1981 GMC Trucks C2500 Tires

The 1981 GMC Trucks C2500 uses four primary tire sizes: 7.50R16, 8.75R16.5, 9.50R16.5, and 950-16.5. The three R-designated sizes are radial fitments, while 950-16.5 is a bias-ply size. The correct one depends on the truck’s exact sub-model, including GVWR, stud configuration, and whether it is a Bonus Cab front or rear application.

That means the first step is not choosing a brand or tread style, but confirming the exact version of the truck and the wheel diameter already on it. A 16-inch wheel truck and a 16.5-inch wheel truck do not use the same tire, and GVWR-based differences matter here as well.

A 1981 GMC Trucks C2500 can use either a 16-inch or 16.5-inch rim, depending on the tire size and sub-model. The 7.50R16 fitment uses a 16-inch wheel, while 8.75R16.5, 9.50R16.5, and 950-16.5 all use 16.5-inch wheels. Rim diameter is one of the biggest fitment checkpoints on this truck.

Truck owners should verify the actual wheel diameter on the vehicle before selecting tires, especially on older pickups that may have seen wheel changes over the years. The tire size and wheel diameter have to match exactly, so a quick inspection of the wheels can prevent ordering the wrong tire family.

More than one tire size applies because the 1981 GMC Trucks C2500 was offered in several sub-model configurations. GVWR 6400 versions use radial fitments that can be tied to either 16-inch or 16.5-inch wheels, while GVWR 8600 and the Bonus Cab front and rear applications shown here use 950-16.5 bias-ply tires.

That variation makes identification more important than guesswork. Stud size, GVWR, and the actual wheel setup all help narrow the correct fitment. On a truck that has been modified, the safest approach is to compare the current wheel diameter and application before committing to any tire size.

For the 1981 GMC Trucks C2500, 950-16.5 is a bias-ply tire size. It appears on the GVWR 8600 configurations and on the Bonus Cab front and rear applications covered here. That separates it from the radial fitments on some GVWR 6400 trucks, which use 7.50R16, 8.75R16.5, or 9.50R16.5.

Bias-ply construction affects both the look and the setup, so the key practical step is confirming that the truck actually uses the 950-16.5 application and 16.5-inch wheels. Owners trying to preserve a traditional truck presentation often want to stay within that same construction and size family.

The right answer depends on the exact 1981 GMC Trucks C2500 configuration. Some sub-models use radial primary sizes, while others use 950-16.5 in bias-ply construction. On this truck, the first decision is not which construction sounds better in general, but which construction belongs to the specific GVWR and wheel setup already on the vehicle.

Once the correct application is identified, the choice becomes simpler. A truck being kept close to its established heavy-duty look may stay with its bias-ply fitment, while a radial-equipped configuration should remain within its radial size family. Wheel diameter and actual wheel type should always be checked before making any construction change.

A conversion starts with confirming whether the truck’s original application is one of the 950-16.5 bias-ply sub-models or one of the radial fitments already tied to GVWR 6400 configurations. The wheel diameter, wheel width, and the actual size mounted on the truck all need to line up before any radial alternative is considered.

Clearance around the fenders and steering components also deserves attention, especially on an older work truck that may have aftermarket wheels or suspension changes. The goal is to verify the whole setup rather than assume that sharing a similar width or wheel diameter makes two tire types interchangeable.

Start by confirming that the truck is one of the 1981 GMC Trucks C2500 applications that actually uses 950-16.5, since that size is tied to specific GVWR 8600 and Bonus Cab positions. From there, compare the available bias-ply truck series, sidewall style, rim-width compatibility, and load specification tied to the tire.

The current 950-16.5 choices are both blackwall bias-ply truck tires, but they differ by series and weight. Buyers using the truck for restoration-minded presentation may focus on traditional appearance, while trucks expected to work or drive more regularly may put more emphasis on the tire’s operating role and wheel match.

The product assortment shown for the 1981 GMC Trucks C2500 centers on STA in the 950-16.5 size. That includes truck-oriented bias-ply offerings within the Traxion and Super Transport series. For a buyer working with one of the 950-16.5 applications, the brand choice is straightforward and the real comparison happens within the available STA lineup.

That kind of product range shifts the decision away from brand-versus-brand shopping and toward selecting the tire series that best suits the truck’s intended use and appearance. It is also worth checking the wheel width on the truck so the chosen 950-16.5 tire matches the wheel as well as the application.

For the 1981 GMC Trucks C2500 applications covered by the current product range, the available 950-16.5 bias-ply series are STA Traxion and STA Super Transport. Both are blackwall truck tires built around the same 16.5-inch fitment and the same load figure of 2780 at 60 psi.

Series differences matter because they help define the character of the tire within the same size family. A buyer comparing them should look at the overall truck-use intention, the wheel-width requirement, and whether the tire’s presentation suits a working pickup, a preserved original-style truck, or a more restoration-focused build.

A period-style 1981 GMC Trucks C2500 build starts with using the correct primary size for the exact sub-model, not simply choosing a vintage-looking tire. For the GVWR 8600 and Bonus Cab applications shown here, that means focusing on the 950-16.5 bias-ply fitment, which preserves a traditional heavy-duty truck presentation on a 16.5-inch wheel.

Once the right size family is confirmed, the choice can shift to tire series and overall appearance. Buyers pursuing exact historical accuracy should compare the truck’s own documentation, old photos, or marque-specific reference material, since a correct fitment and a period-style look are not always the same thing.

Construction changes the visual character of a restored 1981 GMC Trucks C2500 more than many buyers expect. A bias-ply truck tire such as 950-16.5 gives a more traditional heavy-duty presentation, while the radial fitments used on some GVWR 6400 trucks bring a different sidewall profile and stance within their own size families.

That matters most when the goal is to keep the truck visually consistent with its original-era equipment and wheel setup. Rather than choosing by appearance alone, confirm the truck’s actual sub-model and wheel diameter first, then decide whether maintaining the established construction helps support the restoration direction.

Yes, modifications can affect tire fitment on a 1981 GMC Trucks C2500. Aftermarket wheels, suspension changes, altered ride height, or swapped axles can all change the wheel diameter, wheel width, and available clearance. That is especially important on this truck because both 16-inch and 16.5-inch tire applications appear across the covered sub-models.

A truck that no longer carries its original wheel setup should be checked in person before any tire is selected. Looking at actual wheel diameter, steering clearance, and the space around the fenders will do more to prevent fitment mistakes than relying on model name alone.

Before road use, inspect the wheels for the correct diameter and sound condition, confirm the tires are mounted in the proper size for the truck’s application, and check inflation pressure carefully. It also helps to look over the suspension, steering components, and brake hardware so the new tires are not being installed onto a worn or unstable front end.

Collector and work-truck survivors often sit for long periods, so a broader walk-around is worthwhile. Check for rubbing at full steering lock, uneven ride height, loose wheel hardware, and any sign that the current wheel and tire package does not match the truck’s actual configuration or intended use.

950-16.5 tires on a collector 1981 GMC Trucks C2500 should be kept properly inflated, inspected regularly for cuts, bulges, cracking, and air loss, and protected from long periods of harsh sunlight or damp storage. Older trucks that are driven only occasionally benefit from routine visual checks even when tread wear is minimal.

Good maintenance also includes watching the wheel itself and the truck’s load-carrying habits. A heavy-duty bias-ply truck tire should be paired with the correct wheel and used within the truck’s intended operating range. Periodic inspections before longer drives are especially worthwhile on low-mileage vintage pickups.