Fox Tire options for 90 fox with 17x9s

Bdude93

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Oct 16, 2020
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Doing a ground up restoration on a 90 foxbody. Planning on doing a cobra clone body kit.

have swapped to sn95 spindles and 10th anniversary cobra calipers and tubular A-arms. I’m wanting to put on machined 03 cobra wheels (17x9). Was hoping someone could share with me how big of a front tire I could utilize without rubbing? I hear talk of the wheels making contact if they’re too big. I’ve not personally experienced this before. Is it contacting the control arms? Fenders?
Would rolling the front fenders help with clearance? If so would that affect the mounting points for the inner fender spats?
I was HOPING for a 245/45R17 with rack limiters, if needed. My understanding is that would stop it from making suspension contact.
I’ve considered swapping out to 91-93 fenders but the reproductions seem REALLY thin and flimsy and I’ve heard of them not lining up to the bumper very well. Sourcing take offs in solid condition hasn’t panned out yet. So was hoping you guys could share your thoughts, experiences and knowledge given my setup.

LMR has some review pics of these wheels on a notch LX but it looks to be a 92-93, I believe. Anyone know approximately how much more clearance you got from 90 to 91?

thanks for the help

brandon
 
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Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
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Not enough info really.

Which spindles? Which tubular control arms? What is the BS/Offset on the wheels?

For instance, 96+ spindles are wider than the 94-95 which means the wheel's arc it travels in when you turn side to side is wider, which can cause issues with rubbing the fenders, but 94-95 spindles pull it in slightly, which lessens the arc issue, but can cause rubbing on the A-arm. Rack limiters can help with this.
 

Chuckman

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That sounds about the normal offset for a fox, a 245/45 should be fine depending on how low you are, definitely would not go narrower on a 9" wheel, they're really meant for an 8". A 255 or even a 275 would be a better fit for that wheel but it gets a little dicy without modding stuff more. Front fender ground effect may rub slightly on a gt without limiters or trimming (at least mine did, only at full lock)
 

Bdude93

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I just put on LMR coil overs so I’m hoping for a fairly low aggressive stance. I wish they made these in an 8”.
My last ‘88 i bought some cobra Rs off a friend (this was close to 20 years ago) they were 245/45 in rear and he had 235/45 up front cause he said they were rubbing but never specified where. All brakes and suspension on both of our cars at the time were factory
 

Mustang5L5

Put lubricant all over the balls
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They kinda do make them in 8”. If you sold them abs tracked down some 98’Cobra wheels, you’d have a similar wheel in 17x8. You could also send the fronts off to Weldcrsft and have them narrowed to 8”

really a 9” wheel should use a 275 width tire. An 8” wheel uses a 245/255. So running a 245 on a 9” rim can seem kinda silly.

but safest option will be a 245 up front. 255 might work. Definitely run the rack limiters
 

Warhorse Racing

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When choosing tires, it's a good idea to look at the Rim Width Range and the Measuring Rim Width. You will find that several 245/40/17 tires have a RWR of 8-9.5 inches, and a MRW of 8.5 inches, which means they will be slightly stretched, but not overly stretched on a 9" rim. The BFG Rivals I use on my 1992 Mustang GT autocross car are 245/40/18 mounted on 18x9" rims. The 18" rims probably won't work on your car, but it does prove that some 245 tires will work fine on a 9" rim.

Your coil overs will be wider than stock struts, due to the springs, that might impact how well your rims/tires fit. Because production tolerances weren't very tight, no two Fox Body Mustangs are exactly the same. When trying to fit the widest tires possible up front, it often takes some experimenting and finessing.

This video covers the tires I used on my Fox; it's not a 1 to 1 comparison to what you're doing, but the section that goes over how I chose my tires might provide some useful information:

View: https://www.youtube.com/watch?v=Jkq7v8xl2jg&t


This video covers how to choose the right rim and tire size. It should also help inform your rim/tire decision:

View: https://www.youtube.com/watch?v=-FpptiBXBio&t


If you have any questions, please ask. I'm happy to help.
 
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TriSUm

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Jan 23, 2002
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Here you go... 93 Coupe, MM front arms, 95 spindle, 17x9 Cobra wheel (6.02 BS / 26mm offset). 245/45 in the front and 275's in the back. No rubbing on mine.

Not the best picture, but you can see them.
20201218_145043.jpg
 
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Bdude93

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So the trend I’m noticing is all the cars mentioned are 91-93 foxes... thinking to get what I want I may need to source some 91-93 front fenders, lol
 

Warhorse Racing

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So the trend I’m noticing is all the cars mentioned are 91-93 foxes... thinking to get what I want I may need to source some 91-93 front fenders, lol
The difference between the early and late Fox Body fenders is in the area in front of the tire, where the trim goes. The 91-93 cars have a shorter section ahead of the tire, and the trim piece is also shorter. This was done to provide clearance for the Pony wheels. If you do an image search for the difference between 87-90 and 91-93 Mustang fenders, you can find photos that compare the two. I haven't measured this personally, but the difference is listed as 1.25 inches.

Do you have a 245/45/17 tire mounted on a 17x8" or 17x9" rim that you can test on your car (maybe one from a 99-04 GT)? If I recall correctly, the 90 Mustang came with 255/60/15 tires, which have roughly the same Overall Tire Diameter as a 245/45/17: approximately 25.6". A 245/40/17 has an OTD of 24.7". The shorter sidewall will provide more clearance and allow for better handling. I can't guarantee that this will fit, but it's worth testing before you decide on new fenders. You might be able to get away with minor trimming of the fenders/trim in front of the tire.

Keep in mind that even though tires are listed at the same size, there can be differences in the specs.
 

Chuckman

GTFO you fat, heavy bastard
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So the trend I’m noticing is all the cars mentioned are 91-93 foxes... thinking to get what I want I may need to source some 91-93 front fenders, lol
My 89 with b springs, 17x9 245/45. Slight rub at full lock on the front by skirt, an lx would be fine, and a rack limiter would stop it as well.
 

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Mstng93SSP

You have a nice rear end there Dave.
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I have 2 1990 foxbodies. This one has 18x9s with 245s up front and 275s in back with no rubbing. Similar setup to yours. 94/95 front spindles, fox length rear 5 lug axles etc. I had 17 inch cobra R rims on this car before with 245 in fron and 275 in back same deal, no rubbing.

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Blueinfan

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I have 2 1990 foxbodies. This one has 18x9s with 245s up front and 275s in back with no rubbing. Similar setup to yours. 94/95 front spindles, fox length rear 5 lug axles etc. I had 17 inch cobra R rims on this car before with 245 in fron and 275 in back same deal, no rubbing.

uzxeAa.jpg


3jRgiq.jpg
I have the same car but mine is not that nice! Can you take pics of he inside, plz.
 

Blueinfan

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DAMNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN! Its clean!!! I have the same car but changing it to black interior!!!
The car is jacked up because a kid was driving it around. Wires are cut and parts missing. But I have restored them but missing the rear quarter panels.
 

Mstng93SSP

You have a nice rear end there Dave.
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I have 2 sets of convertible rear quarter panels for a convertible. Your car is a convertible? Hatch?
 
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