The 1978 Jeep Truck Truck J-20 sits in the era when Jeep pickups were built to do real work, with heavy-duty configurations that appeal today to restorers, farm-truck owners, and vintage 4x4 enthusiasts who still expect useful capability. Tire choice on this truck is especially fitment-driven because the J-20 uses multiple bias-ply sizes, including 750-16, 800-16.5, 875-16.5, and 950-16.5, depending on GVWR configuration. Available options range from highway-oriented truck tires to traction-focused designs, mostly in blackwall form, with 750-16 also offering more traditional bias-ply styling choices. The right selection starts with confirming the exact GVWR setup and wheel diameter before choosing the tire style that suits restoration appearance or working use.
Which Tire Size Is Right for The 1978 Jeep Truck Truck J-20
The 1978 Jeep Truck Truck J-20 uses four primary tire sizes, and the right one depends on the truck's GVWR configuration and wheel diameter. This is not a one-size-fits-all J-20 application, because both 16-inch and 16.5-inch rims appear across the covered sub-models. Before choosing a tire, confirm the exact GVWR version of the truck and verify the wheels actually on it, especially if it has been changed over the years.
875-16.5 is a numeric bias-ply size, meaning the 8.75 figure reflects the nominal section width class and 16.5 is the rim diameter. On the 1978 Jeep Truck Truck J-20, this size belongs to specific GVWR applications, so it should not be chosen simply because it is close to another J-20 tire size. Available products include STA Traxion and STA Transport Highway in blackwall form, both aligned with truck-use styling and bias-ply construction. This size is worth considering when the truck retains the correct 16.5-inch wheel equipment and the goal is to match the intended heavy-duty fitment rather than substitute across configurations.
Sub-model fitment on the 1978 Jeep Truck Truck J-20 varies by GVWR, and some versions share a size while others allow more than one primary tire size. Checking the exact GVWR configuration matters because it determines whether the truck uses a 16-inch or 16.5-inch wheel setup and which bias-ply sizes belong on it.
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1978 Jeep Truck Truck J-20 (GVWR 6500 & 6800)
The 1978 Jeep Truck Truck J-20 (GVWR 6500 & 6800) uses 16.5-inch bias-ply fitments, with tire choice centered on selecting the correct size within that wheel diameter. That makes wheel verification especially important before comparing tread style or truck-duty tire series.
The 1978 Jeep Truck Truck J-20 (GVWR 7200) spans both 16-inch and 16.5-inch bias-ply fitments, so this is one of the configurations where wheel diameter must be confirmed first. After that, the choice becomes whether the truck is being kept in a more work-oriented truck style or a more restoration-oriented appearance.
The 1978 Jeep Truck Truck J-20 (GVWR 7600) also uses more than one primary bias-ply size across 16-inch and 16.5-inch wheels. Tire selection starts with confirming the actual wheel setup on the truck, then narrowing the choice by intended use and available tire series.
The 1978 Jeep Truck Truck J-20 (GVWR 8000) can use either a 16-inch or 16.5-inch bias-ply fitment, depending on wheel equipment. Choosing correctly means matching the tire to the truck's actual rim diameter first, then comparing the available heavy-duty truck tire options in that size.
The 1978 Jeep Truck Truck J-20 (GVWR 8400) shares the same two-size pattern seen on other heavier GVWR versions, with fitment tied to either 16-inch or 16.5-inch wheels. That makes the tire decision less about brand preference at first and more about verifying which wheel diameter the truck is wearing today.
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 1978 Jeep Truck Truck J-20 Tires for Sale
Available 1978 Jeep Truck Truck J-20 tires are all bias-ply and center on truck-duty lines from STA, with 750-16 adding Firestone, BFGoodrich, and Lester choices. Buyers can compare blackwall and wide whitewall styles, highway and traction-oriented series, and rim-width specifications where they are stated.
Owners usually need to sort out J-20 tire size by GVWR and wheel diameter first, then compare bias-ply construction, truck-oriented tread series, sidewall style, and basic road-use checks before putting an older truck back into service.
Tire Size & Fitment
What tire size fits a 1978 Jeep Truck Truck J-20?
The 1978 Jeep Truck Truck J-20 does not use a single tire size across every configuration. Primary sizes include 800-16.5, 950-16.5, 750-16, and 875-16.5, all in bias-ply construction, with the exact fitment tied to the truck's GVWR version and wheel diameter.
That means the first step is identifying the truck's exact GVWR configuration and confirming whether it has 16-inch or 16.5-inch wheels. Many older trucks have had wheels changed over time, so the size that belongs on one J-20 may not be the right choice for another truck that looks similar.
What size rim does a 1978 Jeep Truck Truck J-20 use?
A 1978 Jeep Truck Truck J-20 can use either a 16-inch or a 16.5-inch rim, depending on the specific GVWR-rated configuration and tire size. The covered primary sizes split across those two diameters rather than sharing one common wheel size throughout the range.
Rim diameter needs to be verified before ordering tires because a 16-inch tire and a 16.5-inch tire are not interchangeable. It is also worth checking wheel width against the tire being considered, especially on trucks that may have received replacement steel wheels or later aftermarket wheel swaps.
Why does the 1978 Jeep Truck Truck J-20 have more than one tire size?
The 1978 Jeep Truck Truck J-20 spans several GVWR-based configurations, and those heavier-duty versions do not all use the same tire size or even the same rim diameter. That is why the J-20 appears with multiple primary bias-ply sizes instead of one uniform fitment across the model line.
For the owner, this means the truck's exact rating matters more than the badge on the fender alone. A careful match between GVWR, wheel diameter, and the tire size already on the truck helps avoid choosing a tire that belongs to a different J-20 configuration.
Choosing the Right Tire
What should I consider when choosing a tire for a 1978 Jeep Truck Truck J-20?
Start with the correct primary tire size for the truck's GVWR configuration and make sure the wheel diameter matches it. On a 1978 Jeep Truck Truck J-20, that may mean sorting between 16-inch and 16.5-inch wheels before comparing tread pattern, rim-width compatibility, construction details, or load figures tied to specific products.
After the fitment basics are settled, choose based on how the truck will be used and how it should look. Some J-20 owners want a truck-duty blackwall tire with a work-oriented tread, while others looking at 750-16 may prefer a more traditional bias-ply appearance or wide whitewall presentation.
What sidewall styles are available for 1978 Jeep Truck Truck J-20 tires?
Most 1978 Jeep Truck Truck J-20 tire options are blackwall truck tires, which suit the model's heavy-duty pickup character. In 750-16, there are also wide whitewall choices, giving that size a noticeably broader appearance range than the 16.5-inch truck fitments.
Sidewall choice should follow the truck's purpose and presentation. A blackwall usually fits a utility-minded or work-truck look, while a wide whitewall creates a more restoration-oriented visual statement. Either way, appearance comes after making sure the tire is the correct size for the truck's actual wheel setup.
What brands offer tires for the 1978 Jeep Truck Truck J-20?
Tires for the 1978 Jeep Truck Truck J-20 come from STA across all four primary sizes, with additional 750-16 options from Firestone, BFGoodrich, and Lester. Brand variety is strongest in 750-16, while the 16.5-inch truck sizes are centered on STA heavy-duty bias-ply offerings.
Brand choice should be considered alongside size, series, sidewall style, and intended use rather than by name alone. On this truck, some sizes emphasize work-oriented traction or highway use, while 750-16 also gives more room to balance truck function with a more traditional collector-truck appearance.
Restoration & Appearance
Which tire should I choose for a period-style 1978 Jeep Truck Truck J-20?
A period-style choice for a 1978 Jeep Truck Truck J-20 starts with the correct primary bias-ply size for its GVWR configuration and wheel diameter. From there, truck-oriented blackwall tires such as the STA, Firestone, and other bias-ply offerings align more naturally with the J-20's late-1970s heavy-duty pickup character.
Appearance still needs to be balanced against how the truck will be used. A utility-focused restoration may lean toward a blackwall truck tread, while some 750-16 applications can take a different visual direction. When exact originality matters, compare the tire choice with marque references or period vehicle documentation.
How does tire construction affect the appearance of a restored 1978 Jeep Truck Truck J-20?
On the 1978 Jeep Truck Truck J-20, the primary fitments are bias-ply tires, and that construction contributes to the truck's traditional heavy-duty visual character. Sidewall shape, tread presentation, and the overall stance of a bias-ply truck tire tend to look more in step with a late-1970s work pickup than a modernized substitute would.
That does not mean appearance is only about construction, because sidewall style and tire series matter too. A blackwall truck tire gives one kind of period-style presentation, while certain 750-16 options can create a more stylized restoration look. The best visual result still depends on using the correct size and wheel diameter first.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1978 Jeep Truck Truck J-20?
Yes. Modifications can change how a tire fits a 1978 Jeep Truck Truck J-20, especially if the truck has different wheels, altered suspension height, replacement axles, or body changes from years of work use. On this model, the presence of both 16-inch and 16.5-inch fitments already makes wheel verification especially important.
Even a correct tire size for one J-20 configuration should be checked against the truck's current setup. Pay close attention to actual wheel diameter, wheel width, steering clearance, and any signs that the truck no longer matches its original stance or wheel equipment before selecting a new bias-ply tire.
What should I inspect before driving a 1978 Jeep Truck Truck J-20 on new tires?
Before road use, inspect the wheels for correct diameter and condition, confirm the tires are mounted to suitable rims, and look over the truck's suspension and steering for looseness or wear. On an older J-20, it also makes sense to check brake condition, alignment behavior, and whether all four tires match the intended fitment.
After installation, monitor inflation, bead seating, and any rubbing during low-speed turning or suspension movement. A short local drive can reveal pull, vibration, or clearance issues before the truck is used more seriously. That kind of recheck is especially worthwhile on collector trucks that have spent long periods parked.
How should tires on a collector 1978 Jeep Truck Truck J-20 be maintained?
Collector-truck tires should be inspected regularly for cracking, flat spotting, cuts, bulges, unusual wear, and air loss, even when the 1978 Jeep Truck Truck J-20 is driven only occasionally. Bias-ply truck tires also benefit from routine pressure checks and from being kept clean and protected from prolonged heat and sunlight.
Storage conditions matter almost as much as mileage on a low-use pickup. Keep the truck away from moisture and ozone sources when possible, and look over the tires before every drive rather than assuming low annual mileage means they are ready for service. Age and inactivity can affect condition just as much as road use.
