Gaining track width for 93 cobra wheels

[85GT-79FJ40]

I bought some real 93 cobra wheels a week or so ago for my 85. I already have a turbo coupe rear axle in my car so the track width is perfect out back for the wheels. Up front i'm also swapping to 87-up brakes. I was intending on just using cobra rotors up front to get the extra 3/4" per side track width. But these rotors are a little tougher to find and a little more expensive than regular 87-up rotors. Nothing wrong with that, but i'm also thinking they might be really tough to find a few years down the road considering they were only used on that car. So I am wondering if maybe I would be better off using SN95 or t-bird control arms which I have read in the past will widen the front track by 3/4" per side? I would also think this might soften up the ride a little too considering the extra leverage on the spring. I do have camber plates, so I would think I could get the alignment correct.

[Capriman86]

How many miles a year do you drive on them?
There are still places that will turn them down if needed too in the future...just a thought.

[85GT-79FJ40]

Jeff, I do put quite a few miles on the car each year. Usually from late April to whenever they salt the roads it's pretty much my daily driver. And my house is 46 miles from work. It's also not unheard of to ruin a set of rotors in a day at the track. I haven't done it yet, but i'm sure I will eventually. I'm planning on some brake ducts as part of this too, but the regular rotors are available anywhere and the cobra rotors, although available are a bit tougher to find and more expensive should I need a set in a hurry. It's looking like I could pick up some used low mileage arms and regular later V8 rotors for only 30-40 more than cobra rotors. Of course i'm not sure if the outer ball joints are the same. I suspect they may not be. I'm concerned with possibly wacking out the geometry to the point where I have too much negative camber and start tearing through tires.

[Shelby1]

Buy a set of 1/4" wheel spacers for the front if you keep the '87-'93 GT front rotors. Problem solved.

[85GT-79FJ40]

Buy a set of 1/4" wheel spacers for the front if you keep the '87-'93 GT front rotors. Problem solved.

It's actually a 3/4" difference though. It's looking like I'm probably just going to go with the 93 cobra rotors. I would have to change the ball joints in the sn95 arms, which isn't a big deal but after taking a quick look at the car last night I also think I would have some camber issues. I don't like to run more than a degree of negative camber on the street.

[qtrracer]

I have sn95 a-arms on my 86 with a 13" Cobra brake upgrade. The ball-joint shank is shorter I beleive, so you probably can't use it with the 87+ v8 spindle. This a-arm does increase front track about .75" per side when using the 94/95 sn95 spindle, and helps recover lost camber due to the narower k pick-up points when used with the sn95 spindle. My MM cc plates more than provide enough adjustment to run stock-spec alignment or aggressive track alignment. Mathis used the T-bird a-arms to gain extra track (same as sn95) so I assume the ball-joint is the same as the Fox but might still present excessive camber - his was a track car so I'm sure he was delighted. Aside from the camber and ball-joint issues, I can tell you that fender clearance becomes a problem with the longer arms. First, you're right - the longer arm leverages the spring more which means the car will be lower than before all other things being equal. In my case, running "C" springs I lost another .5" by just adding the longer arms; this caused severe fender-lip clearance issues when just turning and/or hitting very small bumps at low speed with my 96 Cobra 17x8 wheels running 245/45/17s. Instead of seriously messaging the fenders, I elected to go coil-over and raised the front back up that .5" which all but elimenated the fender rubbing except on aggressive turns. A mild fender adjustment should take care of that. In short, with wider wheels/tires, you may have a bigger fender clearance issue than I have especially if the car is already lowered. Good luck.

[stevemilz]

Why not use the Cobra rotor?

Autozone Part#
54004 Cobra part#

5461 GT part#

[Shelby1]

It's actually a 3/4" difference though.

Ya' I know... Stock '84 rotors up front with 1/4" wheel spacers. Fits good and no track width issues.





My suggestion if you are stepping up to the '87-'93 rotors is to go with the '93 Cobra rotors. I don't think they will be too hard to find in the future... I dunno though it is your car and you can do what you like!

[85GT-79FJ40]

Yep, I'm just going to go with the correct cobra specific rotors. Not only is there potential camber issues, ride height issues, and the ball joints to change apparently quite often the tie rods wind up being too short as well. Not worth it just for cheaper rotors. Especially considering I just put new FRPP control arms on the car 2 seasons ago.

[86asccoupe20]

That car is gonna look sweet.

[Curtis]

How big are the Cobra rotors?

[MAD MIKE]

How big are the Cobra rotors?

Look to post #7. They are the same size as '87-'93 5.0 cars. The only difference was the '93 Cobra rotor had a thicker wheel mounting pad to compensate for the offset used on the wheels to match the wider rearend with the disc brakes.

Very sharp car Shelby1.

[Shelby1]

Look to post #7. They are the same size as '87-'93 5.0 cars. The only difference was the '93 Cobra rotor had a thicker wheel mounting pad to compensate for the offset used on the wheels to match the wider rearend with the disc brakes.

Very sharp car Shelby1.

Thanks Mad Mike!

[qtrracer]

. . . apparently quite often the tie rods wind up being too short as well.

Yep - forgot about this. With the added .75" track, the outer tie-rod does not engage enough threads to be safe. Need to go longer which can be done with factory parts - I beleive the Taurus end works. In my case, I went with the MM bumpsteer kit which was made longer for this application.

The 93 Cobra rotors are 11" just like the other Fox chassis v8 cars since 87; they just have the thicker mounting face.

[martin0660]

Need to go longer which can be done with factory parts - I beleive the Taurus end works.

Looks like the OP made up his mind, Just to add ... The SVO / Mark VII tie rod end is longer as well and works with even that much more length (wider than SN95 / T-Bird). I have SVO arms on my Capri, Flamming River fox manual rack, and Mark VII tie rod ends. Plenty of engagement.