Fox T-Bird/Cougar Forums

Thanks to all of your help, I successfully completed my 11" brake upgrade over the weekend, and I love it.  While I was at it, I put a set of SN95 springs on the front with adjustable caster/camber plates, and it finally sits at a reasonable level!  One side effect, however, is that now under hard braking or a bump in the road, the tires rub on the fender lips, as I have the cobra-r rims that stick out of the fenders just a bit (this has always annoyed me).  I'll post some pics once it stops raining.

My mechanic, who is well versed in FoMoCo, suggested that I try swapping to a Fox Mustang front lower control arm, which is slightly shorter, and thus would bring in the tire. I have done some searches on this board, but haven't found much information about if this would work or not.  Has anyone tried this, and if so, what were your results?

Thanks!

It would pull the wheel in 3/4" at the bottom, but you will lose turning radius and mess up the alignment. You do have caster camber plates so you might be able to get it back into alignment.

I'd just get rims that fit.

Thanks, Haystack. New rims are definitely an option, but I love my rims - I'll have to see if I can find a 4-lug cobra r with different backspacing.

 What do you mean by losing turning radius?  It seems like our cars' turning radius can't get any worse!  Do you mean that these control arms are built with more limited turning radius, or are there clearance/rubbing issues associated with using the mustang control arms on our cars?

Here is a pic of my TC with Fox Mustang arms and Fox Mustang K, TC springs,17x 8" 225/55 front, 17x9" 255/50 rear Cobra R replicas from OE Wheels and MM CC plates....I've got about 1.5" clearance top of tire to fender lip.... I originally had the TC arms and hated how the wheels stuck out.
(http://www.foxtbirdcougarforums.com/attachment.php?attachmentid=38247&d=1490549286)

Sorry for the large picture.... Uploaded from my phone.
John

Thanks for the pic and description, John!  This is much more the look I am going for.  A  couple of questions for you;
Do you have any issues with the tires rubbing on the inside fender well when turning?
What are the advantages of a Fox Mustang K member - would I be able to achieve the same results by using my stock k-member by only switching out the Fox Mustang k-member?
Here's how mine looks currently;

Lol.....thats exactly how mine used to sit.

No scrubbing whatsoever. It did scrub with the longer arms. As for the Mustang K......No real advantage other than being able to modify height easier and availability of aftermarket mounts. It also gave me a little assurance everything works correctly together...Even if it only I'm my mind. I also did it in hope that if I ever go 5 lug.....My wheels will still sit in the fender wells. Tires appropriately sized for the car are getting harder to find so I see myself going 5lug and larger wheels to compensate.

 I really don't know what kind of results you will have just swapping arms but It will be better than what you have now. The offset and backspace on the wheels should set the tire closer to proper location.

John

There is a 10% increase is turning radius between 87- 88 cars and the 83- 86. Largely due to the shorter fox stang length arms. Every time I jump in my 86 after driving my 88 I misjudged parking spots, forgetting it doesn't turn as sharp.

Great tips!  Not digging the turning radius disadvantage, but I think I can live with that more than the tires rubbing on the fenders all the time.  I'm really surprised that this topic doesn't come up more on the message boards - unless I'm just searching wrong.  I think I'm going to move forward with swapping to the fox mustang arms and see what happens - I'll keep you posted.

It will suck the bottom of the tires in and create some positive camber.  With the CC plate you should be able to compensate for it and get the tires sucked under the sheet metal like you are wanting.  The only adverse affect is you are moving the inner lip of the rim inward which when turning the car will put it closer to the subframe.  In some cases the rim will come into contact with the control arm or the tire will hit the subframe and you will need steering limiters.

Are the wheels aftermarket or OEM?

Regardless of OEM or aftermarket........The wheels likely have an offset for a Fox Mustang and not the rediculous front wheel drive offset they used for the T-bird.  I would have to look it up but in theory the Mustang offset pushes the wheel outward......A shorter arm will pull it back in very close to original stock position. The only place you need to check for contact issues will be the top lip of the wheel to the strut.. Like you said ...... CC plates will take care of the alignment and if aligned properly you won't have contact.

John

Appreciate the info but I still would like to know if they are OEM or aftermarket.

I have the OEM (Ford Racing brand) 4-lug Cobra R's (17" x 8") with 245/45/R17's (see pics).  The backspacing (offset?) is huge on these wheels - one of the reasons they stick out so far from the front fender.  The catalog says that the backspace is 5.15", with a 15mm offset.  It seems like there's 3-4 inches between the rim and the brake caliper.  Really hope I don't need those steering limiters.  Seems as though every mod  I do requires an additional 5 mods to make it work - feels like I'm going to end up with a Mustang when it's all said and done!  lol - this all started with wanting better brakes...

I'm now really glad I sprang for the CC plates, everyone is right about them being a must-have when you start messing with springs/control arms, etc.  After just changing to the mustang spindles my alignment was crazy bad.  I have to say though, all this work seems worth it - even though I'm not well aligned yet, the handling with struts and springs from a SN95 Mustang do wonders for these cars - literally feels like a different car!  (Doesn't help that one of my struts was COMPLETELY dead.)

When I had 235/60's on mustang 10 holes on my 87 bird the tire was less then a finger width from the strut. The 275/60's would rub really hard on the strut. This was all stock junk though. I beleive the 11" spindle pushes stuff out a hair.

So lets get some base wheel measurements so we can start talking geometry.  The factory 15" x 7" 10 holes for the Birds and Cougars had a 5" backspacing with a 25mm offset and the 87-88 16"x 7" TC Snowflakes had a 5.25" backspace with a 31.7mm offset. Now I have no idea what the stock size tire was on the ten holes but I do know that the Snowflakes came factor with 225/60/16's Goodyear VR Gatorbacks.  Also wanted to clear up that there were only three years of the Cobra R and they were in 93, 95, and 2000 of which the OP's wheels are styled after the 1995 Cobra R.

The whole exercise here is to see where the current wheel/tire combo is in relation to the factory wheel/tire combo for clearance reasons.  Being that the OP changed to the 11" front brake setup and the TC's had this setup we will use the Snowflake wheel the associated stock tire that went with it to compare to the OP's current setup.

If you do a side by side comparison of the Snowflake wheel/tire combo to the OP's "1995 Cobra R" replica wheel/tire combo to the Snowflake wheels you will see that the difference are as follows:

1995 Cobra R Replica
Tire Height - 25.7"
BackSpace - 5.1"
Offset - 15mm (0.6")
Width of Tire at Sidewalls - 9.6"

Snowflake
Tire Height - 26.6"
BackSpace - 5.3"
Offset - 33mm (1.3")
Width of Tire at Sidewalls - 8.9"

I got all of this by inputting the known data at this site - https://www.rimsntires.com/specspro.jsp

So what this gets you is that from where the back of the wheel hub mounts to the rotor face to the inside wall of the tire the Snowflake combo measures (Offset + 1/2*Width of Tire at Sidewalls) 5.75".  The 1995 Cobra R Replica combo measures 5.4".  With that you can see that the inside wall of the 1995 Cobra R Replica combo tire is 0.35" further away from the strut than the stock Snowflake combo.

Now lets think geometry and say that the control arm is parallel to the ground and the strut is the hypotenuse thus giving us a 90 degree triangle.  Lets further assume that where the tire would contact the strut is about in the middle.  Quick math tells me that if I install the Fox control arm i.e. shorten the control arm 0.75" that the inside wall of the tire will move in about half that distance or a little more (draw a triangle with the strut as the hypotenuse and the control arm as the bottom leg and you will see it).  So let's call it 0.5" just to be on the safe side.

With that the actual distance the inside wall of the tire will move toward the strut is about 0.15" or about 5/32".

So to the OP, if you currently have 3/8" clearance between the inside wall of your tire to the strut my guess is that it will clear if a Fox lower control arm is installed.  I would definitely put pencil to paper and take a few measurements before I did it but my confidence level is really high that it will work.

I did this same upgrade last year. Braking greatly improved, but I'm experiencing the same issue as the O.P..  Is it possible to find a wheel that the offset is better? Just curious as I'm thinking of changing wheels. I currently have 17×8 Saleen SC replicas(can't remember offset at the moment)

Holy smokes, my head hurts after Aerocoupe's geometry lesson!  ...although I have to admit that science is probably better than my method of buying parts and hoping it fits.  I went out and checked, and as I can pretty easily fit my hand between the tire and strut, I would say I have at least an inch gap.  If your measurements are correct, that means I should be golden!  I didn't even think about the strut being an issue, as the strut, spindle and control arm are all off of a mustang, I guess I just figured a mustang rim would fit with all that - although the one thing I didn't consider is the angle of the strut, as the cougar strut towers may be in a different spot than the mustang - does anyone know if that's the case?

If you have an inch between the tire and the strut you should be good to go. I didn't get into the weeds on the math but I was trying to get everyone to think about how one change impacts multiple things within the geometry of the suspension.

Remember when you install the lower control arms to torque the bolts with the suspension loaded and the car level.

The stock tire size for the 10-holes was 225/60-15.

Many years ago I purchased a OE set of 10-holes from a 1986 Mercury Capri 5.0L (same as a Mustang GT) that a friend of mine had bought new. He immediately put a set of aftermarket wheels on it and had these stored in his garage.

The Mustang/Capri 10-hole wheels measured exactly the same as my original XR-7 10-hole wheels.

Over the years I have acspoogeulated and measured various wheels and started a spreadsheet of them.

I have three different casting numbers on my two sets of ten holes. I wonder if they are all the same.

Just wanted to post an update on the control arm swap project.  It's all done now, and it's one of the few projects that came out just as I had imagined!  It brought the front wheels and tires into the fenders nicely, and completely eliminated the fender rub I was experiencing over bumps and heavy braking.  As everyone else was saying, this project can't be done without the Caster/Camber plates - thank goodness Maximum Motorsports makes them for our cars!  Along with the new SN95 struts and springs, the car handles much better now, as well.  Highly recommended!

Looks good.. Did you swap in 87-93 GT control arms? In having similar issues after my swap, so I may try this as well. Have you noticed any issues yet? Great looking car by the way.... Ray.

Get a rack from a salvage yard off a Fox Mustang and use those tubes or someone on here might have a junker laying on the shop floor they can pull them off of.

I have reman units in both cars and have only had an issue once.

Looks good!!! Thanks for the update.

John

Thanks, guys!  Yes, Ray, the control arms were off a '90 Mustang GT - I believe any of the V8 Mustang control arms will fit from those years and get the same result.  I purchased used control arms and replaced the bushings and ball joints - if I had it to do over again, I would have purchased new control arms that already have these installed, as the bushings and ball joints were a MAJOR PAIN to install into the control arms.  I have noticed NO issues thus far.  I was worried that there would be issues with turning radius/tire rub on the inner fender, but I haven't experienced either!  The only thing that you could possibly consider an issue, would be that the alignment guy wasn't able to get the caster/camber exactly back to stock specs, even with the caster/camber plates.  (The wheels are more straight up/down than the stock camber.) That said, it's pretty close, and the car drives straight and feels like it handles better than ever (it helps that I just got new springs and struts). My wife also drove it to work the other day with no complaints.

P.S. - I believe there are some posts around here about the fact that SN95 control arms may also work on our cars.  I believe the advantage to the SN95 control arms are that they give extra clearance for larger brakes, and they have a better ball joint design.  I didn't discover this until I had already done the 11" brake conversion from the stock 10" front brakes - otherwise I may have gone that route.

The SN95 control arm may be narrower to clear large diameter wheels when turning lock to lock but I haven't seen anything with regards to larger brakes and I really don't see how they would affect that.  The ball joint design in them is a low friction unit and it is much shorter than the Fox ball joint so you cannot use this style of ball joint with the Fox spindle.

What happens when the guys are converting to the SN95 five lug brake design in a Fox car is an SN95 ball joint is pressed into the Fox Control arm.  So with that a Fox ball joint will press into an SN95 control arm and it has been done multiple times.

I used 2003-04 Cobra control arms, I had to machine the Fox 11" spindle cuz I wanted to stick with 4-lug front/rear (so 20th rims could be bolted on if needed.) I thought I posted pictures of me machining the spindles somewhere.

Found it:

I have 2001 Bullitt springs (or is it 03/04 Mach 1?) front and rear - lowered the car nicely and give adequate handling without a sway bar (never put back on - drag racing it.) Note the rears are wicked short - I have adjustable spring perches.

The control arms are great. I used American Racing Rebel wheels which are discontinued.

Kewlcoug, have you noticed any problems so far with this swap? After some drive time...

Do you remember how much you machined off? I'm pretty sure a local machine shop could do that if one doesn't have a lathe at home.

Who doesn't have a lathe at home? Just kidding. I have one, but I never really got it all setup.

Me. I don't have room :hick:

Hmmm, I don't recall, but my goal was to have enough threads above the locknut to give me a comfort level - i.e. the nut won't be able to loosen on it's own! Did this 10 years ago (2007) but I did dospoogeent it:

Looks like you ended up machining off about 1/8"?

I've still got the 10" brakes up front on my car with those same 03-04 Cobra front arms FRPP used to sell. I didn't have to do any machining to get the nylock nut to engage with the 10" spindles. Got thread above the nylock. That area must be slightly thinner on the 10" spindles. The arms have been in for almost 10 years now. I painted a line across the face of the nylock nut and onto the spindle when I installed the arms. The nut hasn't moved in all that time.

Being I'm planning on (probably in the spring) going to 11" front brakes I'll be having the local machine shop take a bit off the ball joint nut pad on the 11" spindle.

Why not just install Fox ball joints into the SN95 control arm and then you don't have to machine anything??

Because the arms come with those fancy low friction ball joints you don't have to grease. I'd rather keep those ball joints than use MOOG pieces.

That was my reasoning too. Although having a milling machine in my garage was in my favor as well. :mullet:

Quick Question, not trying to hijack the thread here. I'm going to be performing a 5.0L swap on my TC. As far as Tube K members go what's the best way to go? I see some guys go SN95 tube K's with SN95 arms and spindles, anyone have any input?

Maximum Motorsports Foxbody K member with sn95 arms

So just use these and later down the road when you want to convert to 5 lug and brakes that don't suck you can pop the Fox spindle off and put the SN95 spindle on.

http://www.maximummotorsports.com/Ford-OEM-Low-Friction-ball-Joint-1979-2004-Mustang-P1465.aspx

I haven't checked this thread in awhile, and a few months ago someone asked how this swap is going a few months in.  I honestly haven't driven the car as much as I would like, but it seems to be holding up nicely.  I'm still happy with the handling and still don't have any tire rub issues.  The only thing that I wish would have gone better is the camber adjustments, as I mentioned earlier that I couldn't get it quite back to stock specs - that said, it's workable and so far hasn't made my tires wear badly or caused any significant handling issues.

Looks like the low friction joint isn't at MM anymore.  Just to clarify that part number F4ZZ-3050-B will fit the 11" Fox mustang GT spindle without any machining or issues of nut backoff.  Thanks guys.

When I did the Fox control arm/Sn95 spindle swap on my 87 TC , I also elongated the strut tower holes in addition to using the MM plates to allow for more neg camber range.

The strut towers arent exactly made out of tissue paper so it does take some time and a good carbide burr, a die grinder, and most importantly some safety glasses.  A shop vac and some primer and  paint should also be part of the plan. But the results were worth it.

Wanted to post where you can get the ball joints for the control arms.

https://www.tascaparts.com/oem-parts/ford-suspension-ball-joint-f4zz3050b

Not sure who makes them anymore as the last source was Lemfoerder under part number W0133-1627287 which is who MM was getting them from.  My guess is the ones from Ford will be the best source as the original maker was TRW who sold to Moog who sold the ball joint design to Lemfoerder who doesn't appear to make them or at least not advertise it to the general public.