Plymouth GTX Tires

The Plymouth GTX uses two tire sizes in this listing: G70-14 and G78-14, both for the 1971 model year. Both are alphanumeric bias-ply sizes built for 14-inch rims. G70-14 products list recommended rim widths from 6.0 to 8.0 inches or 6.50 to 7.00 inches depending on brand, while G78-14 products list 5.00 to 7.00 inch rim widths.

That means the correct choice is not just about the year, but also about the actual wheel on the car and the look you are trying to preserve. If your Plymouth GTX has been restored, modified, or fitted with replacement wheels over the years, measure the rim width and compare the existing tire size before choosing between G70-14 and G78-14.

G70-14 is an alphanumeric bias-ply tire size used on the 1971 Plymouth GTX. The letter G identifies the tire’s width class, the 70 is the series designation used in this period sizing system, and the 14 indicates a 14-inch rim diameter. The available Plymouth GTX products in this size are all bias-ply construction.

For a buyer, that code matters because it ties together both the wheel size and the tire’s period-correct proportions. If your Plymouth GTX already wears G70-14 tires, that is the first clue you are looking at the right fitment family, but you should still confirm wheel width so the tire matches the rim properly and keeps the intended stance.

A 1971 Plymouth GTX can show both G70-14 and G78-14 because two distinct alphanumeric bias-ply sizes are associated with that model year. The split is not a wheel-diameter change, since both sizes use 14-inch rims, and it is not a construction split, since both are bias-ply. The difference is primarily a same-year fitment variation tied to configuration and wheel-width suitability.

That is why the year alone does not fully settle the choice. The practical way to sort it out is to inspect the wheels currently on the Plymouth GTX, note the installed size if the car has an older period-style tire, and compare the overall restoration goal, especially if you are deciding between muscle-car redline or RWL looks and a more traditional whitewall presentation.

The Plymouth GTX tires listed here are all alphanumeric bias-ply designs, and a tube is required for these fitments. Both G70-14 and G78-14 products are bias-ply construction on 14-inch rims. No radial options appear in this Plymouth GTX range.

That matters during installation because tube fitment is part of a correct vintage tire setup, not an afterthought. If a Plymouth GTX has been sitting for a long period or is being freshly restored, inspect the wheels carefully for rust, damage, or old hardware that could affect the tube and tire assembly before the car goes back into road or show service.

Start with the size already on the car, then verify the wheel diameter and wheel width. A 1971 Plymouth GTX in this range takes either G70-14 or G78-14, and both require a 14-inch rim. The listed rim-width ranges differ between those sizes, so the wheel itself is an important part of the decision.

If the Plymouth GTX has a known restoration history, compare the current setup with any build records, old photos, or marque references tied to that exact car. That extra step helps separate a later tire substitution from an intentional period-style choice and is especially useful when selecting between a more aggressive muscle-car presentation and a more traditional whitewall look.

Plymouth GTX tires in this range are available with several sidewall styles, including redline, RWL, blackwall, pin white stripe, narrow whitewall, dual white stripe, and wide whitewall. G70-14 offerings lean toward period muscle-car treatments such as redline, RWL, blackwall, and pin white stripe. G78-14 offerings lean more toward narrow, dual, and wide whitewall styles.

That variety lets a Plymouth GTX owner match the tire to the car’s intended character. If the goal is a factory-style muscle car appearance, the G70-14 sidewall choices are the more performance-oriented visual fit, while G78-14 whitewall options may suit a more personalized presentation or a car whose current setup already points in that direction.

Three brands appear in the Plymouth GTX range: Firestone, Goodyear, and BFGoodrich, along with Coker Classic-branded bias-ply offerings. Firestone and Goodyear appear in G70-14, while BFGoodrich and Coker Classic appear in G78-14. The listed tire series include Firestone Wide Oval, Goodyear Custom Wide Tread, Silvertown Classic Bias Ply, and Coker Classic Bias Ply.

Brand choice usually comes down to the exact size you need and the sidewall style that best matches the car. A Plymouth GTX restoration focused on muscle-era appearance may naturally center on the G70-14 offerings, while a car using G78-14 has different branding and sidewall choices available, so confirm size first and let brand selection follow from that.

The Plymouth GTX range includes Firestone Wide Oval, Goodyear Custom Wide Tread, Silvertown Classic Bias Ply, and Coker Classic Bias Ply series. All are bias-ply constructions, but they differ in brand identity, sidewall presentation, and the size in which they are offered. Firestone Wide Oval and Goodyear Custom Wide Tread are offered in G70-14, while Silvertown Classic Bias Ply and Coker Classic Bias Ply are offered in G78-14.

For a buyer, the main implication is visual and fitment-driven rather than a bias-versus-radial decision. Choose the Plymouth GTX tire series that matches the correct size first, then narrow the field by sidewall style, whether that means redline, raised white letter, blackwall, pin stripe, or one of the whitewall treatments associated with the G78-14 options.

A Plymouth GTX stored on fitted tires should be kept in a cool, dry, dark space away from direct sunlight, ozone sources, and large temperature swings. Clean tires and wheels before storage, maintain proper inflation, and move the car occasionally if it will sit for long periods. Bias-ply tires especially benefit from conditions that reduce flat-spotting and sidewall stress.

Collectors often support a Plymouth GTX with the tires carrying only normal load rather than leaving the car compressed under extra weight from stored parts or a packed trunk. If the car will be parked for a season, inspect the tread and sidewalls before and after storage so any cracking, distortion, or pressure loss is caught early rather than after the car is back in use.

Tires on a Plymouth GTX should be inspected at the start of the driving season, before any longer trip, and any time the car has been sitting for an extended period. Look for cracks, bulges, irregular wear, cuts, pressure loss, and signs of age around the bead and sidewall. Because the listed Plymouth GTX tires are bias-ply designs, regular visual inspection is especially important on a collector car that may not see frequent mileage.

A practical routine is to make tire inspection part of every pre-drive walkaround. Check inflation against the tire’s requirements, watch for changes in steering feel or vibration once underway, and inspect the tubes and wheel condition whenever the tires are dismounted, since a vintage-style setup depends on the whole assembly rather than the casing alone.

Plymouth GTX tires should be replaced when age, cracking, hardening, impact damage, or structural concerns appear, even if the tread still looks deep. Collector cars often age out tires long before they wear them out. On a bias-ply Plymouth GTX, visible sidewall deterioration or a noticeable change in ride quality is a strong signal that replacement deserves immediate attention.

Tread depth alone is not a reliable measure on a low-mileage hobby car. If a Plymouth GTX has older tires of uncertain age, or if the car has spent years parked, have the tires and tubes evaluated during service so you are not relying on appearance alone when deciding whether the set is still suitable for continued road use.

The Plymouth GTX range here includes two period-style sizes, G70-14 and G78-14, with several bias-ply series and sidewall treatments. Firestone Wide Oval and Goodyear Custom Wide Tread appear in G70-14, while Silvertown Classic Bias Ply and Coker Classic Bias Ply appear in G78-14. That means more than one authentic-looking approach exists within the 1971 Plymouth GTX size range.

To pin down what belongs on one specific Plymouth GTX, compare the car’s known history, original paperwork, and marque-club references rather than relying on year alone. That is the best way to determine whether the car should wear a muscle-era redline or RWL style, or whether its present wheel and trim combination point toward the alternate G78-14 bias-ply fitment.

Correct tire fitment can absolutely affect both presentation and judging for a Plymouth GTX. Size, sidewall style, and overall period appearance all shape how authentic the car looks, especially on a prominent muscle car where tires contribute heavily to stance. A Plymouth GTX wearing the right 14-inch bias-ply size and an era-appropriate sidewall usually reads more convincingly than a car with a visually inconsistent setup.

For owners concerned with show standards, the best reference point is the judging philosophy used by the relevant Mopar or marque community. Even outside formal judging, selecting a Plymouth GTX tire that matches the car’s wheel width, era, and intended presentation helps preserve the visual balance collectors expect from a properly sorted muscle car restoration.

Several sidewall styles are available for Plymouth GTX tires, including redline, RWL, blackwall, pin white stripe, narrow whitewall, dual white stripe, and wide whitewall. Within this range, G70-14 carries the more aggressive muscle-era visual treatments, while G78-14 carries the whitewall-focused options. All are bias-ply styles suited to a period presentation, but they do not create the same overall character.

The right sidewall for a Plymouth GTX restoration depends on the exact way the car is being restored and the visual standard you are trying to match. A concours-oriented car should follow marque references tied to its original configuration, while a driver-quality restoration can still look historically coherent if the sidewall style matches the car’s wheel, trim, and muscle-era personality.

These Plymouth GTX tires are period-style bias-ply designs intended for 14-inch wheels, and they can be suitable for public-road use when they are correctly sized, properly installed, and in sound condition. Safety depends on the entire setup: tire age, inflation, wheel condition, tube condition, and the mechanical state of the car. A visually attractive collector tire is not automatically a ready-to-drive tire if the rest of the assembly has been neglected.

A prudent Plymouth GTX owner should treat tire selection as one part of overall roadworthiness. Before regular driving, inspect the wheels, confirm the size matches the car, and be realistic about how a bias-ply muscle car behaves compared with a modern radial-equipped vehicle, especially under braking, in rain, or on grooved pavement.

Before driving a Plymouth GTX, check tire inflation, visible sidewall condition, tread condition, valve stems, and any sign that a tube-equipped assembly has been losing air. Confirm that all four tires are the intended size and that the wheels match the 14-inch fitment required by G70-14 or G78-14. On a car that has been parked, also look for flat spotting or age-related cracking before it returns to road use.

The broader safety check should include brakes, steering, suspension, and alignment, because tire performance depends on those systems being right as well. A Plymouth GTX with correct tires but poor front-end condition can still feel unstable, so a short local shakedown drive after service is a sensible way to confirm the whole package is working together.

A Plymouth GTX on period-style bias-ply tires should be driven with the understanding that these tires deliver a vintage driving feel rather than modern high-speed radial behavior. Even when the size is correct and the tires are in good condition, steering response, tracking, and braking feel will differ from modern expectations. Appropriate speed is the speed that stays within the tire’s condition, the road surface, and the overall preparedness of the car.

For most collectors, that means driving a Plymouth GTX with a margin of restraint rather than exploring the car’s full performance potential on old-school tire construction. Smooth inputs, extra following distance, and caution in heat, rain, or rough pavement are part of using a bias-ply-equipped muscle car responsibly and in a way that respects both the tire design and the car itself.