What Size Tires will Fit my Truck?

Choosing the right size tires to fit a truck can be a fairly straightforward task or a task that is wrought with complications, twists, and turns. In fact, the difficulty level of determining what tires will fit on any given truck hinges almost completely upon whether or not there is a need for non-stock tires. If stock tire sizes are needed, then the entire task of determining which tires the truck needs is simple. Non-stock tires require a lot of consideration, especially if there is a purpose behind the decision to abandon stock tire sizes.

Those looking for replacement tires that meet manufacturing specifications only need to know those specifications. There are a few easy ways to get the specifications, but before covering those methods it is important to understand the specifications and how to decode them. The entire auto industry uses tires, and thus it is not surprising that a uniform rating system was developed. The markings on all tires, including truck tires, generally starts with the name followed by a series of letters and numbers that looks a little something like this: 195/60R15.

The numbers before the slash describe the width in millimeters of a properly inflated tire at its widest point. The number after the slash is actually a percentage, and is used to describe how tall a properly inflated tire is from the edge of the rim to the tread. In the case of a 195/60, the width is 65% of 195 millimeters, or 126.75 millimeters. Note that truck tires tend to be tall and the wheels themselves also tend to be large. This is mostly due to the weight that needs to be distributed over all tires and the momentum trucks need to generate to accelerate or decelerate without wearing out their tires. The R simply means that the tire is built in radial fashion, which is normal, and the number after the R indicates the diameter of wheel that the tire fits. If a truck has 16 inch wheels, then the 195/60R15 simply will not fit.

Other important markings to consider are the M&S ratings, severe snow service label, pressure markings, load ratings, and speed ratings. M&S rating and severe snow label are actually both labels, and are designed to indicate a tire designed to perform in snow, or in mud and snow in the case of M&S. A pressure marking indicates the proper tire pressure, while load rating is an index that rates how much a tire is rated to safely carry; larger numbers are generally better for those looking to tow or carrying big loads frequently. The speed rating is a similar affair, but is measured in letters. Unfortunately, a guide is required to decode the speed rating of tires, but letters that come later in the alphabet generally indicates compliance with standards that would permit higher performance/high-speed operation.

If the wheels and tires on a truck are stock, then it is usually a simple affair to read the tire codes and know exactly what is needed. If the vehicle was purchased second hand, that information may not be reliable. In such an event, try looking for a manual that the manufacturer included with the vehicle when it was sold. Failing that, the Internet is a good place to look up specifications for tires without being hassled by salespeople. Site such as Online Tires have quick search features that ask for the make, model, year, and sometimes trim level of a vehicle to provide stock tire specifications and purchasing options. These same tools have long since been available to repair shops and vendors of tires, but using these tools generally comes with salespeople asking for sales, which can be annoying to some.

Those who are not using stock tires will need to make their decisions based on their needs. Wider tires generally offer more towing capacity and breaking performance at the expense of overall top speed and sometimes maneuverability. Taller tires may make off-roading or managing bumpy trails easier, but they also may change the towing dynamics of a vehicle and make towing dangerous or impractical.