The 1981 GMC Trucks C3500 sits in the square-body heavy-duty era, when one-ton pickups were expected to handle work, towing, and commercial service with straightforward mechanical durability. Tire selection on this truck starts with confirming the exact configuration, because the C3500 uses three primary bias-ply sizes: 950-16.5, 750-16, and 875-16.5. That means the real decision is not just brand, but also wheel diameter, single-rear-wheel versus dual-rear-wheel setup, and whether the truck is wearing a more highway-oriented or traction-oriented tire series. For a restoration-minded owner or a working collector truck, matching the tire to the wheel setup is the first step before choosing appearance and duty character.
Which Tire Size Is Right for The 1981 GMC Trucks C3500
The 1981 GMC Trucks C3500 uses three primary tire sizes, and the correct one depends on the truck's exact configuration. Both sub-model and wheel diameter matter here, because this fitment spans 16-inch and 16.5-inch bias-ply applications. Before choosing a tire, identify whether the truck is a front or rear application, a dual-rear-wheel setup, and which wheel diameter is actually on the vehicle.
Fit(s): (7/16 & 1/2 inch studs) Front, (7/16 & 1/2 inch studs) Rear, (9/16 inch studs) Front, (9/16 inch studs) Rear, Bonus Cab (DRW)(7/16 & 1/2 inch studs), and Bonus Cab (DRW)(9/16 inch studs)
Construction: Bias Ply|Rim: 16.5 in
950-16.5 is a vintage numeric bias-ply size in which the 9.50 designation refers to nominal section width and the 16.5 identifies the wheel diameter. On the 1981 GMC Trucks C3500, this is a bias-ply truck fitment used on several configurations, so preserving the correct wheel diameter is essential before any purchase. Available choices in this size include STA Traxion and STA Super Transport, both in blackwall form and both aimed at truck-duty use. This size makes sense when the truck retains its 16.5-inch wheel setup and the goal is staying with a heavy-duty period-style bias-ply tire.
Fit(s): (DRW)(7/16 & 1/2 inch studs) and (DRW)(9/16 inch studs)
Construction: Bias Ply|Rim: 16 in
750-16 is a vintage numeric bias-ply size, with the 7.50 indicating nominal section width and the 16 identifying the wheel diameter. For the 1981 GMC Trucks C3500, this size appears on certain dual-rear-wheel configurations, making wheel and axle setup just as important as the size itself. Product choice is broad here, with Firestone, Lester, BFGoodrich, and STA offerings across classic bias-ply, military and truck patterns, blackwall, and wide whitewall styles. This size deserves a closer look when the truck is on 16-inch wheels and the owner wants more variety in appearance or duty-focused tread character.
Fit(s): (DRW)(7/16 & 1/2 inch studs) and (DRW)(9/16 inch studs)
Construction: Bias Ply|Rim: 16.5 in
875-16.5 follows the same vintage numeric bias-ply format, using an 8.75 nominal section width on a 16.5-inch wheel. On the 1981 GMC Trucks C3500, this size is tied to certain dual-rear-wheel applications, so it should be selected only after the truck's exact wheel and configuration are confirmed. STA offers this size in blackwall truck-oriented series including Traxion and Transport Highway, giving a choice between traditional heavy-duty styles within the same basic fitment. This size is most relevant when a dually C3500 is already equipped with 16.5-inch wheels and needs a matching bias-ply replacement path.
Sub-model fitment on the 1981 GMC Trucks C3500 is not one-size-fits-all. Stud size, front or rear position, and especially dual-rear-wheel configuration can change the tire size, so identifying the exact version of the truck matters before comparing products.
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1981 GMC Trucks C3500 (7/16 & 1/2 inch studs) Front
This front application uses the 950-16.5 bias-ply size. Tire choice here centers on staying with the correct 16.5-inch wheel fitment and then choosing between available truck-oriented blackwall series.
1981 GMC Trucks C3500 (7/16 & 1/2 inch studs) Rear
This rear application also uses the 950-16.5 bias-ply size. That keeps sizing consistent front to rear for this setup, but the wheel diameter should still be confirmed before selecting among available STA truck tires.
This front configuration uses the same 950-16.5 bias-ply size. The main buying decision is whether the truck needs a more transport-oriented or traction-oriented series while keeping the original wheel diameter in mind.
This rear configuration matches the 950-16.5 bias-ply fitment used up front. With size consistency in place, product selection becomes more about tire series and intended truck use than about multiple primary sizes.
1981 GMC Trucks C3500 (DRW)(7/16 & 1/2 inch studs)
This dual-rear-wheel configuration can use either 750-16 or 875-16.5, so wheel diameter becomes the first thing to verify. Once that is settled, the buyer can compare a wider 16-inch product assortment versus the more limited 16.5-inch truck-oriented choices.
This dual-rear-wheel version also spans two possible sizes: 750-16 and 875-16.5. The correct path depends on whether the truck is on 16-inch or 16.5-inch wheels, followed by the preferred tire series and visual style within that size.
This Bonus Cab dual-rear-wheel application uses the 950-16.5 bias-ply size. Selection is straightforward once the wheel setup is confirmed, with the decision narrowing to the available blackwall STA truck series.
1981 GMC Trucks C3500 Bonus Cab (DRW)(9/16 inch studs)
This Bonus Cab dual-rear-wheel version also uses 950-16.5 in bias-ply construction. That makes the main decision less about size and more about choosing the tread character and service style that suits the truck's intended use.
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 1981 GMC Trucks C3500 Tires for Sale
Available 1981 GMC Trucks C3500 tires focus on bias-ply truck fitment, with Firestone, BFGoodrich, Lester, and STA options depending on size. Buyers can compare classic bias-ply, military and truck series, blackwall versus wide whitewall styling, and rim-width compatibility across the structured product grid.
Common questions for the 1981 GMC Trucks C3500 usually come down to identifying the correct tire size by configuration, confirming 16-inch versus 16.5-inch wheels, and choosing among bias-ply truck tires with the right appearance and duty character.
Tire Size & Fitment
What tire size fits a 1981 GMC Trucks C3500?
The 1981 GMC Trucks C3500 uses three primary bias-ply tire sizes: 950-16.5, 750-16, and 875-16.5. The correct size depends on the truck's exact configuration, because some versions use 950-16.5 while certain dual-rear-wheel applications use either 750-16 or 875-16.5.
That makes identification more important than simply choosing a heavy-duty truck tire by appearance. Check whether the truck is single- or dual-rear-wheel, confirm the front or rear application where relevant, and verify the wheel diameter already on the vehicle. A 16-inch wheel and a 16.5-inch wheel are not the same fitment, even when the truck is from the same model year.
What size rim does a 1981 GMC Trucks C3500 use?
The 1981 GMC Trucks C3500 uses both 16-inch and 16.5-inch rim diameters, depending on configuration. The 750-16 size mounts on a 16-inch wheel, while 950-16.5 and 875-16.5 use 16.5-inch wheels.
Wheel diameter is the first thing to confirm before comparing brands or tread styles. Many trucks of this age have seen wheel changes over time, and a one-ton work truck may no longer wear its original setup. Reading the wheel itself, checking the current tire size, and confirming whether the truck is a dually helps prevent choosing the right-looking tire in the wrong diameter.
Why does the 1981 GMC Trucks C3500 have more than one tire size?
The 1981 GMC Trucks C3500 has more than one tire size because fitment changes with the truck's exact setup. Standard front and rear applications commonly use 950-16.5, while certain dual-rear-wheel versions use either 750-16 or 875-16.5.
That means the tire decision starts with configuration, not just year and model name. A truck with dual rear wheels or a different wheel package can require a different diameter and section width than another C3500 from the same year. Matching the tire to the actual wheel and axle setup is the practical step that keeps the search focused on tires that belong on that truck.
Choosing the Right Tire
What should I consider when choosing a 950-16.5 tire for a 1981 GMC Trucks C3500?
Choosing a 950-16.5 tire for a 1981 GMC Trucks C3500 starts with confirming that the truck actually uses a 16.5-inch wheel and that 950-16.5 is the correct size for that configuration. In this size, available options include STA truck-oriented bias-ply tires in the Traxion and Super Transport series.
The next step is matching the tire's character to how the truck will be used and presented. A restoration-minded owner may want a traditional heavy-duty look, while a truck that still sees work may need a tread style better suited to service use. It also helps to compare the product's rim-width specification and load figure at its stated inflation pressure before making the final choice.
What sidewall styles are available for 1981 GMC Trucks C3500 tires?
Sidewall style depends on the tire size used on the 1981 GMC Trucks C3500. Blackwall is the main presentation across 950-16.5 and 875-16.5 truck applications, while 750-16 also includes wide whitewall choices alongside blackwall options.
That gives 750-16 owners the broadest appearance range, especially if the truck is being styled for a more vintage or custom look instead of a work-truck presentation. Sidewall choice should still come after confirming the correct size and wheel diameter, because appearance options do not override fitment. Once the size is settled, sidewall style becomes a useful way to match the truck's intended personality.
What brands offer tires for the 1981 GMC Trucks C3500?
Tires for the 1981 GMC Trucks C3500 are available from STA, Firestone, BFGoodrich, and Lester, depending on the size. STA covers all three primary sizes, while Firestone, BFGoodrich, and Lester appear in the 750-16 fitment with both truck-oriented and classic bias-ply choices.
Brand comparison matters most after the correct size is pinned down. Once the truck's wheel diameter and configuration are confirmed, the brand mix helps narrow the kind of tire being considered, from heavier-duty truck patterns to classic bias-ply and wide whitewall offerings. The most useful comparison is not just the name on the sidewall, but the series, sidewall style, and load-related specifications attached to that product.
Restoration & Appearance
Which tire should I choose for a period-style 1981 GMC Trucks C3500?
A period-style 1981 GMC Trucks C3500 should begin with the correct primary bias-ply size for the truck's actual configuration: 950-16.5, 750-16, or 875-16.5. Staying within the proper vintage numeric bias-ply format preserves the truck's traditional stance and visual character better than treating all one-ton GMC setups the same.
After size is confirmed, the appearance decision becomes more specific. A blackwall truck tire suits a work-oriented presentation, while 750-16 also opens the door to wide whitewall styling for a more custom or restoration-flavored look. Exact originality can vary by how a truck was equipped and used, so owners chasing highly specific authenticity should compare against marque references and surviving vehicle details.
How does tire construction affect the appearance of a restored 1981 GMC Trucks C3500?
On a restored 1981 GMC Trucks C3500, bias-ply construction plays a major role in the truck's visual impression because all primary fitments here are bias-ply truck sizes. The sidewall shape, tread presentation, and overall stance are part of what gives a square-body one-ton truck its proper heavy-duty vintage look.
Appearance is not just about whitewall versus blackwall. The right construction in the right size helps the truck look proportionate to its wheel and axle setup, especially on dually applications where wheel diameter changes the whole visual balance. For a restoration-oriented result, confirm configuration first, then choose the series and sidewall treatment that support the truck's intended era-correct feel.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1981 GMC Trucks C3500?
Yes, modifications can affect tire fitment on a 1981 GMC Trucks C3500. Wheel swaps, dually conversions, suspension changes, or aftermarket wheel widths can alter which of the truck's original bias-ply sizes makes sense and can also change clearance at the fender, steering, or rear dual setup.
A one-ton truck from this era may have been changed for work, towing, or appearance, so the current setup matters more than assumptions. Measure the actual wheel diameter, confirm wheel width, and look closely at spacing where dual wheels or steering components are involved. That extra verification is especially important when the truck could use either 16-inch or 16.5-inch tires depending on configuration.
What should I inspect before driving a 1981 GMC Trucks C3500 on new tires?
Before driving a 1981 GMC Trucks C3500 on new tires, inspect the wheels for damage, confirm lug hardware matches the wheel and stud setup, and make sure the tires are inflated appropriately for their rated load specification. It also helps to verify that each tire size matches the truck's actual wheel diameter and position.
A close walkaround matters on collector and work-era trucks because long storage and intermittent use can hide problems. Check for rubbing at full steering lock, confirm dual-wheel spacing where applicable, and look over suspension, brake, and steering components while the tires are being fitted. A short initial road test followed by a pressure and hardware recheck is a smart final step.
How should 950-16.5, 750-16, or 875-16.5 tires on a collector 1981 GMC Trucks C3500 be maintained?
Tires on a collector 1981 GMC Trucks C3500 should be maintained with regular pressure checks, visual inspections, and storage habits that limit age-related deterioration. Even if tread looks good, bias-ply tires deserve periodic checks for cracking, cuts, bulges, irregular wear, and slow air loss, especially on a truck that is driven infrequently.
Storage conditions matter almost as much as mileage on an older heavy-duty truck. Keeping the vehicle away from prolonged sunlight, moisture, and ozone sources helps protect sidewalls, and moving the truck occasionally can help avoid long-term flat spotting. Before any longer drive, recheck pressure, inspect the tread and sidewalls, and confirm that the tires still suit the truck's current wheel and load setup.
