning on using the sn95 axles and I know they are a bit longer. I'm wondering what offset I need on my rims to be able to run 275 et streets without clearance issues. I have a set of 94 cobra rims that someone donated to the project but I'm not sure if I'll have clearance issues with them.

 

[Jaym14]

I know some of you 5 lug swap experts must have tackled this one before...

 

[Shaolin Crane]

I'm getting close to finally throwing together all the parts I need for my 5 lug swap. I'm planning on using the sn95 axles and I know they are a bit longer. I'm wondering what offset I need on my rims to be able to run 275 et streets without clearance issues. I have a set of 94 cobra rims that someone donated to the project but I'm not sure if I'll have clearance issues with them.

i run hoosier R6 road race tires on 6.42" backspaced rims and they fit fine tire size was 275/40zr17

 

[stang&2Birds]

You want an M179 rim, or equivalent.
From:
Ford Racing Performance Parts [M-1007-M179*]

• Fits 1994-2004
• 5-lug, 4.5" bolt circle
• 5.98" backspacing
• 24mm offset
• 17" x 9" wide
• Same as M-1007-R58 except 6.42” backspacing

• M-1007-M179*
• Fits 1979-93 Mustang with M-2300-K brake kit, front use M-1007-R58
• 5-lug, 4.50” bolt circle
• Same as M-1007-R58 except 6.42” backspacing (36mm offset)
• Includes center cap M-1096-M
• Will not fit 4-lug applications

You can find often find M179 rims in the classifieds here and on the other site.

Also:
Mustang Saleen Wheels Saleen Cobra Wheels! Saleen wheels,Saleen rims,Saleen Cobra Wheels
Has sliver and chrome "M179" style rims:

Silver Saleen Style, 17 inch
17x9 inch , 5x4.5" 36mm
Silver Wheels ; Fits 2005-2007 Ford Mustang
Brand New Silver Wheels ; Center caps are included. ; In Stock
SAL-796536S ; $495/set

Chrome Saleen Style, 17 inch
17x9 inch , 5x4.5" 36mm
Chrome Wheels ;Fits 2005-2007 Ford Mustang
Brand New Chrome Wheels ; Center caps are included.; In Stock
SAL-796536C ; $699/set

So, it would seem that there will be a source of the 17x9 36mm offset rims "Cobra R style" rims for the future! Also, they have a number of options for widths and offsets.

Note: The exact tire that you use will make a huge difference! And, tire specs change over the years (even for the same model!). So, be careful about advice. And, of course, different year Stangs had different amounts of clearance in the front & back fenders.

 

[stang&2Birds]

I'm wondering what offset I need on my rims to be able to run 275 et streets without clearance issues.

BTW: You'll likely need to roll the fenders for 275s.

 

[Shaolin Crane]

yup, the m179 are the ones i have, you dont NEED to roll the fenders but you are going to want to, there is a set of m179's on CC right now

 

[Jaym14]

thanks for the reply... so basically I should be looking for a 9 inch rim with at least 36mm Backspace?

 

[Shakerhood]

You want an M179 rim, or equivalent.
From:
Ford Racing Performance Parts [M-1007-M179*]

• Fits 1994-2004
• 5-lug, 4.5" bolt circle
• 5.98" backspacing
• 24mm offset
• 17" x 9" wide
• Same as M-1007-R58 except 6.42” backspacing

• M-1007-M179*
• Fits 1979-93 Mustang with M-2300-K brake kit, front use M-1007-R58
• 5-lug, 4.50” bolt circle
• Same as M-1007-R58 except 6.42” backspacing (36mm offset)
• Includes center cap M-1096-M
• Will not fit 4-lug applications

You can find often find M179 rims in the classifieds here and on the other site.





Note: The exact tire that you use will make a huge difference! And, tire specs change over the years (even for the same model!). So, be careful about advice. And, of course, different year Stangs had different amounts of clearance in the front & back fenders.

I know that 6.42" of Backspace for a 9" Wheel on the Rear is what Ford calls for. The Saleen Rim you listed says 36mm offset, if my math is right that is roughly 1.4-1.5" so how does that equal 6.42" of backspace?

 

[stang&2Birds]

yup, the m179 are the ones i have, you dont NEED to roll the fenders but you are going to want to, there is a set of m179's on CC right now

I repeat:

Note: The exact tire that you use will make a huge difference! And, tire specs change over the years (even for the same model!). So, be careful about advice. And, of course, different year Stangs had different amounts of clearance in the front & back fenders.

As I mentioned, it seems like tire manufactures like to screw around with tire specs year to year.

Also, don't forget, the factory tolerances add up! And, especially with the rear, many Stangs have their axles offset because of worn/damaged torque boxes, bushings, etc. Also, even from the factory, the front and back fenders often had different horizontal clearances to the tire.

IMHO, when you're dealing with tire/fender tolerances, there is no such thing as saying "I can guarantee that setup XYZ" will work on your car. Well, unless you're talking 100% stock with OEM tires that were made in 1993.


Again, that all has to due to real world tolerances, especially in the POS factory front fender alignment. From my car pictures and the front hood, you can see a good example of the the POS factory tolerances. In those pictures, the hood and fender were never before off the car. (I replaced the engine this winter, so the hood came off for the first time). I know te history of my Stang from day 1. I was there when it was ordered, I drove my best friend to pick it it, and I often drove him back to the dealer to pick up his car after any service.


BTW: The mouse wheel scroll with Firefox 3.6a (alpha developer release) is driving me up a wall!!!!!!!!

 

[stang&2Birds]

I know that 6.42" of Backspace for a 9" Wheel on the Rear is what Ford calls for. The Saleen Rim you listed says 36mm offset, if my math is right that is roughly 1.4-1.5" so how does that equal 6.42" of backspace?

Note: *I* added the 36mm offset to the specs. That may be wrong. But, I'm pretty sure that it's correct.


From the Ford spec, for the M-1007-R58

• Fits 1994-2004
• 5-lug, 4.5" bolt circle
• 5.98" backspacing
• 24mm offset
• 17" x 9" wide
• Includes center cap
• Will clear M-2300-K disc brakes
• Same wheel used on 1995 SVT Mustang Cobra “R”

and
6.42" - 5.98" = 0.44"
and
0.44" = ~11mm

So,
24mm + 11mm offset = ~35mm

Add in round off errors, and you get that a backspacing of 6.42" = 36mm offset.

 

[Shaolin Crane]

ok so im not exactly certain he will, but the R6's are the widest 275's ive seen yet same as some brands 285's, so if those fit on my rears then im sure another brand of 275's will fit fine

 

[stang&2Birds]

ok so im not exactly certain he will, but the R6's are the widest 275's ive seen yet same as some brands 285's, so if those fit on my rears then im sure another brand of 275's will fit fine

Mine don't. And, IMHO, most do not!

Plus, are your rear fenders lips100% stock??? Can the rear of your car go 100% full jounce without the fender lips scraping the tire? If so, how do you know?

And, many other people also have problems with 275's fitting in the rear. As far as I've seen, most people that have 275's in the rear with sn95 rear axles end up rolling the rear fenders. And, that's includes people like me that run the M179s.

In fact, my 245's do not "fit" on my D178 rims in the rear. In the rear there is a very slight interference between the tire and fender at ~3/4 jounce. But, I have an '86. And, the fenders (front and rear) aren't as wide. Also, my 245's have a very wide contact patch (the reason I got them). And, hence, they also have a wider than typical sidewall width for a 245.

On the other hand, a "Pep Boys" special 245/45/17 would likely fit fine without any rubbing at all. I know that, by the specs, some 245/45/17's on tirerack should ft my car fine.

But, I don't want a cheap tire, or a "ricer tire" (a thin tire that is marked/listed as a wider tire than is typical for a particular size).

GEEZ! Must everything become an argument????
WTF is this becoming the corral? They couldn't even have a thread about an '86 block without it getting locked. What else is new? And, IMHO, 99% of the info given in that thread was wrong/BS/misleading! I didn't even bother to reply. I know that site and how futile it often is to reply to threads like that.

Have fun people. I said my piece. I may or may not be right. Your choice.

 

[Shaolin Crane]

Mine don't. And, IMHO, most do not!

Plus, are your rear fenders lips100% stock??? Can the rear of your car go 100% full jounce without the fender lips scraping the tire? If so, how do you know?

And, many other people also have problems with 275's fitting in the rear. As far as I've seen, most people that have 275's in the rear with sn95 rear axles end up rolling the rear fenders. And, that's includes people like me that run the M179s.

In fact, my 245's do not "fit" on my D178 rims in the rear. In the rear there is a very slight interference between the tire and fender at ~3/4 jounce. But, I have an '86. And, the fenders (front and rear) aren't as wide. Also, my 245's have a very wide contact patch (the reason I got them). And, hence, they also have a wider than typical sidewall width for a 245.

On the other hand, a "Pep Boys" special 245/45/17 would likely fit fine without any rubbing at all. I know that, by the specs, some 245/45/17's on tirerack should ft my car fine.

But, I don't want a cheap tire, or a "ricer tire" (a thin tire that is marked/listed as a wider tire than is typical for a particular size).

GEEZ! Must everything become an argument????
WTF is this becoming the corral? They couldn't even have a thread about an '86 block without it getting locked. What else is new? And, IMHO, 99% of the info given in that thread was wrong/BS/misleading! I didn't even bother to reply. I know that site and how futile it often is to reply to threads like that.

Have fun people. I said my piece. I may or may not be right. Your choice.

wow seems i've rubbed you the wrong way, i didnt mean to argue i was just stating my experiences so far, no my fenders arent rolled at all, but yes they will be rolled soon just in case, and i have a PHB so that helps too, i aplogize if it seems like i was arguing

 

[Kumm3]

More info:

Im running OEM 03 Cobra wheels on an 94-98 spec rear axle, the specs on the wheels are 26mm offset, with a 6.12" backspace. I did need to roll the rear fenders with the 275 series tire. It wasn't much clearance needed, but it was enough to cut up the sidewall a little, most people dont even notice it on the tires though.

 

[LarsD]

More info:

Im running OEM 03 Cobra wheels on an 94-98 spec rear axle, the specs on the wheels are 26mm offset, with a 6.12" backspace. I did need to roll the rear fenders with the 275 series tire. It wasn't much clearance needed, but it was enough to cut up the sidewall a little, most people dont even notice it on the tires though.

Have any pics? Car looks good from your sig.

 

[Jaym14]

does anyone know the specs of those old 94 cobra rims that a friend donated? If they are close enough I would rather roll the fenders than have to buy a new set of rims when I have a free set (in immaculate condition) sitting here. I'm currently running 275 50 R15's on weld draglites with my stock fox axles and they never hit.

 

[Kumm3]

does anyone know the specs of those old 94 cobra rims that a friend donated? If they are close enough I would rather roll the fenders than have to buy a new set of rims when I have a free set (in immaculate condition) sitting here. I'm currently running 275 50 R15's on weld draglites with my stock fox axles and they never hit.

IIRC, you should have a 5.72" backspace.

Not 100% sure on the offset, but you will not have any issues with them rubbing the fenders, they will be tucked in enough to clear. Keep in mind, those are only 8" wide wheels, so they are easier to package on the back of a fox with SN95 rear.

 

[Kumm3]

Have any pics? Car looks good from your sig.

Here are the most recent, forgive the lack of paint. All the extra cash is going to pay for a wedding, so the car is a little on the back burner these days.

 

[Jaym14]

Thanks for all of your replies. I definitely have a better sense of what will fit and what wont.

 

[LarsD]

Here are the most recent, forgive the lack of paint. All the extra cash is going to pay for a wedding, so the car is a little on the back burner these days.

Thats cool, my Dart is three colors too. Car looks great with the Cobra's. I see you have Aerocatches also. I just got a set. Have to work up the nerve to cut my CF hood though.