Choosing the Right Tires for Your Foxbody Mustang

Using the right rubber can potentially have life changing results – it could be the difference between running a 13.xx and a 12.xx quarter mile or stopping 10 feet shy of a collision with a semi. Typically, tire choice plays a role in handling, acceleration, braking, road noise, and vibration. Different tires are going to have different characteristics across those categories.

In terms of Foxbody Mustangs, the original tires were sized as 225/60/R15 and were fitted on 15-inch rims (later on in development Ford went to 16 inch rims), which is pretty puny by today’s standards. Logically speaking, a larger tire ought to provide greater grip and traction. So with this in mind, what exactly can we fit?

• The largest wheel a Foxbody can accommodate without modifications is a 16 or 17 inch wheel
• Tires can be chosen from three main categories: high performance, drag radials, or drag slicks
• Drag radials and drag slicks are not necessarily DOT approved and are not recommended for street-only use
• The type of tire you choose should be dependent on your intended application and current power output 

The aftermarket has learned the largest wheel a Foxbody can accommodate on all four corners without any rubbing or clearance issues is a 16 or  17 inch wheel shod with 245-width tires (ex: 245/50/R16). Running a larger tire/wheel combo can certainly be done, but not without modifying your Foxbody. Problematic areas in the rear end are the fender lips, quad shocks, (if equipped) and the exhaust hangers. In the front, the fender lips and lower control arm are the major restrictions. Going larger than a 245 wide tire can lead to rubbing/hitting any of the above. If you're looking to go larger than a 245, read below.

Looking for different tire sizing calculations, or just want to see how much those new rims are going to throw off your speedometer? A tire size calculator will help you solve fitment and spacing issues as well as give you insight into measurements and differences between tires.

Having gone over sizing, we can finally dig into the meat of the matter – actually picking a tire. Considering a Mustang is a performance oriented vehicle, it's deserving of an equally performing tire. There are three main categories to choose from: high performance, drag radial or drag slicks. Each tire is designed very differently. Whereas one may excel on the drag strip, it will be awful on the road. Let’s go through them.

High Performance: High performance summer tires are pretty straightforward. They offer good performance across the board and have great road handling characteristics, making them perfect for daily drivers and weekend course warriors alike. Better yet, should the asphalt suddenly become wet, your pony will still be able to prance around without significant trouble. Due to the softer and sticker compounds used over traditional all-season tires, tread life is moderate. They won’t last as long as regular all-season tires, but nor will they be as short-lived as the tire types below.

Often branded as ‘drive to the track, race, and drive home on the same set of tires’, drag radials are a cross-breed between slicks and street tires. The mule of the performance tire world, if you will. Drag radials typically deploy an even softer compound than high performance street tires yet maintain a sturdy enough sidewall so the vehicle can still turn a corner (however, the sidewall is softer than a performance street tire). Furthermore, separating drag radials from a full slick, despite looking eerily similar, is a light tread pattern. This makes it so they're legal to use off the track. However, a drag radial on the street will never perform as well as a regular tire. If conditions get mucky, things can become a hot mess quite fast. Drag radials are best suited for the track with only light driving on the street. Tread life for this hybrid is not great, as to be expected with the stickier compound.

If you’re all about launching hard and racing down a straight line, these bad boys are for you. They offer uncompromised and unparalleled traction, but at the expense of everything else. Slicks are basically a big block of a very special rubber compound with no tread, maximizing contact area. Coupled with extremely soft sidewalls that deflect significantly under load (again, maximizing contact area during launches), slicks cannot be beat for an all-out drag racing Foxbody. Take note: slicks are only for track use. Their treadless and soft sidewall design is a recipe for disaster on a wet road or simple corner. As for tread life… what tread life?

The term ‘DOT approved’ means the Department of Transportation approved a tire for secret use based on certain test results (tread wear, hydroplaning characteristics, sidewall rigidity etc.). As the definition implies, all street tires sold in the United States are DOT approved. However, the same does not apply to drag radials or slicks. Certain drag radials and slicks may be DOT approved, but this certainly does not mean they are entirely suitable for the street. Exceeding the minimum and meeting the minimum are two entirely different things, and typically drag radials and slicks are in the latter category, thus not recommended for extensive street driving.

The type of tire you should shoe your pony with is entirely dependent on the intended application. Outfitting a daily driver pushrod 5.0 with slicks is not appropriate, nor is having your 9.xx-capable drag monster at the tree wearing some low-profile Sumitomos. In terms of brands, you can’t go wrong with any big name. Big name companies like Nitto, Mickey Thompson, Sumitomo, M&H, etc.; they all spend big coin and use the latest technology (despite my describing a slick as a ‘block of special rubber’). The compounds in today’s tires are highly complex to field the best possible tire.

Say you want to get a massive 275/50 rear tire on your Fox Body Mustang. There are a few modifications that need to be done to accommodate this. Earlier we confirmed a stock Foxbody (1987-1993) cannot accommodate a tire and wheel larger than 245/50/R17 without modification (17x9 wheel) – otherwise, the tires could rub or scrape against certain suspension and frame members. If running a 245/50/R17 tire/wheel combo isn’t enough for either your aesthetic or performance needs, it's possible to go bigger. However, as stated, it isn’t as simple as mounting the tire on the wheel and securing the wheel to the vehicle.

• The most cost-effective way of fitting big tires on a Foxbody is by rolling the fenders
• Flipping the quad shocks around in conjunction with rolling the fender lip will allow you to fit a larger tire in the back
• A stock Foxbody (1987-1993) cannot accommodate a tire and wheel larger than 245/50 on a 17 inch wheel without modification
• Aftermarket control arms are the best method to increase room for bigger wheels and tires while beating the stock control arms in virtually every way possible

First and foremost, the cheapest (and most rudimentary) way to get a little more room in the fender wells involves a hammer or baseball bat. Generally speaking, pulling out the hammer should be the last resort. In this case here, however, using a hammer to carefully roll the inner fender edge flat can yield a previous centimeter or two of additional clearance. What is meant by the inner fender edge? Well, if you reach up into the fender well and run your hand along the top most edge (do so carefully, it can be sharp), you will notice there is an outcrop of sheet metal perpendicular to the fender flare itself. During fabrication, Ford never bothered to flatten this edge down. A note of caution: quite often when hammering this area, the paint can crack. Using a heat gun to heat the area first can help, or better yet, there are specific automotive tools available to help the process. Rolling the fenders will help fit a larger tire, but it will also give some extra vertical room for those that have lowered or will be lowering their Mustang.

Further working with the idea to make what's already on your Mustang workable, if your car is equipped with quad-shocks, flipping them around in conjunction with rolling the fender lip will allow you to fit a larger tire in the back. Some guys go as far as to remove the quad shock completely, but this isn’t recommended as the quad shock is there for a purpose – to control the wheel hop allowed by the flimsy stock control arms during hard acceleration.

A popular mod for Foxbody owners, a 5-lug conversion, will affect your Mustang's tire clearance. You will have to adjust the suspension/wheel well areas if you are looking to fit a 255 tire on an 18 inch wheel. However, a 5-lug conversion will allow you to fit larger brakes, giving you enhanced braking. If you are looking to fit larger tires on your Foxbody by means of a 5-lug conversion, be sure to first consider how you will modify your Mustang to accommodate it, whether that be rolled fenders or new suspension parts.

The best solution also happens to be the most expensive (go figure!). The biggest problem in the rear of a Foxbody Mustang is the stock control arm geometry and accompanying quad shock. As stated, it isn’t a good idea to remove the quad shock and leave the stock control arm. However, replacing the stock control arms with an aftermarket design has a plethora of benefits. First off, aftermarket control arms no longer need the quad shock due to their superior design, strength, and geometry. With an aftermarket control arm, the quad shock is no longer needed (and probably won’t even mount). Secondly, aftermarket rear control arms are better packaged, meaning they take up less space in the wheel well. Even better, many aftermarket arms relocate the bottom coil spring perch slightly for maximum wheel clearance and better vehicle ride characteristics. So not only do you get more space for some massive rubber, but you also improve over the stock design in every department possible! Not a bad deal.

The front fender well of a Foxbody isn’t as big of an area for concern as the rear, namely because it is uncommon (and not particularly beneficial) to throw some fat tires up front. If you do need some extra space, the modifications necessary are similar to the back. The first thing to do is, of course, roll the fenders. Those with ‘91 and up Foxbody Mustangs are a bit luckier. As of 1991, Ford enlarged the front wheel wells, so you may not need to be as aggressive with your modifications.

After this, the major restrictions you’ll encounter are the front control arms and steering gear. Tight turns will often see the tires, and even the inside of the wheel, rub against the lower control arm. You can get additional clearance by installing aftermarket control arms. Like the rear, aftermarket units are not only stronger, but generally revise the geometry in a positive way as to augment handing and load transferring characteristics.