We get this question every day - "what size off-road tire will fit your vehicle?"

The answer depends on more than just the vehicle’s make and model. Today’s 4WD vehicles come with many factory options, and factors such as suspension setup, body components, wheel specifications, and the added weight of accessories can make fitment different from one vehicle to the next.

The following process is a simple way to establish a rough baseline for what size off-road tire will fit your vehicle. There is no substitute for a proper trial fitment, which we always recommend, but these steps will help you understand the variables involved and get closer to the right size. 

Keep in mind that what may be a small uptick in size can make a huge difference in the looks of a vehicle.

While selecting a tire or wheel, it is important to stay within the manufacturer's recommended width range to ensure proper fit, handling and safety.  Tire and wheel combinations within the recommended width range provide the best steering response, stability and traction.  Fitments of tires that are too wide or rims too narrow increase sidewall flex, decrease handling response, increase braking distances and expose the center of the tire tread to accelerated wear and overall decreased traction.  Fitments of tires that are too narrow or rims too wide reduce sidewall flex which can decrease ride quality, increase braking distances, decrease traction as well as expose the outer edges of the tire tread to accelerated wear.

When asking, "what size off-road tire will fit your vehicle," park the vehicle on a level, solid surface. Make sure the tires are inflated to the pressure listed on the driver’s-door placard.

Using a tape measure, measure from the ground to the top of the tire and write down that measurement. This gives you the installed height of your current tire.

Turn the steering wheel until the front tire’s highest point—or apex—is closest to the fender, bumper, inner fender liner, or any other component that could interfere with the tire.

Measure the remaining clearance between the tire and that closest point, then write it down. This is just part of learning what size off-road tire will fit your vehicle.

Next, determine how far the front suspension can compress. Locate the bump stop and measure from the center of the rubber or urethane bump stop to the surface it contacts, commonly called the striking plate.

This measurement can be difficult to access on certain vehicles. If you need to raise the vehicle to measure it, always use proper jacking procedures and secure the vehicle with correctly rated jack stands.

The bump stop is usually located inboard of the tire, so the tire itself may travel farther than the bump-stop measurement suggests. The exact relationship varies by suspension design and bump-stop placement. As a basic estimate on many modern suspensions, we often double the bump-stop clearance. For example, if the bump-stop gap measures 3 inches, the tire may move roughly 6 inches through its suspension travel.

Something to consider when asking, "what size off-road tire will fit your vehicle," is the maximum tire diameter. Now compare the suspension-travel estimate from Step 3 with the clearance you measured in Step 2. This helps you visualize where the tire will move as the suspension compresses and provides a baseline for estimating the maximum tire diameter that may fit.

For example:

• Your current tire measures 30 inches tall.
• You measured 8 inches of clearance at the closest interference point in Step 2.
• Your bump-stop gap measured 3 inches in Step 3.
• Using the basic doubling estimate, the tire could move approximately 6 inches during compression.

Based on those measurements, a 32-inch tire may be a reasonable starting point for fitment. This estimate assumes you are retaining the same wheel and using a tire of similar width. It is not a guarantee—wheel offset, tire shape, tread design, suspension geometry, and real-world articulation can all change the result.

Check rear-tire clearance as well when discovering what size off-road tire will fit your vehicle. This is typically easier because you do not need to account for steering angle—unless your vehicle happens to have rear-wheel steering.

Measure the clearance around the rear tire at likely interference points, including the fender liner, inner wheelhouse, mud flaps, frame, suspension components, and bumper area. Remember that rear suspension compression can also bring the tire closer to these areas.

It is common for vehicles equipped with rear coil springs to have tire clearance issues on the rear wear the frame bulges for the coil spring, especially when stock wheels are being used.

This is where tire fitment becomes more complicated. If you plan to use your existing wheels, first confirm their diameter and width.

Wheel diameter is easy to identify: it is the final number in the tire size. For example, a 265/70R18 tire uses an 18-inch wheel.

Finding wheel width can take more work. If you are certain the wheel is original factory equipment, the driver’s-door placard may list the wheel size along with the tire size and recommended air pressure. For example, it may list an 18x7 wheel.

Keep in mind that dealers sometimes change wheels and tires before a vehicle is sold. The best way to confirm wheel width is to measure it. Specialized wheel calipers can do this accurately, and many aluminum wheels have their size cast into the back of the wheel. A reputable tire shop should also be able to measure the wheel for you.

Once you know your wheel size, use the tire manufacturer’s specifications to confirm the following:

• Select the tire diameter you want for your wheel diameter. In our example, that would be a 32-inch tire for an 18-inch wheel.
• Choose the tire width you want.
• Confirm that the tire manufacturer approves that tire size for your wheel width.

After selecting a wider tire, return to the vehicle measurements you took earlier. A tire that is 2 inches wider than stock will generally move about 1 inch closer to the nearest interference point on each side of the tire. That reduced clearance can create rubbing even if the overall tire diameter remains the same.

Changing wheels follows a similar process, but you must compare both wheel width and wheel offset with your factory wheels.

You can get the new wheel’s width and offset from the manufacturer. Your stock wheel width can be found on the door placard, in factory specifications, or by measuring it. The more technical part is comparing wheel offset.

Wheel offset is the distance between the wheel’s centerline and its mounting surface. While aftermarket wheel manufacturers provide this specification, finding the exact offset of your factory wheels can be more difficult. Measuring offset accurately—especially with a tire installed—can be challenging, so we recommend consulting a professional when possible.

You may find factory wheel specifications online, but always verify the information before making a purchase. Incorrect offset information can lead to expensive fitment problems.

Offset is one of the most important factors in tire fitment. Many people want a more aggressive stance or the look of a dished wheel, but moving the wheel farther outward with more negative offset often creates clearance issues. The farther the tire sticks out, the more likely it is to contact the fender, bumper, liner, or other components during steering and suspension travel. In some cases, this means you may need to choose a smaller tire diameter to avoid rubbing.

More-negative-offset wheels can also create other issues, including increased wear on steering and suspension components, changes to scrub radius and alignment behavior, reduced turning radius, and more dirt thrown down the side of the vehicle if wider fender flares are not used.

A wider tire or a specific wheel style may require a wheel with more negative offset than stock. That can be necessary for brake or steering clearance, especially with larger tires, but it is also where professional guidance, accurate measurements, and hands-on fitment experience become especially valuable.

Still wondering, "what size off-road tire will fit your vehicle?" We do not want to overcomplicate the process—we want you to understand what goes into making a smart wheel-and-tire investment. Too often, customers come to us after purchasing expensive packages elsewhere, only to discover they have rubbing, clearance, handling, or fitment issues.

We prefer to start by understanding the look the customer wants and the wheel style they have in mind. Whenever possible, we also like to inspect the vehicle in person so we can provide the most informed recommendation for wheels and tires.

Other factors matter as well, including wheel and tire load ratings, lug-nut compatibility, TPMS sensors, wheel-weight placement, brake clearance, brake upgrades for oversized tires, and more. Tires are among the most important safety-related components on your vehicle, so do your research and work with experienced professionals to ensure proper fitment, product selection, and installation.

If you have any more questions about regarding what size off-road tire will fit your vehicle, please contact one of our OK4WD Pros and we'll walk you through the process.