Blog Post on Wheel Specs for the 94-98!

[b.mad@MaddRetros]

Hello,

In this post we will be talking about wheels. There is not a lot of information about wheels for the SN95, which is important when wanting a set of aftermarket wheels that are not Mustang-Specific.

 

Full link here: https://maddmotorsportsdesign.blog/2017/10/10/sn95-1994-1998-wheel-specsoffset/

 

We will be using terms that are unfamiliar to some, or some that I made up to help grasp the concept of specs.

• Mounting surface: The mounting surface of a wheel is the surface that touches the rotor hat.
• Backspacing: is the space from the mounting surface to the edge of the inner rim (to the back)
• Front spacing: is the space from the mounting surface to the edge of the outer rim (to the front)
• Offset: Where the mounting surface sits in relation to the width of the wheel.

So first and foremost, you need to determine if you are going to run the conventional coil-spring setup, or if you are going to run coil-overs. Because it matters. Coil-overs will give you less backspacing to play with because of the diameter of the coil-over combo. Also, if you are using 94/95 spindles, or if you are using 96-04 spindles. There are other things to take into consideration like camber specs, however, all you have to remember is negative camber will cause the top of the wheel to sit more inside of the fender.

To keep things simple, we are only going to talk about offsets for SN95's with coil-overs, specifically with a Maximum Motorsports/Bilstein coilovers w/2.5" ID coil in the front and 2.25" ID coil in the rear. Keep in mind that the taller the overall diameter of the tire is, the less room you have to play with. If you use spacers, it will increase the front spacing, while keeping the backspacing. Also, caliper clearance is very important when discussing specs. The "pad" should be sufficient for whatever caliper you are using.

If you are using the 94/95 spindles, you will have a 6.23" backspacing before you hit the coil. And you have about 3.77" of front spacing. That means you can fit a 10" wide wheel up front with an offset of +18.

For the 96+ spindles, it moves the wheels outward about 5MM per side, as per Maximum Motorsport's website. That is a backspacing of 6.42" and front spacing of about 3.58". You can have a 10" wide wheel up front with an offset of +23.

In the rear, if you want a wide wheel, be prepared to potentially remove the quad shocks. You should not have anything wider than an 11-11.5" wheel. The reasons for that are:

1. You will need to pull your quarter panels and bang the crap out of the inner fenders, and
2. You will have a hard time getting in and out of driveways.

You have about 6.98-7.23" back spacing before you really start having issues. And about 4.27-4.52" of front spacing. So if you really want to push your luck, you can fit an 11.5" with +18 offset, or be a little safer with an 11" with a +20 to +25 offset.

How do tires play a role? If you are worried about clearance, you will need to keep the tire size in mind because if you are going wide, it will limit your clearance. For example, you have an 11" wheel. You can use a 295 (11.5"), 305 (12"), or 315 (12.5"). A 295 will not take up as much room as a 315.

For reference, I ran a 19x9.5 +25 with a 275/30/19 in the front, and 19x11 +25 305/30/19 in the rear, running -1.5* camber, lowered about 2" all around. This is how it fit.

Front:

Rear:

Rear clearance:

Overall:

Another reference is Cody Fodder's 1994 Cobra. He is using 17x10 +18 all around on 275/40/17 Falken AZENIS RT615K+. He is using a +25mm spacer in the rear.

To give you an idea of how close these specs are, someone tried to mount their 285/40/17 17x10 +18 in the front, and it hit their coil-over. So, in that case, I would recommend a 265/275 tire. Also, another idea how much space a coil-over robs, Colin Austin from Das Hengst mentioned that an 18x11 +23 will fit in the front of the SN95 with a conventional coil-spring setup.

Disclaimer: These are estimated specs and in no way guaranteed. Madd Motorsports will not be responsible for incorrect fitment of wheels and not responsible for any injuries, any damage whatsoever, or for incorrect installation. This is a guide meant to help, it is in no way guaranteed.

Also, Colin mentioned that the 1994-1998 SRA specs are very similar to the 1999-2004 SRA specs. The may vary ever so slightly. Also, you would be able to fit an 11" wide wheel with a +23 offset in the front of a 1999-2004 Mustang with a conventional coil-spring setup. We recommend that you contact a custom wheel dealer or manufacturer that understands Mustang offsets really well.

 

Edited November 23, 2017 by b.mad

[b.mad@MaddRetros]

post updated with more specs