1973 GMC Suburban Tires

A 1973 GMC Suburban can use several different tire sizes, including 700-15, G78-15, H78-15, L78-15, LR78-15, 700-16, 750-16, 875-16.5, and 950-16.5. The correct fitment depends on the exact C1500, C2500, K1500, or K2500 configuration, along with its GVWR and wheel diameter.

The safest starting point is the truck’s exact sub-model and the actual wheel now on the vehicle. Some Suburbans in this model year use 15-inch rims, some use 16-inch rims, and some use 16.5-inch rims, so choosing by year and body style alone is not enough. A quick check of the existing tire size and wheel diameter prevents crossing into the wrong fitment family.

The 1973 GMC Suburban uses more than one rim diameter across the model line. Depending on the specific truck, the applicable tire fitment may be built for a 15-inch, 16-inch, or 16.5-inch rim.

That difference matters because a tire made for one of those rim diameters cannot simply be treated as interchangeable with the others. Many of the Suburban’s tire-size questions are really wheel-diameter questions first, especially on heavier-duty C2500 and K2500 models. Before comparing sidewall style, construction, or radial alternatives, confirm the actual wheel size mounted on the truck now.

The 1973 GMC Suburban was offered in multiple 2-wheel-drive and 4-wheel-drive versions with different GVWR ratings, and those differences created several tire-fitment paths. Lighter-duty models stayed in the 15-inch group, while heavier-duty trucks could move into 16-inch or 16.5-inch sizes, with one 15-inch radial fitment also appearing on certain higher-GVWR versions.

That means the right tire is tied to the truck’s exact configuration rather than the Suburban name alone. A buyer looking at a C1500, for example, may be comparing a different fitment picture than someone working with a K2500. Wheel diameter, load-minded sizing, and existing setup should all be checked before settling on a replacement tire.

LR78-15 is a radial fitment for certain 1973 GMC Suburban applications. It uses the vintage alphanumeric radial format and appears on select higher-GVWR 15-inch Suburban configurations alongside bias-ply fitment patterns used elsewhere in the lineup.

That distinction is important because LR78-15 should not be treated as the default choice for every 15-inch Suburban. The truck must already match the correct wheel diameter and configuration for that size. Owners comparing it with bias-ply alternatives should also look at wheel width, overall tire dimensions, and the type of driving the Suburban is expected to handle.

G78-15 has radial equivalents in 205R15, P215/75R15, P225/70R15, and 710R15. H78-15 crosses to 215R15, P225/75R15, P235/70R15, and 760R15. L78-15 crosses to 235R15, P235/75R15, P255/70R15, and 820R15.

Those alternatives cover 80-series metric radial, 75-series P-metric radial, 70-series P-metric radial, and bias-look radial formats. They provide useful options for owners considering a change from a bias-ply presentation, but they still need to be checked against wheel width, wheel diameter, and clearance on the actual Suburban. Matching the original size category does not remove the need for a careful fitment review.

Start by confirming that the Suburban’s original bias-ply size has a radial equivalent in the same fitment family. On certain 15-inch sizes, that may include an 80-series metric radial, a 75-series or 70-series P-metric radial, or a bias-look radial alternative, depending on the original size.

The next checks are the actual wheel diameter, wheel width, and available clearance at the fenders and steering components. A Suburban that has been fitted with aftermarket wheels, altered suspension height, or a different load-carrying setup deserves extra attention before conversion. Construction changes can also affect the truck’s visual character, so many owners weigh road-use priorities against period-style appearance.

The first priority is matching the tire to the Suburban’s exact size and wheel diameter, since this model year spans 15-inch, 16-inch, and 16.5-inch fitments. After that, the important comparisons are construction type, sidewall style, tire series, and whether the truck needs a more passenger-style presentation or a more work-oriented truck tire.

A lighter-duty C1500 and a heavier K2500 may call for very different choices even if both are collector vehicles today. It also helps to think about how the truck will be used, whether that means show presentation, occasional cruising, or more utility-focused driving. Rim-width compatibility and load-minded product details deserve attention before making the final selection.

1973 GMC Suburban tire options include blackwall, wide whitewall, narrow whitewall, and dual-white-stripe sidewall treatments, depending on the size. Most of the heavier-duty truck sizes lean strongly toward blackwall options, while several 15-inch and 16-inch classic bias-ply sizes offer more decorative whitewall choices.

That gives the Suburban owner room to shape the truck’s overall look without stepping outside the correct size category. A blackwall usually supports a more utility-driven or truck-oriented presentation, while whitewall treatments move the appearance toward a more restoration-minded style. The right choice still has to begin with the correct fitment, since not every sidewall treatment appears in every size.

Tires for the 1973 GMC Suburban are available from Firestone, BFGoodrich, Coker Classic, STA, Lester, Avon, and Tornel, depending on the size. Brand availability changes across the fitment range, with some sizes offering multiple classic and truck-oriented choices while others are narrower in scope.

The most useful way to compare brands on this Suburban is by size-specific product character rather than by name alone. Some options emphasize whitewall styling and a more classic passenger look, while others focus on truck, military, highway, or traction-oriented designs. Once the correct size is confirmed, the brand decision becomes part of a larger appearance and use decision.

A period-style 1973 GMC Suburban tire choice starts with the truck’s exact original fitment family, whether that means a 15-inch, 16-inch, or 16.5-inch bias-ply size, or the LR78-15 radial fitment on certain configurations. From there, the appearance can lean toward classic whitewall presentation or a more truck-oriented blackwall look depending on the size.

Many restoration-minded owners want the tire to support the Suburban’s era without forcing a show-car look onto a utility vehicle. The key is staying within the correct size and wheel-diameter range first, then choosing the sidewall and tire series that match the truck’s intended character. When exact originality matters, marque-specific historical references are worth consulting before finalizing details.

Tire construction changes more than ride and road feel on a restored 1973 GMC Suburban; it also changes the truck’s visual character. A bias-ply tire generally preserves a more traditional truck-era presentation, while the LR78-15 radial or bias-look radial equivalents for certain 15-inch sizes can shift the look toward a later or slightly more modern appearance.

That visual difference is especially noticeable when the Suburban is being restored with a strong period theme. Sidewall treatment, tread style, and the overall stance created by the chosen size all work together, so construction should be part of the appearance decision instead of an afterthought. It helps to decide early whether the truck’s goal is road-minded practicality or a more traditional vintage presentation.

Yes, modifications can affect tire fitment on a 1973 GMC Suburban. Aftermarket wheels, wheel-width changes, suspension lifts or lowering, and steering or brake updates can all change the space available for the original tire size or any radial equivalent being considered.

That matters even more on a Suburban because the model year already spans several rim diameters and fitment families. A truck that no longer has its original wheel setup should be measured directly before replacement tires are chosen. Clearance at full steering lock, suspension travel, and wheel-to-fender relationship are all worth checking instead of assuming the original size category still applies unchanged.

Before driving a 1973 GMC Suburban on new tires, inspect the wheels for the correct diameter and condition, confirm that the tires are seated properly, and verify inflation pressure. It also makes sense to look over the steering, suspension, and brake components, since worn hardware can affect how a large truck responds even with fresh tires installed.

A short, careful road test is a smart next step, especially if the Suburban has been stored or recently restored. Listen for rubbing, watch for pull or vibration, and recheck pressure after the initial drive. Collector trucks often sit for long periods, so roadworthiness depends on the whole setup around the tire, not just the tire itself.

Tires on a collector 1973 GMC Suburban should be checked regularly for air loss, cracking, cuts, bulges, and uneven tread wear, even if the truck sees limited mileage. Proper inflation and clean, dry storage away from prolonged sun and ozone sources help preserve both appearance and serviceability.

Large vintage utility vehicles often spend more time parked than driven, which can hide condition issues until the truck is asked to cover real road miles. Periodic inspection is especially important before seasonal drives or longer trips. It is also wise to review the spare, since an old Suburban can carry a tire that looks acceptable at a glance but is no longer trustworthy in use.