Wanting wider wheels

Apr 20, 2020
70
16
18
32
Oklahoma city,Oklahoma
I recently bought a set of 18 inch wheels and they have 245/45 r18 right now. I'm wanting to go wider on the tires. How wide can i go without having to beat the undercarriage for clearance or rubbing? Thanks for any advice or help the 245/45 just doesn't look wide enough in my opinion.
18×9 wheels all the way around
5 lug swap of sn95 with stock brake setup and not sure of the offset or backspacing of wheels i bought them used
 
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Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
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Not enough info. Need to know what your rear axle/brake setup is, and what the offset and backspacing is of the wheels
 
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Mustang5L5

i'm familiar with penetration
Mod Dude
Feb 18, 2001
35,668
11,668
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Massachusetts
So if it’s SN95 axles, you bigger concern is rubbing the fender lips with 9” wheels more than inner wheel well clearance unless your wheels have deep backspace.

No real way to answer without knowing if your wheel sits to the outside, or does in fact have adequate backspace. There’s just so many combinations with these cars hence the need for offset/BS soecs
 
Apr 20, 2020
70
16
18
32
Oklahoma city,Oklahoma
So if it’s SN95 axles, you bigger concern is rubbing the fender lips with 9” wheels more than inner wheel well clearance unless your wheels have deep backspace.

No real way to answer without knowing if your wheel sits to the outside, or does in fact have adequate backspace. There’s just so many combinations with these cars hence the need for offset/BS soecs
I will try and find that information out thanks
 
Apr 20, 2020
70
16
18
32
Oklahoma city,Oklahoma

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
Well, the two go hand in hand, they make things that bolt to the axle hub that can measure the inside of the wheel house that can tell you exactly (if used properly) how much room you have to fit wheels/tires.
You can look at compression and rebound area and even (on a stick axle) tire tilt, (what happens going over irregular bumps) also side to side movement. All these things should be considered when chosing wheel/tire size.
But you know all that.
People come here all the time with 'how big can I fit' and get 5 or 6 different answers ' I'm running this or that size with no problem' but as you have found tire dimensions are not uniform, what works for some will not work for others and wheels/tires are a major investment.
Be ready to compromise. JMO
 

Warhorse Racing

Active Member
Feb 10, 2019
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Sorry if this is too much info, but there are lots of variables in play when it comes to fitting wider tires on a Fox. The first thing I'll say is that, for performance driving (track & autocross), you want to run a square setup, not a staggered setup. Staggered wheels and tires create understeer in a car that already has understeer from the factory. If this is purely for looks (and you are willing to accept worse performance), many people decide to run a staggered setup.

My 1992 GT has 03-04 Cobra brakes with 96-04 spindles (I know the 94-95 spindles are preferred), and a 1998 Cobra rear end assembly. So, if you have 94-98 length rear axles, my setup is similar to yours. I'm running American Muscle FR500 18x9" 5-lug rims. These rims are listed as having a 30mm offset/6.20 BS. Most rims will have a number stamped on the back next to "ET". That number is the offset. My AM wheels have "30" stamped near the "ET". Take a minute to check your rims, you might find your offset.

My AM wheels sit flush with the fenders, I've never had to roll them; I have quad shocks in place, and I haven't had to clearance the inner fender area. I run Ford Racing C Springs, so my car isn't lowered very much. I have never had an issue with tires rubbing.

In the past, I used a 275/35/18 Nitto NT05 in the rear and a 255/35/18 NT05 up front. I currently run a 245/40/18 BFG Rival S 1.5 on all four corners. Tire choice makes a huge difference. My smaller BFGs are MUCH faster than the Nittos.

As for tire size... Tires listed at the same size can vary greatly. When choosing tires, look at the section width and the measuring rim width. You might find that a 265 from one brand is nearly the same size as a 275 from another brand when used on your rims. Deviating from the measuring rim width will also stretch or pinch your tires, slightly changing the width.

Not everything in these videos will pertain to your question, but there is info in them that should help inform your decision.

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


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


If you have any questions, please ask.
 
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