GMC C/K Pickup Tires

The GMC C/K Pickup used 17 tire sizes across 1971 to 1979: 700-15, G78-15, L78-15, H78-15, 875-16.5, 950-16.5, 750-16, 650-16, 700-16, LR78-15, 800-16.5, 10-16.5, GR78-15, HR78-15, 9.50-19.5, 8.75R16.5, 8.75-16, and 10-15. The 15-inch group includes 700-15, G78-15, H78-15, L78-15, LR78-15, GR78-15, HR78-15, and 10-15; the 16-inch group includes 650-16, 700-16, 750-16, and 8.75-16; the 16.5-inch group includes 800-16.5, 875-16.5, 950-16.5, 10-16.5, and 8.75R16.5; 9.50-19.5 fits 19.5-inch wheels.

The practical step is to identify the truck’s exact model year and then verify the wheel diameter on the truck itself, because GMC C/K Pickup fitments overlap heavily across the decade. Two trucks from the same year can still require different sizes if one carries 15-inch passenger-type wheels and another uses 16-inch, 16.5-inch, or 19.5-inch truck wheels.

A 700-15 tire for a GMC C/K Pickup is an older numeric size in which 700 refers to a nominal section width of about 7.00 inches and 15 refers to the rim diameter. Within this model line, 700-15 appears from 1971 through 1979 and all listed products for that size are bias-ply designs. The size code is straightforward compared with later alphanumeric and radial-style codes, but it still needs to be matched to the correct wheel diameter.

That means a GMC C/K Pickup wearing 15-inch wheels could use 700-15 only if the truck’s original size falls in that part of the fitment range, not simply because the wheel diameter matches. It is best to compare the sidewall marking on the existing tire, check the wheel size, and then decide whether a passenger-style bias-ply or a heavier truck-service tread pattern makes more sense for the truck’s use.

A 1978 GMC C/K Pickup has 14 tire sizes listed because the C/K line covered several wheel diameters and duty levels within the same model year. That year includes 15-inch, 16-inch, 16.5-inch, and 19.5-inch fitments, with both bias-ply and radial-style sizes appearing in the 15-inch and 16.5-inch groups. The variation is not a typo or duplication issue; it reflects how broadly the pickup range was configured.

The useful takeaway is that year alone is not enough for a 1978 GMC C/K Pickup. Check the actual wheel diameter first, then compare the size stamped on the current tire or verify the truck’s specific payload and wheel setup before choosing among GR78-15, HR78-15, LR78-15, 10-15, 650-16, 750-16, 8.75-16, 875-16.5, 950-16.5, 8.75R16.5, 10-16.5, or 9.50-19.5.

The GMC C/K Pickup used four rim diameters across this range: 15 inches, 16 inches, 16.5 inches, and 19.5 inches. Fifteen-inch sizes include 700-15, G78-15, H78-15, L78-15, LR78-15, GR78-15, HR78-15, and 10-15. Sixteen-inch sizes include 650-16, 700-16, 750-16, and 8.75-16; 16.5-inch sizes include 800-16.5, 875-16.5, 950-16.5, 10-16.5, and 8.75R16.5; 9.50-19.5 is for 19.5-inch wheels.

Wheel diameter is the first check because several of these size families look similar at a glance, especially 16-inch versus 16.5-inch truck tires. On a GMC C/K Pickup, those wheels are not interchangeable, so verify the stamping on the wheel or the size molded into the current tire before deciding whether a given tire belongs on the truck.

A 1975 GMC C/K Pickup can use multiple sizes, including 700-15, G78-15, H78-15, L78-15, LR78-15, 700-16, 750-16, 800-16.5, 875-16.5, 950-16.5, and 10-16.5. The correct one depends first on wheel diameter and then on how the truck was equipped within the C/K range. A 15-inch, 16-inch, or 16.5-inch wheel immediately narrows the correct family of sizes.

Start by reading the existing sidewall size if the truck still has an older-style tire on it, then compare that with the wheel diameter and general use of the truck. A half-ton GMC C/K Pickup with passenger-oriented wheels may point you toward a different fitment than a heavier truck wearing 16-inch or 16.5-inch commercial wheels, even within the same 1975 model year.

GMC C/K Pickup tires in this range are available in Blackwall, Wide Whitewall, Narrow Whitewall, and Dual-White-Stripe sidewall styles. The broadest decorative variety appears in several 15-inch and 16-inch bias-ply sizes such as 700-15, 650-16, 700-16, 750-16, and L78-15. Many of the heavier truck-duty 16-inch and 16.5-inch sizes are offered only as blackwalls, which is consistent with their work-oriented character.

That gives restorers and drivers different paths depending on the truck. A more passenger-trimmed or custom-restored GMC C/K Pickup may suit a whitewall or stripe sidewall, while a utility, farm, or heavy-duty build often looks more natural on blackwall truck tread. Choose the sidewall style after the correct size and wheel diameter are settled, not before.

Brands represented for GMC C/K Pickup tire sizes include Firestone, BFGoodrich, STA, Coker Classic, Lester, Garfield, Goodyear, Tornel, Avon, and Excelsior. Some brands appear mainly in passenger-style bias-ply sizes, while others are concentrated in truck-duty and traction patterns. Firestone, BFGoodrich, STA, and Coker Classic account for much of the coverage across the main 15-inch and 16-inch size groups.

Brand choice should come after fitment choice on a GMC C/K Pickup. Once the size and wheel diameter are confirmed, compare the available brands by sidewall style, tread character, and whether the truck is being restored for period appearance, used as a light road truck, or kept in a heavier-duty commercial or off-road presentation.

GMC C/K Pickup tire offerings span several distinct series, including Firestone Classic Bias Ply, Silvertown Classic Bias Ply, Coker Classic Bias Ply, Lester Classic Bias Ply, Deluxe All-Weather, Firestone Classic Military, STA Classic Military, Military NDT, Super Traxion, Traxion, Super Transport, Transport, Transport Highway, Tornel Classic Truck, Tornel Light Truck, Traction Mileage, Firestone Classic Truck, and Wide Oval Radial. Those series differ in construction approach and intended character, ranging from passenger-style classic bias-ply tires to military tread patterns, highway truck casings, and a bias-look radial option. The result is a much wider mix than most single-model tire pages carry.

For a GMC C/K Pickup, series choice should reflect how the truck will actually be used and presented. A restored street truck may benefit from a classic bias-ply passenger series, while a work-focused or military-style build may be better suited to an NDT, NDCC, traction, or highway truck pattern. If the goal is later-period drivability with vintage appearance, the radial-look LR78-15 option may be the most relevant comparison point.

A GMC C/K Pickup should be stored on a clean, dry surface away from direct sunlight, ozone sources, and standing moisture. Tire pressure should be kept at an appropriate maintenance level for the fitted tire, and the truck should not sit for long periods with obviously underinflated tires. Long stationary storage is harder on collector tires than regular gentle movement.

If the GMC C/K Pickup will be parked for extended stretches, roll it occasionally to change the contact patch or use suitable vehicle supports so the full weight is not always resting in one place. That helps reduce flat spotting and sidewall stress, especially on bias-ply truck tires with stiff carcasses and on seldom-driven restored trucks.

Tires on a GMC C/K Pickup should be inspected before each meaningful drive and more thoroughly several times a year, even if the truck sees very little mileage. Look for pressure loss, weather checking, tread separation signs, uneven wear, valve stem aging, and any cracking around bead or sidewall areas. Collector trucks often age their tires out long before they wear them out.

Inspection matters even more when a GMC C/K Pickup uses older-style bias-ply truck tires or has been stored indoors for long periods and appears cosmetically sound. A visual check, pressure check, and occasional wheel-off inspection are sensible habits, especially if the truck carries heavy-duty 16-inch, 16.5-inch, or 19.5-inch tires that may have seen intermittent service over many years.

A GMC C/K Pickup tire should be replaced when age, cracking, impact damage, distortion, irregular wear, or casing deterioration raises concern, even if the tread depth still looks usable. Collector vehicles frequently retain tread because they are driven sparingly, but age-related failure is still the larger issue. Any tire with visible structural change deserves immediate evaluation before further road use.

That guideline is especially important on a GMC C/K Pickup because many of these sizes serve trucks that can carry meaningful weight. Tread depth alone does not make an old tire roadworthy. If the truck has an older spare or a long-stored set that appears unused, treat it cautiously and inspect it with the same seriousness you would apply to the four tires on the ground.

The GMC C/K Pickup was fitted across this period with a broad range of sizes and tire types rather than one universal original tire. Sizes include numeric bias-ply truck sizes, alphanumeric bias-ply passenger sizes, and later radial-style sizes such as LR78-15, GR78-15, and HR78-15. Available series in the replacement market include classic bias-ply passenger lines, military-style tread families, transport and highway truck lines, and a radial-look offering.

For restoration accuracy, the best approach is to match the specific year, wheel diameter, and intended trim or duty level of the GMC C/K Pickup rather than assuming one tire fits the whole generation. Factory literature, original tire placards, and model-specific GMC truck references are the right places to confirm whether your truck originally wore a passenger-style whitewall, a blackwall truck tire, or a heavier-duty commercial tread.

Correct tire fitment can absolutely affect how a GMC C/K Pickup is judged and perceived, especially when the truck is restored to a period-specific standard. Size, sidewall style, and overall tire character all influence whether the truck reads as authentic for its trim level and intended use. A wide whitewall passenger tire and a blackwall commercial traction tire send very different visual signals even when both physically fit.

For a GMC C/K Pickup headed to shows or marque-based judging, it is wise to align the tire not only with the wheel diameter but also with the truck’s original presentation. Marque clubs, factory sales literature, and survivor trucks can help determine whether a given restoration should lean toward passenger-style bias-ply appearance, truck-duty tread, or a later radial-style look.

Correct sidewall style for a GMC C/K Pickup restoration depends on the truck’s trim, wheel size, and the character you are trying to recreate. The available choices here include blackwall, wide whitewall, narrow whitewall, and dual-white-stripe, but blackwall dominates the heavier-duty truck sizes while decorative sidewalls are more common in several 15-inch and 16-inch passenger-style bias-ply offerings. That split mirrors the difference between work-truck and more dressed-up street presentation.

A restored GMC C/K Pickup built as a plain working truck will often look most convincing on a blackwall truck tread, especially in the larger-duty wheel sizes. A custom, upscale, or passenger-trimmed build may suit one of the whitewall or stripe options better. Sidewall style should support the truck’s period appearance, not fight against it.

These tires can be appropriate for public-road use on a GMC C/K Pickup when the exact size matches the wheel, the tire is in sound condition, and the truck’s suspension, steering, and brakes are also in proper order. The available range includes passenger-style bias-ply tires, truck-duty bias-ply tires, and a radial-look option, each of which will behave differently on the road. Safe use depends on matching the tire to the truck’s actual wheel and service role.

A GMC C/K Pickup with 16-inch, 16.5-inch, or 19.5-inch commercial-type wheels should be treated especially carefully, because those applications often imply heavier loads and stiffer tire designs. Before road use, verify pressure, condition, wheel compatibility, and age, then drive within the limits of both the tire construction and the truck’s original chassis design.

Before driving a GMC C/K Pickup, check tire pressure, sidewall condition, tread integrity, wheel diameter correctness, lug torque, valve stems, and any signs of cracking or separation. On this model line, confirming the wheel diameter is especially important because similar-looking sizes may fit 15-inch, 16-inch, 16.5-inch, or 19.5-inch wheels. The truck should also be checked for steering play, brake function, and suspension issues that can exaggerate tire behavior.

That pre-drive routine matters because a GMC C/K Pickup can wear anything from a passenger-style 15-inch tire to a heavy-duty truck tire, and each setup places different demands on the vehicle. A short inspection before every drive is far easier than discovering an age-related or fitment-related issue once the truck is moving at road speed.

Appropriate speed for a GMC C/K Pickup on original-style tires depends on the exact size, construction, condition, and the truck’s overall mechanical health. Bias-ply tires, especially truck-service tread patterns, generally call for a more measured driving style than a modern highway tire, while the radial-look LR78-15 may feel different on the road than a traditional bias-ply option. No vintage-style tire should be treated as an excuse to ignore the limits of an older truck chassis.

The sensible approach with a GMC C/K Pickup is to build speed gradually, monitor how the truck tracks and brakes, and keep driving conservative if the truck wears period-style bias-ply tires. If the truck is newly restored or newly fitted with unfamiliar sizes, use short test drives first and reserve sustained higher-speed travel for situations where the tires, wheels, and chassis have all proven stable.