Nothing changes the look and attitude of a car like wheels and tires. Changing from sleepy stock rollers to race-inspired aggressive wheels, or big and flashy hoops, really sets your car apart from the rest and makes it your own. All the body kits, styling accessories and paint in the world can’t make the kind of impact a set of wheels does, but get it wrong, and all bets are off. How many times have you seen an otherwise killer Mustang only to cringe at the sight of a set of poorly-fitting wheels or a style that just does not match the rest of the car? Wheel choice and fitment makes or breaks the entire car, so you need to take your time and choose the right set of wheels, not just go for the “deal of the week”.

There are several key aspects to wheel choice, and every car is different, so what looks good on a ’65 Mustang is probably not going to work on a 2009 Fusion; it might not even look right on a ’65 Falcon. We have taken the time to breakdown each area of consideration for you. This is a basic guideline, wheel choice varies by owner.

Style- There are many styles of wheels, with every manufacturer building many different designs in each style. Since we are talking about Mustangs and Ford cars, the truck-style rims are not included. The most common styles are Modern, Classic, Retro, Stock and Tuner.

Stock- This can be either actual stock wheels, modified stock wheels (such as widened wheels), or aftermarket wheels designed to look like stock wheels using newer materials or even larger diameters. You can buy a Magnum 500-style wheel in a 17” diameter, where the original wheels were 14” and 15” diameter. These are a great choice for restorations and stealth “sleeper” style cars.

Classic- The Classic aftermarket wheel style refers to styles of wheels that have been around for many years, like the Cragar SS, Torque Thrust, and slot mags. There are many classic wheel designs to choose from and these are best suited for resto-mod cars.

Retro- With the retro theme continuing to burn red hot, Retro style wheels are just as hot. For our definition, a Retro wheel is one that emulates a factory style or classic wheel but uses modern materials like billet aluminum and forged aluminum in larger diameters; 17- to 20-inches and larger. Retro wheels look great on anything, vintage or late-model.

Modern- When it comes to Modern wheels, definitions are more difficult since there are just so many designs. A Modern wheel is typically 17-inches or larger, made of aluminum and does not fit into any of the previously mentioned styles. Some Modern wheels look great on vintage machines, but most do not.

Tuner- This is a subsection of the Modern wheel design. The Tuner wheel is typically comprised of multiple spokes that are thin and lightweight. Tuner wheels look great on late-models, and can look good on vintage Fords, but the rest of the car has to match.

Wheel type- Aside from design, the type of wheel is important too. Most builders need a street type wheel, which is DOT legal. This means that the wheel is capable of withstanding regular use under varying conditions. Drag race wheels are lightweight, which is great for reducing vehicle weight and rolling mass, but under high-speed cornering, not so great. Make sure the wheels you choose are street legal.

Size- There are considerations beyond just what looks good. Safety is a factor in wheel choice. Going larger than 18-inches in diameter can put more strain on the brakes, especially if you are rolling with drum brakes on an older car. Diameter is not the only potential hazard, narrow wheels such as the classic pro-street “big and littles” can lead to a rough day of commuting. Narrow wheels (and subsequent skinny tires) have less contact patch and rolling resistance on the street. This makes them good at reducing friction, letting the car go faster, but less contact patch under braking is a bad thing considering most of the braking is performed by the front brakes. Many a street machine has met its end due to narrow front rollers.

Build type- Beyond the steel wheel (which are typically two-piece welded construction), there are four main build types for aluminum wheels- Multi-piece, cast, forged, and billet. Each with their own pros and cons.

Cast- The cheapest and heaviest of all the aluminum wheels, Cast wheels are formed by pouring molten aluminum into forms. This is a quick way to make a wheel, but at the same time this makes for a more fragile wheel. Curb-checks and potholes are mortal enemies of the cast wheel. They may be cheap, but they break and can’t be repaired. Cast wheels are also typically painted or chromed, which eventually chips and flakes, resulting a bad look.

Forged- Forged Wheels are made in a similar fashion to forged pistons. A slug of aluminum is forced into a form under extreme pressure to take the shape of the new wheel. This process uses several dies and takes time to manufacture. Then the wheels are machined to the final fit and finish. Forged wheels are the lightest of all the aluminum wheels, and the strongest. That said, the designs are more limited because of the manufacturing processes and they are more expensive. When bent or damaged, these wheels can be repaired in most instances.

Billet- These wheels start out as a solid chunk of high-quality aluminum, then it is machined to fit and finish. This produces a lot of waste aluminum and takes a long time to produce a single wheel. This makes them more expensive than cast wheels, but they are quite strong. Billet wheels are nearly as strong as forged wheels, but weigh a little more, thus more rolling mass, which can be an issue with large-diameters (20”+) and stock brakes.

Multi-piece- These can be a combination of any of the above constructions. Most often, the hoop (the part the tire mounts to) is forged or billet and the center is one of the three other forms. A cast center piece is not as strong, but that portion of the wheel is less likely to fail than the hoop. A cast hoop and a cast center, not so good.

Once you have picked out a design for your wheels, you need to figure out what size and specs you need. Most Ford cars use one of two bolt patterns; 5 on 4 1\2” and 4 on 4 1\4”. If you have a vintage small to midsize car, or a 4-lug Mustang, you will likely have the 4 on 4 ¼” pattern. You need to know what your bolt pattern is before you pick out your wheels, as many wheel designs are only available in specific bolt patterns (such as 5 lug only). If you are unsure of what bolt pattern you have, you can measure it. To measure a 5-lug bolt pattern, measure from the center of one stud to the outside edge of a stud that is across from (not next to) the first. For even-numbered lugs, you simply measure center to center across two lugs.

The other critical fitment of a wheel is the backspacing. The backspacing is the measurement from the back of the wheel (where the wheel mounts to the hub) and the inside wheel lip. This is critical because too much back spacing and the wheel can hit suspension and steering components, or position the tires too close to the inner fenders. On the other side of the coin, too little backspacing can result in a wheel\tire that sticks out too far.

You must also consider the type of brakes that your car has. Disc brakes require larger wheel diameters, most 14” wheels do not fit with disc brakes, but there are some that will. For vintage cars, converting to disc brakes from drums can wreak havoc on the wheel fitment, so if you are planning on upgrading to disc brakes, take that into consideration when you choose your wheels. Most big-brake kits (13-inch and up) require 17” wheels or larger.

Tires can be a tricky decision too. You really have to choose the wheels and tires at the same time, as a mistake here can be costly (ask how we know…) in more ways than one.  Tires that are too tall can rub and change the final gearing of the car, too wide and you run the risk of cutting the sidewalls. Tire sizes have long confused consumers with the sizing codes that don’t seem to make much sense. In reality, they are pretty simple. For example a 295\40ZR20- The first 3 digits are the cross-section width in millimeters, 295 millimeter wide; the second set is the aspect ratio in percent, so this tire has a sidewall that is 40% of 295 millimeters. Next the speed rating (sometimes this is noted after the wheel size), Z which says the tire is good for 149+ MPH. The last number is the wheel diameter, 20 inches. Using simple math, the height of the tire can be calculated from these numbers-

295\25.4 to convert mm to inches= 11.4 inch cross section width

295 x .40= 118 mm

118\25.4 to convert to inches= 4.645” this the sidewall height

4.645 x 2 for the top and bottom side walls= 9.29

9.29 + 20 to get the overall height- 29.29

This will get you very close to actual measurements. This tire size in a BF Goodrich G-Force Radial TA KDW tire for example measures on a 10-inch wheel at 30 inches tall and 12 inches wide, so there are some manufacturing variances at work too.

Tires are also rated in terms of traction and treadwear. A treadwear grade of 400 (typical for a basic non-performance street tire) lasts twice as long as a tire rated at 200. Ultra-high performance tires are typically rated in the 200 and sometimes sub-200 range. They are softer (which means more traction) but they wear out much faster. Traction is rated in letters, from C to AA. C is the lowest rating, where AA is the best. The traction rating refers not to dry pavement, but skid resistance on wet pavement under controlled conditions.

You may be tempted to by an ultra-high performance tire for your muscle car or Mustang, but there are some things you should know about those types of tires. UHP tires are in most cases “summer” tires, which means they have little to no traction in snow or on ice, so if the car is a daily driver, you need to consider different tires or keeping a set of “winter” tires for the cold months. UHP tires do however tend to have excellent wet traction ratings. Another note on tires- don’t buy drag radials and drive on them every day, this just dangerous. Even though they are rated for DOT street use, does not mean that they won’t break loose the second they hit a puddle, because they can and do lose traction in wet conditions.

Sources:

BF Goodrich

http://www.bfgoodrichtires.com/

Cragar

http://www.cragarwheel.com/

McGard

http://www.mcgard.com/