The 1991 GMC Trucks K3500 sits in the era when one-ton pickups were expected to handle serious work, from towing and hauling to year-round four-wheel-drive use. Buyers looking after one today often want the same combination of capability, stance, and dependable road manners that made these heavy-duty GMC trucks so useful in the first place. Tire fitment centers on two 16-inch radial sizes, 225/75R16 and 245/75R16, so the main question is confirming which setup is on the truck rather than choosing between bias-ply and radial construction. Available options keep the focus on LT-rated all-terrain capability, raised white letter appearance, wheel compatibility, and overall clearance.
Which Tire Size Is Right for The 1991 GMC Trucks K3500
The 1991 GMC Trucks K3500 uses two primary tire sizes, and both are radial tires built for 16-inch wheels. Because Sierra, Sierra SLE, and Sierra SLX models can use either size, the first step is confirming which wheel and tire setup is actually on the truck. Once that is settled, the decision becomes choosing the right LT radial for load capacity, rim-width compatibility, and the look and use you want.
245/75R16 follows the same metric radial sizing system, with a 245 millimeter nominal section width, a 75-series profile, radial construction, and a 16-inch rim diameter. For the 1991 GMC Trucks K3500, it represents the wider of the two primary radial fitments and still stays within the truck's original 16-inch wheel family. The available tire in this size is also a BFGoodrich All-Terrain T/A KO2 with raised white letter styling. This size is worth checking when the truck is set up for the broader footprint, provided wheel width and body clearance remain appropriate.
Tire fitment is straightforward across the covered 1991 GMC Trucks K3500 sub-models because Sierra, Sierra SLE, and Sierra SLX all use the same two radial size choices. The important check is not trim level alone, but which 16-inch wheel and tire combination is actually installed on the truck.
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1991 GMC Trucks K3500 Sierra
The 1991 GMC Trucks K3500 Sierra can use either of the two primary 16-inch radial tire sizes. That means tire selection starts with confirming the truck's current wheel and size setup, then choosing the LT radial option that best matches its load demands and intended use.
The 1991 GMC Trucks K3500 Sierra SLE shares the same radial tire fitment choices as the other covered K3500 sub-models. Buyers should verify whether the truck is running the 225-width or 245-width setup before comparing rim-width compatibility, load capacity, and overall tire presentation.
The 1991 GMC Trucks K3500 Sierra SLX also falls within the same two-size 16-inch radial fitment range. That keeps the decision centered on the actual wheel and tire combination on the truck, along with the level of hauling, towing, and general road use expected from it.
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 K3500 Tires for Sale
Available 1991 GMC Trucks K3500 tire choices focus on 225/75R16 and 245/75R16 LT radial fitments from BFGoodrich in the All-Terrain T/A KO2 series. The main comparison points are size, raised white letter sidewall appearance, rim-width range, weight, and load capacity.
These FAQs focus on the 1991 GMC Trucks K3500's two 16-inch radial tire sizes, how they relate to the Sierra sub-models, and what to check for wheel fitment, load use, appearance, and road-ready condition.
Tire Size & Fitment
What tire size fits a 1991 GMC Trucks K3500?
The 1991 GMC Trucks K3500 uses two primary tire sizes: 225/75R16 and 245/75R16. Both are radial tires designed for 16-inch wheels, and both appear across the Sierra, Sierra SLE, and Sierra SLX sub-models.
That means the key fitment step is confirming which size is actually on the truck now, or which wheel setup the truck is meant to use. Check the wheel diameter, current tire markings, and wheel width before choosing between the two sizes, especially if the truck has had wheel, suspension, or body changes over the years.
What size rim does a 1991 GMC Trucks K3500 use?
The primary tire fitments for the 1991 GMC Trucks K3500 are built around a 16-inch rim diameter. Both 225/75R16 and 245/75R16 use that same wheel diameter, so the difference between them is not the rim size but the tire's width and overall proportions.
Rim diameter is only part of the fitment picture on a heavy-duty truck like a K3500. Wheel width also matters, particularly because the available 225/75R16 and 245/75R16 products call for different rim-width ranges, so it is worth checking the actual wheels on the truck before selecting a replacement tire.
Do all 1991 GMC Trucks K3500 sub-models use the same tire size?
Sierra, Sierra SLE, and Sierra SLX versions of the 1991 GMC Trucks K3500 share the same two tire size choices: 225/75R16 and 245/75R16. That means trim level alone does not narrow the truck down to one single primary size.
Because the sub-models overlap in tire fitment, owners should verify the actual wheel and tire combination on the truck instead of relying on the badge. Looking at the existing tire sidewall, measuring wheel width, and checking for any past modifications will do more to prevent a fitment mistake than trim identification by itself.
Choosing the Right Tire
What should I consider when choosing a 225/75R16 or 245/75R16 tire for a 1991 GMC Trucks K3500?
Start with the correct size for the truck's current wheel setup, then compare construction, load capacity, and rim-width compatibility. On the 1991 GMC Trucks K3500, both primary sizes are radial 16-inch fitments, but the available 225/75R16 and 245/75R16 options carry different load figures and call for different wheel-width ranges.
A one-ton truck places more importance on practical fitment than appearance alone. Think about how the K3500 is used, whether for hauling, towing, or general driving, and check that the selected tire matches the wheel width, leaves proper clearance, and supports the kind of service the truck is expected to handle.
What sidewall styles are available for 1991 GMC Trucks K3500 tires?
The available products for the 1991 GMC Trucks K3500 use an RWL sidewall, meaning raised white letters. That gives the truck a more traditional light-truck appearance than a plain blackwall and suits the all-terrain character of the tire options offered in these two sizes.
Sidewall style does not change the basic fitment, but it does affect the truck's presentation. Raised white letters can look especially appropriate on a working-era 4x4 pickup, so the decision becomes whether that appearance matches the truck's overall finish, wheel style, and the balance you want between utility and period-flavored visual character.
What brands offer tires for the 1991 GMC Trucks K3500?
The available tire options for the 1991 GMC Trucks K3500 are from BFGoodrich. In both 225/75R16 and 245/75R16, the tire series offered is the All-Terrain T/A KO2, which keeps the brand and tread-family choice straightforward for this truck.
With a single brand and tire series represented, the main comparison is between the two sizes rather than between multiple manufacturers. Focus on the truck's actual wheel setup, the load rating tied to each size, and the intended use of the vehicle so the selected tire matches both fitment and the truck's workload.
Restoration & Appearance
Which tire should I choose for a period-style 1991 GMC Trucks K3500?
A period-style choice for a 1991 GMC Trucks K3500 starts with using one of its proper 16-inch radial sizes, either 225/75R16 or 245/75R16, depending on the truck's wheel setup. Staying within the correct size family preserves the truck's intended stance and keeps the overall look closer to the way a one-ton GMC from this era should present.
Appearance should still be balanced with real fitment and use. A K3500 often carries work-truck expectations, so the right period-style tire is not just about looks but also about matching wheel width, maintaining clearance, and selecting a load-capable tire that suits how the truck will actually be driven.
How does tire construction affect the appearance of a restored 1991 GMC Trucks K3500?
Tire construction is simple on this truck because the primary fitments are radial, not bias-ply. That means a restored 1991 GMC Trucks K3500 can maintain the era-appropriate look of a late-model heavy-duty pickup without needing to choose between vintage bias-ply styling and modern radial construction.
The visual difference will come more from size and sidewall treatment than from construction type. Choosing the correct 225/75R16 or 245/75R16 fitment and deciding whether raised white letters suit the truck's finish will have more effect on its presentation than trying to chase a different construction style.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1991 GMC Trucks K3500?
Yes, modifications can affect tire fitment on a 1991 GMC Trucks K3500 even when the tire size itself is one of the correct primary options. Changes such as aftermarket wheels, different wheel widths, altered offset, suspension lifts, lowering, or body trimming can all influence how 225/75R16 or 245/75R16 tires sit on the truck.
A truck that has been changed from stock should be checked carefully before replacement tires are chosen. Confirm the wheel diameter and width, inspect steering and fender clearance at full lock and full suspension movement, and make sure the tire selected still suits the vehicle's carrying and towing demands.
What should I inspect before driving a 1991 GMC Trucks K3500 on new tires?
Before putting a 1991 GMC Trucks K3500 back into regular use on new tires, inspect the wheels for damage, verify that the tire size matches the wheel setup, and set pressure according to the tire's service needs. It is also smart to check lug hardware, valve stems, suspension wear, and any signs of rubbing.
A heavy-duty 4x4 truck can hide fitment issues until it is loaded, turned sharply, or driven at speed. After installation, look for adequate clearance, recheck inflation, and pay attention to vibration, pull, or uneven contact that could point to alignment, wheel, or suspension problems.
How should 225/75R16 and 245/75R16 tires on a collector 1991 GMC Trucks K3500 be maintained?
Collector-use tires on a 1991 GMC Trucks K3500 should be maintained with regular pressure checks, visual inspections, and careful storage habits. Watch for cracking, cuts, bulges, uneven tread wear, and slow air loss, especially on a truck that spends long periods parked between drives or events.
Even a low-mileage K3500 can develop tire problems from age, sunlight, heat, and long static loading. Moving the truck occasionally, storing it away from moisture and ozone sources, and checking the tires before any longer drive will do more for safe use than tread depth alone on an older collector pickup.
