Aftermarket wheels on Cobra - optical illusion?

[Brookse]

Hi guys. Replaced my 17 X 7.5 stock wheels with the aftermarket 17 X 8.5 wheels. The back looks awesome. On the front, stayed with the stock size tires... I know the offset is different on these wheels, etc., but they do fit and look good (IMO) but the clearance when turning the wheel from the rear of the wheel well to the tire is really narrow. 1/2" at most I'd say, probably less like 1/3". I understand making the wheel wider by 1" will reduce the clearance when the wheel turns, but boy is it close. (The increase in backspacing is 4/10" by my calculations, so the front spacing must be 6/10" and that's where it gets hairy.)

So the question is: do you think this wheel is going to bottom out? There's lots of clearance on the top and the front, but I'm wondering how much travel I might see between the tire and the back of the wheel well? (Have the Ford C-springs in it.)

Also, can I change the rotor hat (as I need new rotors anyway) to a GT and will that fit and allow the wheel to move back inside the car a bit?

Or, do I go to a 245/40/17 tire say (from 245/45/17), to buy a bit of room?

I really don't want to run the Ford wheels at this time.

Car is still in the shop so by Monday I have to figure out what to do.

As always, your input is appreciated. Thank you.

[Mike S.]

Yes, swapping to GT front rotors will put the tires where they need to be. The rears will still be out a bit further than factory, but several members run them that way with no problems.

-MJS

[Brookse]

Good to know. I have new Cobra rotors on order. Can I just order a set of GT rotors (with a shorter hat I guess) and bolt them up? Anything I need to know?
Thank you for taking the time to let me know of my options.

[Mike S.]

Yes you can, the GT rotors go right on and have the shorter hat height. As easy as a swap gets.

-MJS

[Brookse]

Better call my shop first thing Monday morning. Thanks again for the help - it is really appreciated. Thank you!

[Brookse]

Well, my shop, which is thoroughly Ford (and these guys build their own parts for their own drag cars), says the GT rotors are smaller by 1/2", and shouldn't be installed. So they don't want to do it. Further, they are telling me the 8.5" wide wheels are rubbing and have no clearance on the Ford C springs. I'm really surprised by this. And a little PO'd. I honestly don't think they've done this before and are thus reluctant to do so.

So I'm leaving the old rotors on (new pads going in) on the old wheels and will try another shop.

It embarrasses me to ask this but you guys are 100% sure you can put 1993 GT rotors on a 1993 Cobra.

Thank you.

[93Cobra#2771]

100% sure. The rotors are identical except for the hat being 3/4" thicker on the cobra rotors.

Absolutely, positively 100% sure.

There are a few parts vendors that have them listed as different rotor diameters, but they are wrong.

[RollTide93]

Well, my shop, which is thoroughly Ford (and these guys build their own parts for their own drag cars), says the GT rotors are smaller by 1/2", and shouldn't be installed. So they don't want to do it. Further, they are telling me the 8.5" wide wheels are rubbing and have no clearance on the Ford C springs. I'm really surprised by this. And a little PO'd. I honestly don't think they've done this before and are thus reluctant to do so.

So I'm leaving the old rotors on (new pads going in) on the old wheels and will try another shop.

It embarrasses me to ask this but you guys are 100% sure you can put 1993 GT rotors on a 1993 Cobra.

Thank you.

look for some pics of my car when I first got it, had GT front rotors on it, they are set in a little on the front and mine was lowered

[Brookse]

I did a Google and if that is your red car it looks great. Are those the cheapo aftermarket 8.5" inch wheels I have with GT brakes? They look like they fit just fine.

As for me, I'm leaving it as is, for now. I've got tires on the 8.5" aftermarket wheels and will put them on myself to see how they run and then get to another shop to see about the GT rotors. Just waiting on the jets (going to 125) and a few dyno runs. I love my shop but shit are they s-l-o-w....

[Brookse]

Hey all, for what it's worth:

Just got my car back from the shop today. I haven’t even washed the friggin' thing yet this year. It's gone from garage to shop.

I went in to get some new jets on the Nitrous to run a 125 hp shot, and it all went fricking sideways. I got them to put new brake pads on too and from that came new rotors, new tie rods, new ball joints and a new fan. $1,200 before they even looked at it. The thing tracks now like I can't imagine. Is that to be expected? WTH?

Then, I had them put some drag radials I got on some re-po Cobra wheels. The back fit and looks friggin awesome but they’re saying the fronts don’t fit. I know they'll rub, a bit, but I'm going to put them on this weekend to see for sure. This is with the Cobra rotors, they didn't want to put on the GT rotors.

Then, I had them run the car on the dyno. Base line run to see what it’s making as is – no nitrous. The friggin air-fuel ratio went off the charts (lean) at 5,000+ RPM so they shut it down and I’ve got no nitrous right now. So what’s that going to cost to find? Another $1000? They said it'll probably need a new chip, though the original chip did fine last year. Any thoughts?

On the bright side, the numbers the car ran stock are great. At the wheels, HP maxed out at 282, which is 361 flywheel (using a .78 correction which my guys say is quite accurate up here in the Rockies) and torque was a tire shredding 310 at the wheels, or 397 at the fly wheel. They said with proper AF add another 10 or 15 to those numbers. If I ever get the NO2 working, I'm expecting horsepower will be 400+ and torque 500+ (hence the drag radials). And all this in a 3,200 lb. car. These numbers should put me in the low 12s as is, and in the high 11s with NO2. Can't wait to try and crap out a tranny or something.

But any thoughts on the devilsh NO2 would be most welcome. It's a ZEX BTW. I have no idea why it ran great last year and after a winter hibernation is all over the map.


Thank you.

[trackpilot]

My old Cobra had GT rotors on it when i bought it. But when you turned the wheel for a tight turn the tires would rub. So i got rid of em and got some Cobra rotors and no more rubbing.

[RollTide93]

My old Cobra had GT rotors on it when i bought it. But when you turned the wheel for a tight turn the tires would rub. So i got rid of em and got some Cobra rotors and no more rubbing.

had the same issue with mine

[93Cobra#2771]

There was actually a ford part created to address that issue. A steering rack limiter. Essentially it kept you from turning the wheels to sharp and kept the rub from happening...

[Brookse]

Hey, as a side-note, I put the aftermarket 8.5" aftermarket Cobra wheels on the front today. Yeah, they stick out a bit, but they look fine from the side and back. From the front, maybe a little guido, but just a bit. They don't rub like my shop said they would.

One thing I noticed is that I took a square to the wheel/tire, and noticed that the passenger's side is 1/2" past (outside) the fender, but the driver's is 3/4". Not a big difference but shouldn't they be the same? I know the rearend has tolerances but the front too? Seems odd one wheel would be 1/4" farther out than the other. Or could it be the body is out somehow? Thanks again.

[103teal]

Hey rolltide. I have a question. When I'm driving and I turn to do a u turn my wheel is hitting the control arm. Ive looked at a bunch of pictures of everyone elses cobras and the front wheels and they look like they are spaced like mine. Did someone put the wrong rotors on mine at somepoint?
The other question is if I put the cobra rotors on wont the wheels stick out to far?