What’s in a Name? – Tires Designed for Specific Truck Applications

The original tires installed on GM vehicles are designed and tested for specific vehicle applications. Full-size trucks feature a variety of different tires that are designed to perform under all types of conditions and applications, including carrying heavy loads, pulling additional weight, and delivering traction on varying types of terrain. (Fig. 5) These features cannot be identified by simply looking at the tire tread or the name of the tire.


Fig. 5


HT Does Not Mean Highway Tire

For example, some 2019-2021 Silverado 1500 and Sierra 1500 models are equipped with Goodyear Wrangler Fortitude HT tires (RPO XCK). (Fig. 6, Goodyear image) These are all-terrain tires that are designed for a specific application. However, the tread of these tires is not as aggressive as some all-terrain tires installed on other models with Trail Boss or AT4 packages. In addition, the HT may be mistaken to stand for “Highway Tire.” The HT is simply a name or model designation of the tire. It does not identify the features of the tire.

The Goodyear Wrangle Fortitude HT tires should not be replaced on a vehicle based on their appearance. If the RPO of the tire matches the tire model, the correct tires are installed on the vehicle.


Fig. 6


Tire Specifications for Model Packages

There are two tires that are available as standard equipment on Silverado and Sierra trucks equipped with the Off-Road (2-inch lift) Suspension (RPO Z7X). These are the Goodyear Wrangler Fortitude HT tire (RPO XCK) and the Goodyear Duratrac tire (RPO RCP). Since the Duratrac tire (Fig. 7, Goodyear image) is more aggressively styled, it may appear to be more of an “off road” tire than the Wrangler Fortitude HT tire.


Fig. 7


The RPO XCK tire provides excellent traction and ride quality on all surfaces, including wet and dry pavement, snow and ice. The RPO RCP tire is designed for off-road driving conditions, which also may result in additional road noise on paved surfaces. When installing new tires, it’s important to remind customers that any tire with an aggressive tread is likely to have additional on-road noise and less ride quality.

TIP: Vehicles equipped with the Off-Road Suspension (RPO Z7X) or the Enhanced Towing Performance Package (RPO NHT) can only use the Goodyear Wrangler Fortitude HT tire (RPO XCK). These tires should not be swapped for a more aggressive appearing tire, which may be overloaded when the vehicle is used to tow at the maximum capacity. An overloaded tire creates a significant safety and handling issue.


– Thanks to David MacGillis


Updated June 2, 2021

Certified Service Mobile Toolbox App Update Required by June 1
Corvette Brake Service Tips

One Comment

  1. Rich Sidor says:

    May want to edit the tip, you can’t get both Z7X and NHT together.

Leave a Reply

Your email address will not be published.