Should You Stick with the Stock Diameter When Upgrading Your Off-Road Tires?

• January 2, 2023
• Story By
  Andy Carter

Whenever an off-road enthusiast gets his or her hands on a new project, the first temptation is to start with a lift and tires. We can all agree that increasing the height of a vehicle does so much to better off-road performance, with benefits like increased ground clearance and improved approach and departure angles, to the simple fact that aesthetically, lifted vehicles look cool.

But like any modifications to a stock system, the benefits can be overshadowed by the sacrifices made to the practical, daily duties of a vehicle. There are a few things to consider when choosing a larger size tire for your off-road truck, SUV, or CUV.

Bigger Tires Mean Lower MPGs

One of the biggest complaints that we see from newcomers to the off-road community is the loss of efficiency for on-road commuting that comes from specializing a vehicle for off-road performance. Generally, larger diameter tires are not only heavier, but also have a higher rolling resistance than smaller tires which means they require more effort to get them rolling— meaning your engine is working harder and consuming more fuel.

While that’s a worthwhile trade-off when climbing boulders, spending more money to drive to the office on a Tuesday can get old fast.

Bigger Tires Mean Less Towing Capacity

In the same way that larger diameter tires lowers the efficiency of the engine, the same thing happens to a vehicle’s towing capacity (unless extensive modifications are made to the drivetrain).

If you want to get a rough gauge on the amount that larger diameter tires will decrease your towing capability, find the percentage of diameter increase between your old and new tires by using a wheel size calculator. Your vehicle’s towing capacity will be decreased by that same percentage—unless other modifications are made to the vehicle to compensate.

Bigger Tires Might Not Fit

While this may seem obvious to veterans in the off-road community, newcomers can underestimate the modifications needed to fit larger diameter tires. Besides the obvious changes like suspension lifts, owners may need to do something as minor as trimming a plastic mudflap, or as major as bending or bashing metal bodywork to avoid contact with the tire. Some of these changes may be reversible, and some may not.

Also, trying to identify exactly what setup will rub and what will not can be confusing given the infinite number of variables between wheel specifications, vehicle height, and tire choice between different setups of seemingly identical vehicles.

Additionally, some newer or higher end vehicles may have an adjustable suspension that needs to be accounted for when choosing tire sizes. One example is a Lexus LX570 which has a hydraulic suspension that has five inches of adjustability whether the vehicle is stopped, at highway speeds, or when the transfer case is in low range. In order to maintain full use of that OEM system without modification, it's important to stick with the manufacturer’s recommended tire size.

More Bang for Your Buck

If you have a vehicle that is already off-road capable, and you plan to stay within the limits set forth by the manufacturer, upgrading your stock tires with more aggressive tire of the same dimensions can be an effective way to extract more performance from your otherwise stock vehicle.

Our LX570 came stock with street tires that were geared towards comfort and on-road longevity. Knowing that we’d be spending a moderate amount of time riding off-road trails, we installed a set of factory-sized Nitto Ridge Grappler hybrid terrain tires.

Nitto offers an entire line of enthusiast-spec tires that range from a crossover-terrain design for today’s adventure-ready crossovers, to an extreme mud-terrain design that can contend with the most difficult terrain.

We Love Off-Road Builds, But Be Realistic About Your Vehicle Use

These stock-size tire recommendations aren’t meant to discourage anyone from modifying their off-road truck or SUV in a way that includes larger diameter tires. Serious off-roading demands extensive changes to the entire suspension setup. But for those that have a vehicle that spends most of its time on-road, or the project is under a strict budget, considering a stock size off-road tire upgrade can offer some serious bang for your buck.