The 1971 American Motors Gremlin arrived at the start of the compact-car boom, giving AMC a short-wheelbase hatchback with a character all its own. That unusual shape and economy-minded mission make the Gremlin a memorable survivor today, but tire selection is more involved than it first appears. The 1971 American Motors Gremlin uses several primary bias-ply tire sizes depending on sub-model, including 600-13, 6.45-14, 6.45-15, B78-14, and D70-14. Available choices range from whitewall-oriented bias-ply options to Firestone Wide Oval styles, and select sizes also have modern radial equivalents. The key is matching the exact sub-model and wheel diameter before deciding between restoration-style appearance and an alternative road-use approach.
Which Tire Size Is Right for The 1971 American Motors Gremlin
The 1971 American Motors Gremlin uses five primary tire sizes, and the correct one depends on the exact sub-model and wheel setup. These fitments are all bias-ply, but they span 13-inch, 14-inch, and 15-inch rim diameters, so confirming the Gremlin's specific sub-model and actual wheel diameter is the first step before comparing tire style, appearance, or radial-equivalent options.
A 6.45-14 size is a numeric bias-ply designation in which 6.45 refers to the tire's nominal section width in inches and 14 identifies the wheel diameter. Its bias-ply construction suits a traditional compact-car fitment and preserves the vintage sizing convention used on certain 1971 Gremlin configurations. This size is best approached as a period-style replacement choice rather than a broad substitute for every Gremlin. Before selecting it, confirm that the car actually uses the 14-inch wheel setup associated with this fitment.
A 600-13 tire is a numeric bias-ply size, with 6.00 indicating nominal section width and 13 indicating rim diameter. On the 1971 American Motors Gremlin, it represents one of the smaller primary fitments and keeps the car in a distinctly vintage tire format. Available options in this size include BFGoodrich Silvertown Classic Bias Ply tires with both wide whitewall and narrow whitewall treatments. It is a useful choice for an owner focused on traditional appearance, especially after confirming the Gremlin is equipped with the correct 13-inch wheels.
The 6.45-15 code follows the same numeric bias-ply pattern, with a nominal 6.45-inch section width and a 15-inch rim diameter. Its role on the 1971 Gremlin is tied to specific sub-model fitment rather than a general all-model application, so wheel diameter matters immediately. This size keeps the car in a fully vintage bias-ply construction and should be evaluated with that traditional tire character in mind. It makes sense for owners who are preserving the original style of a 15-inch wheel setup and want to avoid mixing fitment conventions.
B78-14 is a vintage alphanumeric bias-ply size in which the letter indicates the tire's size class, the 78 identifies its profile family, and the 14 is the rim diameter. For a 1971 American Motors Gremlin, this format reflects a later-era bias-ply convention than the older numeric sizes while still remaining fully period in character. It can also be cross-shopped with several radial-equivalent formats for owners considering a construction change. The important step is confirming that the Gremlin's exact sub-model and wheel setup call for this 14-inch alphanumeric fitment.
A D70-14 tire uses the vintage alphanumeric bias-ply system, where the letter marks the overall size class, 70 indicates the profile family, and 14 is the wheel diameter. On the 1971 Gremlin, this size is tied to the X sub-model and carries a more performance-flavored visual presence than the smaller numeric sizes. Firestone Wide Oval choices in this fitment include raised white letter, redline, and pin white stripe sidewall treatments. It is the size to examine closely when appearance is a major priority and the car is confirmed to have the proper 14-inch setup.
Sub-model fitment matters on the 1971 American Motors Gremlin because tire size varies across the covered versions. Before choosing a tire, identify whether the car is a 6 Cyl. Non-Air model, a 6 Cyl. w/Air model, or a Gremlin X, then confirm the wheel diameter actually on the car.
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1971 American Motors Gremlin 6 Cyl. Non-Air
The 1971 American Motors Gremlin 6 Cyl. Non-Air uses either a 6.45-14 or 600-13 bias-ply fitment, which means wheel diameter must be verified before tire selection starts. That makes this sub-model a wheel-confirmation decision first, followed by a choice between a traditional bias-ply presentation and, for 600-13, available radial-equivalent sizing paths.
The 1971 American Motors Gremlin 6 Cyl. w/Air uses either 6.45-15 or B78-14, so this version also requires careful confirmation of the actual rim diameter on the car. Once that is settled, the decision becomes whether to stay with the original-style bias-ply construction or, in the case of B78-14, consider one of the radial-equivalent alternatives.
The 1971 American Motors Gremlin X uses the D70-14 bias-ply size, giving this sub-model a more focused tire-selection path than the other covered Gremlin versions. The main choice here is less about fitment variation and more about selecting the sidewall style that best suits the car's intended appearance and use.
Bias-Ply to Radial Tire Conversion for the 1971 American Motors Gremlin
Two primary Gremlin sizes have radial-equivalent options: 600-13 and B78-14. For 600-13, the available alternatives are 165R13 as an 80-series metric radial, P165/75R13 as a 75-series P-metric radial, and P175/70R13 as a 70-series P-metric radial. For B78-14, the equivalents are 155R14, P175/75R14, and P185/70R14 in the same respective categories. Recommended rim-width ranges are 4-5 inches for 600-13 and 4-6 inches for B78-14, and each option should still be checked against wheel dimensions and vehicle clearance.
Modern Radial Equivalents
165R13
Equivalent 80-series Metric Radial (600-13)
P165/75R13
Equivalent P-metric 75-series Radial (600-13)
P175/70R13
Equivalent P-metric 70-series Radial (600-13)
155R14
Equivalent 80-series Metric Radial (B78-14)
P175/75R14
Equivalent P-metric 75-series Radial (B78-14)
P185/70R14
Equivalent P-metric 70-series Radial (B78-14)
Important Considerations When Replacing Bias Ply With Radial
Compare overall diameter and section width carefully to ensure proper fit.
Verify recommended rim range (4-6 in) and load needs match your vehicle specifications.
Check fender clearance, steering clearance, and stance before installation.
Consider suspension condition and intended road use when choosing equivalents.
Important Fitment Notes
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 1971 American Motors Gremlin Tires for Sale
Available Gremlin tire choices focus on 600-13 and D70-14, with BFGoodrich Silvertown Classic Bias Ply whitewall options in 600-13 and Firestone Wide Oval styles in D70-14. Sidewall treatments include wide whitewall, narrow whitewall, raised white letter, redline, and pin white stripe.
The questions below focus on the tire sizes used on the 1971 American Motors Gremlin, how fitment changes by sub-model, and how to sort through bias-ply, radial-equivalent, sidewall, and road-use decisions before mounting a new set.
Tire Size & Fitment
What tire size fits a 1971 American Motors Gremlin?
A 1971 American Motors Gremlin can use 6.45-14, 600-13, 6.45-15, B78-14, or D70-14, depending on the exact sub-model and wheel setup. All of these are primary bias-ply fitments, but they do not apply universally across every Gremlin configuration.
The practical decision starts with identifying the specific sub-model and confirming the wheel diameter on the car. A Gremlin with 13-inch wheels needs a different tire path than one using 14-inch or 15-inch rims, and that matters before comparing sidewall style, tire series, or possible radial-equivalent alternatives.
What size rim does a 1971 American Motors Gremlin use?
The 1971 American Motors Gremlin appears with 13-inch, 14-inch, and 15-inch rim diameters depending on the tire size and sub-model. That range includes 600-13 on a 13-inch rim, 6.45-14, B78-14, and D70-14 on 14-inch rims, and 6.45-15 on a 15-inch rim.
Wheel diameter should be confirmed before ordering tires because several Gremlin fitments are close in naming style but not interchangeable by rim size. Checking the stamping on the wheel, measuring the wheel correctly, and verifying the car's current setup is especially important if the vehicle has changed hands or has been modified over time.
Why does the 1971 American Motors Gremlin have more than one tire size?
The 1971 American Motors Gremlin has more than one tire size because fitment varies by sub-model. The 6 Cyl. Non-Air, 6 Cyl. w/Air, and Gremlin X do not all use the same primary tire sizing, and the sizes also span different rim diameters.
That means the right tire cannot be chosen by year, make, and model alone. A buyer should confirm the exact Gremlin version first, then verify whether the car still carries its intended wheel diameter before moving on to appearance choices such as whitewall, raised white letter, redline, or pin white stripe.
Bias-Ply & Radial Options
Is 600-13 a bias-ply or radial tire for the 1971 American Motors Gremlin?
For the 1971 American Motors Gremlin, 600-13 is a primary bias-ply tire size. It uses the older numeric sizing format, where the first number indicates nominal section width and the final number identifies the 13-inch rim diameter.
That matters because a buyer may see radial equivalents for 600-13 and assume the original fitment was radial, which it was not. Keeping the car in bias-ply preserves the vintage construction and look, while moving to a radial alternative calls for checking rim width, wheel condition, and clearance before making the change.
What radial tire sizes are equivalent to 600-13 and B78-14?
For 600-13, radial equivalents include 165R13, P165/75R13, and P175/70R13. For B78-14, the equivalent radial sizes are 155R14, P175/75R14, and P185/70R14. These cover an 80-series metric radial format, a 75-series P-metric radial format, and a 70-series P-metric radial format for each primary size.
Those alternatives give a 1971 Gremlin owner more than one way to move from a vintage bias-ply size into a modern radial sizing convention. Rim-width guidance is also part of the decision, with 4-5 inches associated with 600-13 equivalents and 4-6 inches associated with B78-14 equivalents, alongside normal wheel and clearance checks.
What should I check before converting my 1971 American Motors Gremlin from bias-ply to radial tires?
A 1971 American Motors Gremlin owner considering a bias-ply-to-radial conversion should start by matching the radial equivalent to the correct original primary size. That means identifying whether the car uses 600-13 or B78-14 before looking at 165R13, P165/75R13, P175/70R13, 155R14, P175/75R14, or P185/70R14.
The next step is confirming that the wheel diameter and rim width suit the radial option under consideration, then checking steering and fender clearance on the actual car. It also helps to inspect suspension condition and wheel integrity, since a collector vehicle may have aged components even if the tread mileage is low.
Choosing the Right Tire
What should I consider when choosing a 1971 American Motors Gremlin tire?
Start with the exact primary tire size required for the Gremlin's sub-model and wheel diameter, because this car spans five different bias-ply fitments. After size is confirmed, the next priorities are construction, intended appearance, and whether the goal is a restoration-style presentation or a radial-equivalent path where one exists.
Product differences matter most when they affect the look or wheel match of the car. A 600-13 Gremlin can be steered toward whitewall styling, while a D70-14 Gremlin X can be matched with Firestone Wide Oval visual treatments, so the best choice depends on the vehicle's setup and how it is meant to be used.
What sidewall styles are available for 1971 American Motors Gremlin tires?
Available sidewall styles for 1971 American Motors Gremlin tires include wide whitewall and narrow whitewall in 600-13, plus raised white letter, redline, and pin white stripe in D70-14. Those choices create very different visual results even when the tire remains within the correct primary fitment family.
Sidewall style should be chosen after the correct size is established, not before. A whitewall treatment suits a more traditional compact-car look, while the Firestone Wide Oval sidewalls in D70-14 give the Gremlin X a stronger performance-era appearance, so the visual goal can be just as important as the tire's construction.
What brands offer tires for the 1971 American Motors Gremlin?
BFGoodrich and Firestone both offer tires for the 1971 American Motors Gremlin in applicable primary sizes. BFGoodrich appears in 600-13 through the Silvertown Classic Bias Ply line, while Firestone appears in D70-14 through the Wide Oval series.
Brand choice should be considered within the correct size rather than as a starting point by itself. Once the Gremlin's sub-model and wheel diameter are confirmed, the useful comparison becomes sidewall treatment, tire series character, rim-width specification, and whether the overall look matches the way the car is being restored or driven.
Restoration & Appearance
Which tire should I choose for a period-style 1971 American Motors Gremlin?
A period-style 1971 American Motors Gremlin should begin with the correct primary bias-ply size for its exact sub-model and wheel diameter. That keeps the tire's sizing convention and construction in line with the car's early-1970s character before any appearance details are considered.
From there, the visual direction depends on the specific Gremlin. A 600-13 car can lean toward whitewall styling, while a D70-14 Gremlin X opens the door to Firestone Wide Oval treatments. When exact originality matters, compare the chosen size and sidewall treatment against marque references or surviving vehicle documentation.
How does tire construction affect the appearance of a restored 1971 American Motors Gremlin?
Tire construction has a visible effect on a restored 1971 American Motors Gremlin because the primary fitments are bias-ply, and that construction carries the vintage sizing language and overall presentation associated with the period. A radial equivalent can change the look simply by moving into a different sizing convention.
That does not mean a radial alternative is automatically wrong for the car; it means the owner should be clear about priorities. A restoration-oriented Gremlin often benefits visually from staying with the original bias-ply format, while a driver-focused car may justify an equivalent radial after wheel, clearance, and profile considerations are checked.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1971 American Motors Gremlin?
Yes, modifications can affect tire fitment on a 1971 American Motors Gremlin even when the tire size itself is correct for the original sub-model. Changes such as aftermarket wheels, altered wheel width, suspension work, or body adjustments can all influence whether a given tire has the proper clearance and stance.
That is especially important on a Gremlin because the model already spans 13-inch, 14-inch, and 15-inch fitments. A car that no longer carries its original wheels should be measured carefully before ordering, and any radial-equivalent conversion deserves the same close look at wheel dimensions and steering clearance.
What should I inspect before driving a 1971 American Motors Gremlin on new tires?
Before driving a 1971 American Motors Gremlin on new tires, inspect the wheels for correct diameter and condition, then confirm the tires are mounted in the proper size for the car's sub-model. It also helps to check inflation pressure, valve stems, lug hardware, and visible clearance around the suspension, fenders, and steering components.
A collector Gremlin may spend long periods parked, so the rest of the chassis deserves attention too. Look for worn steering parts, weak shocks, uneven ride height, or brake issues that could affect how the car tracks on fresh tires, especially when moving from older worn rubber to a newly installed set.
How should tires on a collector 1971 American Motors Gremlin be maintained?
Tires on a collector 1971 American Motors Gremlin should be maintained through regular pressure checks, routine visual inspections, and careful storage habits during long periods of non-use. Even a car that covers very few miles can develop sidewall cracking, flat spotting, air loss, or age-related deterioration that is easy to miss in the garage.
Keeping the car away from prolonged heat, sunlight, and ozone sources helps preserve the rubber, and moving or driving the Gremlin periodically can reduce set-in flat spots. It is also wise to inspect tread wear patterns from time to time, since unusual wear can point to alignment, suspension, or wheel issues rather than tire problems alone.
