5 lug swap/IRS swap project question

So I'm in the middle of accumlating all the parts needed for a 5 lug swap and can't decide what front spindles will work best with the setup I want to run. I have a '03 Cobra IRS setup for the rear so I decided to go with 99-04 spindles and '03 Cobra brakes/rotors. I realize I'll have to buy new rims with custom offsets for the setup I've chosen but already have the Foose Nitrous in mind, they have pretty extreme offsets/backspacing that I think will work.

I was just about to order a brake proportioning valve, eliminator kit, and the '93 Cobra master cylinder adapter kit from Maximum Motorsports when I started to read:

"Warning: 1996-04 spindles & Stock pre-1996 K-members. Do not install a 1996-04 spindle on a 1979-93 or 1994-95 Mustang fitted with a stock-geometry k-member!"

in the tech articles. It went on to say that it is "impossible to correct the bumpsteer" created by using the 1996-04 spindle because "The lower steering arm is far too low for the steering rack location of any 1979-95 Mustang, and radically changes the steering geometry."

Now I'm confused because I had read the same exact thing about the SN95 94-95 spindles, that they were poorly designed and had terrible bump steer on Foxes and that is why I bought the 99-04 setups.

I was hoping somebody could clear this up for me.

Just in case you need to know there are the parts I have so far:

1991 Ford Mustang GT Convertible.
99-04 GT spindles rotors and calipers.
'03 Cobra calipers, rotors, SS lines.
'03 complete Cobra IRS.
1993 Cobra Master cylinder and brake booster.
2000 GT rims and tires.

The rest is on hold until I figure out what to do about the spindles. I already bought the 99-04 brake assemly, then decided to match the rear cobra with front cobra brakes. I'd hate to have to try and sell the front assemblies and find SN95's now.

Sorry about this being so long but I wanted to be sure to include everything.

Thanks,
Joe

93 LX said:

The 96 and up cause the wheels to stick WAY out and you must do something with the tie rod ends so you can align it.

IRS INTO FOX BODY

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I'm aware that the 96+ spindles push the track width out (I was trying to keep the track width the same in the front and rear, '03 cobra specs) that's why I am using wheels with sufficient backspacing to offset the wheels and bring them back in the wheel well. The wheels won't stick out if you use the correct backspacing. Tie rod ends are loosened and tightened to adjust alignment as well as caster/camber plates.

My question was about which spindle should be used to avoid bumpsteer issues. SN95 or 99-04? Or do they both have issues with bumpsteer?

Is there anyone out there running 99-04 GT spindles on a Fox mustang that can shed some light on how the car handles?

Ha, weird, I'm actually on Steeda's website right now looking at the bump steer kits.

bgjohnson said:

I know people using them with no problem, I know other people using them that a 5 lug wheel rubbed on the fender when lowered.

I have some lying around so I will try them first, if they don't work, i will just sell them on ebay and get some sn-95 spindles.

I think it works like this. SN-95 spindles put the track width 4-6mm wider in the front, and the 96+ put it 12mm wider. So really your creating less than a half inch on either side outward.

Which isn't a huge deal, but in some cases might cause minor clearence issues.

Click to expand...

Yeah, I think I'm just gonna throw the 99+ spindle on there and see what happens. It the don't work I'll try caster/camber plates and if they still don't work I'll go for SN95's.

Let me know how it goes for you bgjohnson.