The 1991 GMC Trucks K2500 comes from a period when three-quarter-ton 4x4 pickups were expected to do real work while still serving as everyday transportation. In Sierra, Sierra SLE, and Sierra SLX form, this truck sits squarely in the heavy-duty full-size era that valued load capacity, durability, and straightforward mechanical fitment. Tire choice centers on two 16-inch radial sizes, 225/75R16 and 245/75R16, with fitment varying by sub-model. Current options in these sizes focus on an all-terrain radial with raised white letter styling, so the real decision is confirming the correct size for the truck and matching the tire's stance, load capacity, and intended road use.
Which Tire Size Is Right for The 1991 GMC Trucks K2500
The 1991 GMC Trucks K2500 uses two primary tire sizes, and both are radial tires built for a 16-inch rim. The first step is identifying the exact sub-model, because some versions can use either 225/75R16 or 245/75R16 while the Sierra Ext. Cab uses 245/75R16. Once the sub-model is confirmed, the remaining choice is the tire's load-focused specifications, all-terrain character, and overall stance.
225/75R16 is a metric radial size in which 225 identifies the nominal section width in millimeters, 75 is the aspect ratio, and 16 is the wheel diameter in inches. On the 1991 GMC Trucks K2500, this is one of the primary 16-inch radial fitments and is used on certain Sierra, Sierra SLE, and Sierra SLX configurations. Available product selection in this size centers on a BFGoodrich All-Terrain T/A KO2 with raised white letter sidewalls. This size is worth considering when your truck is equipped for the narrower K2500 fitment and you want to stay with the proper 16-inch radial format.
Fit(s): Sierra, Sierra Ext. Cab, Sierra SLE, and Sierra SLX
Construction: Radial|Rim: 16 in
245/75R16 is a metric radial size that uses a 245-millimeter nominal section width, a 75-series profile, and a 16-inch rim. For the 1991 GMC Trucks K2500, it serves as the larger of the two primary radial fitments and appears on the Sierra Ext. Cab as well as certain Sierra, Sierra SLE, and Sierra SLX versions. Product choice in this size also centers on a BFGoodrich All-Terrain T/A KO2 with raised white letter styling. Buyers typically evaluate this size when the truck already uses the wider K2500 setup and the wheel width and overall clearance support it.
Sub-model fitment matters on the 1991 GMC Trucks K2500 because tire size is not completely uniform across the range. Some Sierra trims can use either primary size, while the Sierra Ext. Cab is tied specifically to 245/75R16, so confirming the exact truck configuration should come before choosing a tire.
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1991 GMC Trucks K2500 Sierra
The 1991 GMC Trucks K2500 Sierra can use either of the two primary 16-inch radial tire sizes. That makes wheel and current-vehicle verification especially important before choosing between the narrower 225/75R16 fitment and the wider 245/75R16 option.
The 1991 GMC Trucks K2500 Sierra Ext. Cab uses the 245/75R16 radial size. Tire selection here is more straightforward, with the main task being confirmation of the truck's existing 16-inch wheel setup and comparison of load-oriented specifications within that size.
The 1991 GMC Trucks K2500 Sierra SLE can be equipped with either 225/75R16 or 245/75R16 radial tires. Because both sizes appear within this sub-model, choosing the right tire starts with checking the truck's current wheel-and-tire combination rather than selecting by trim name alone.
The 1991 GMC Trucks K2500 Sierra SLX also spans both primary 16-inch radial sizes. That means the buyer should verify the wheel setup on the individual truck first, then compare tire width, rim-width compatibility, and intended use within the correct size.
The tire sizes listed on this page assume factory-standard vehicle configuration. The following modifications may affect tire fitment and are not reflected in this guide:
Suspension changes (lowering, lift kits, spring replacements)
Body alterations (fender modifications, custom bodywork)
If your vehicle has been modified from factory specifications, verify tire clearance before purchase.
Best 1991 GMC Trucks K2500 Tires for Sale
Available tire choices for the 1991 GMC Trucks K2500 focus on 225/75R16 and 245/75R16 radial all-terrain fitments from BFGoodrich. The product grid is most useful for comparing the KO2's raised white letter presentation, rim-width compatibility, weight, and load-capacity differences between the two sizes.
Owners of a 1991 GMC Trucks K2500 usually need clarity on which of the two 16-inch radial sizes applies, how sub-model fitment varies, and what to inspect before putting a heavy-duty pickup back on the road or changing wheel and tire setups.
Tire Size & Fitment
What tire size fits a 1991 GMC Trucks K2500?
The 1991 GMC Trucks K2500 uses two primary tire sizes: 225/75R16 and 245/75R16. Both are radial sizes built for a 16-inch wheel, and the correct one depends on the truck's exact sub-model and existing wheel-and-tire setup.
Sierra, Sierra SLE, and Sierra SLX versions can use either size, while the Sierra Ext. Cab uses 245/75R16. That means the safest starting point is checking the size already on the truck and confirming the wheel width before selecting a replacement, especially if the pickup has changed hands or has seen wheel, suspension, or trim-level changes over time.
What size rim does a 1991 GMC Trucks K2500 use?
The primary tire fitments for the 1991 GMC Trucks K2500 are both built around a 16-inch rim diameter. That applies to 225/75R16 and 245/75R16, so the wheel diameter itself remains consistent even though the truck can use two different tire widths.
Rim diameter is only one part of the fitment picture on a heavy-duty pickup. Wheel width also matters, since the 225/75R16 and 245/75R16 products use different rim-width ranges, so it is smart to confirm both the wheel diameter and the actual wheel width before changing sizes or replacing a worn set.
Why does the 1991 GMC Trucks K2500 have more than one tire size?
The 1991 GMC Trucks K2500 has more than one tire size because fitment varies within the model range. Sierra, Sierra SLE, and Sierra SLX configurations can use either 225/75R16 or 245/75R16, while the Sierra Ext. Cab uses 245/75R16.
That variation means trim name alone is not always enough to choose a tire. Checking the exact sub-model, the wheel currently on the truck, and the tire size already installed will help avoid ordering the wrong width, especially on pickups that may have been updated with different wheels during years of work, towing, or off-road use.
Choosing the Right Tire
What should I consider when choosing a 225/75R16 or 245/75R16 tire for a 1991 GMC Trucks K2500?
Start with the correct primary size for the truck, since the 1991 GMC Trucks K2500 can use either 225/75R16 or 245/75R16 depending on sub-model and setup. Both available choices are radial all-terrain tires built for 16-inch wheels, but they differ in width, weight, rim-width compatibility, and load capacity.
After size is confirmed, compare how the truck is actually used. A K2500 that sees hauling, towing, rough roads, or regular off-pavement use should be matched carefully to the tire's load specification and wheel width, while a lighter-use truck owner may focus more on maintaining the proper stance and preserving the intended driving balance.
What sidewall styles are available for 1991 GMC Trucks K2500 tires?
The available products for the 1991 GMC Trucks K2500 use an RWL sidewall, which means raised white letter styling. That sidewall treatment appears on both the 225/75R16 and 245/75R16 BFGoodrich All-Terrain T/A KO2 options.
Sidewall style affects appearance more than fitment, but it can still matter on a truck from this era. Raised white letters suit the period all-terrain look many owners want, especially on a square-body GMC pickup, while the more important technical checks remain the correct tire size, wheel width, and load-related suitability for the truck's intended work.
What tire series are available for the 1991 GMC Trucks K2500?
Current product selection for the 1991 GMC Trucks K2500 centers on the BFGoodrich All-Terrain T/A KO2 series in both primary sizes. It is a radial all-terrain offering available in 225/75R16 and 245/75R16 for the truck's 16-inch wheel fitments.
That keeps the decision focused on size and specification rather than choosing between several very different tread families. Once the correct fitment is verified, compare the KO2's rim-width range, load capacity, and weight in the applicable size so the tire matches the way the K2500 is driven, loaded, and equipped.
Restoration & Appearance
Which tire should I choose for a period-style 1991 GMC Trucks K2500?
A period-style approach starts with using the correct primary size for the truck: 225/75R16 or 245/75R16, depending on the exact K2500 configuration. Since this model uses radial construction as its primary fitment, staying with the proper 16-inch radial format preserves the truck's intended overall tire character.
Appearance then comes down to how closely the tire presentation matches the look you want from an early-1990s GMC heavy-duty pickup. The available raised white letter all-terrain style gives the truck a distinctly era-appropriate stance, but exact originality should still be checked against truck-specific references if restoration judging or detailed historical accuracy matters.
Does correct tire fitment matter for a 1991 GMC Trucks K2500 restoration?
Correct tire fitment matters on a 1991 GMC Trucks K2500 restoration because tire size has a strong effect on stance, wheel-well fill, and the overall visual balance of a heavy-duty 4x4 pickup. Using the proper 16-inch radial size also helps keep the restoration aligned with the truck's original fitment style.
The K2500 adds an extra layer of importance because more than one primary size exists within the model range. A restoration-minded owner should confirm the exact sub-model and wheel setup first, then choose the tire that supports both the truck's intended appearance and the practical needs of a three-quarter-ton pickup that may still see real road use.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1991 GMC Trucks K2500?
Yes, modifications can affect tire fitment on a 1991 GMC Trucks K2500 even when the truck still uses one of the primary sizes. Aftermarket wheels, changes in wheel width, suspension lifts, ride-height changes, or body and steering alterations can all influence how a 225/75R16 or 245/75R16 tire sits and clears.
A truck that has been changed from its original setup should be checked at full steering lock and through suspension travel before a new tire is chosen. On a K2500, that inspection is especially important because the model already spans two factory-style widths, so modifications can blur what size and wheel combination the truck should carry.
What should I inspect before driving a 1991 GMC Trucks K2500 on new tires?
Before driving a 1991 GMC Trucks K2500 on new tires, inspect the wheels for correct diameter and width, confirm the installed tire size matches the truck's fitment, and check that inflation pressure is appropriate for the tire and intended load. Lug hardware, valve stems, and visible wheel damage also deserve attention.
A road-ready inspection should also include steering clearance, suspension condition, and signs of rubbing at the fenders or inner wheelhouses. Because the K2500 is a heavy-duty truck, uneven wear, looseness in front-end parts, or old alignment issues can show up quickly after tire replacement, so a short test drive and recheck are worthwhile.
How should 225/75R16 and 245/75R16 tires on a collector 1991 GMC Trucks K2500 be maintained?
Tires on a collector-era 1991 GMC Trucks K2500 should be maintained with regular pressure checks, routine visual inspections, and attention to tread wear across the full contact patch. Even if the truck is driven only occasionally, sidewall cracking, cuts, bulges, and slow air loss should be checked before each outing.
Storage conditions matter just as much as mileage on an older pickup. Keeping the truck away from prolonged sunlight, excess heat, moisture, and ozone sources can help preserve tire condition, and moving the vehicle periodically helps avoid long-term flat spotting on a truck that carries the weight and heavy-duty hardware of a K2500.
