The 1991 Isuzu Trucks Trooper came from an era when compact and midsize sport utilities were still built with real truck character, and the Trooper earned its following with upright styling, off-road credibility, and honest utility. For this exact model year, tire selection centers on two 15-inch radial sizes: 235/75R15 and the larger 31X10.50R15 flotation-style light truck fitment. That gives owners a choice between a more conventional metric radial and a taller, wider all-terrain presentation, with available options ranging from raised white letter truck tires to several whitewall radial styles. The right choice depends on the wheel setup already on the vehicle and whether the goal is utility, stance, or a more restoration-minded look.
Which Tire Size Is Right for The 1991 Isuzu Trucks Trooper
The 1991 Isuzu Trucks Trooper uses two primary tire sizes, and both are radial tires built for 15-inch wheels. Because every covered sub-model can use either 235/75R15 or 31X10.50R15, the first step is confirming which wheel and tire setup is already on the vehicle. Once that is established, the decision shifts to tire style, overall look, and whether a more road-focused or all-terrain presentation makes the most sense.
The 235/75R15 size uses modern metric sizing: 235 is the nominal section width in millimeters, 75 is the aspect ratio, R designates radial construction, and 15 is the wheel diameter in inches. On the 1991 Isuzu Trucks Trooper, this size delivers a conventional radial fitment on a 15-inch rim and suits owners who want a familiar metric replacement size. Product choices in this size vary widely, including BFGoodrich, American Classic, Maxxis, Coker Classic, Tornel, and Travelstar options with raised white letter, narrow whitewall, and wide whitewall treatments. It is the size to evaluate when the Trooper already carries a metric-style 15-inch tire and the buyer wants the broadest range of appearance options.
The 31X10.50R15 size is a flotation-style radial format that states the approximate overall tire diameter first, then the nominal section width in inches, followed by the 15-inch rim diameter. On the 1991 Isuzu Trucks Trooper, it represents a taller and wider 15-inch radial fitment than 235/75R15, giving the vehicle a more truck-oriented stance. The available product choice in this size centers on the BFGoodrich All-Terrain T/A KO2 with raised white letter sidewalls and an all-terrain tire character. It is the size to check when the Trooper already wears a 31-inch setup and wheel width, clearance, and intended use support that larger footprint.
Fitment across the 1991 Isuzu Trucks Trooper sub-model range is straightforward because LS, S, SE, and XS can all use the same two radial tire sizes. Checking the exact sub-model still helps confirm that the wheel and tire setup currently on the vehicle matches the size you plan to replace.
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1991 Isuzu Trucks Trooper LS
The 1991 Isuzu Trucks Trooper LS can use the same two 15-inch radial sizes found across the broader Trooper range, so size choice comes down more to the vehicle's current wheel-and-tire setup than trim level alone. That makes it important to confirm whether the LS is on 235/75R15 metric radials or a 31X10.50R15 flotation-style setup before comparing tread style and sidewall appearance.
The 1991 Isuzu Trucks Trooper S shares the same radial tire-size range as the other covered sub-models, with both primary options built for 15-inch wheels. Tire selection is therefore less about the S designation itself and more about verifying which size is already fitted, then choosing the look and road-use character that best matches the vehicle.
The 1991 Isuzu Trucks Trooper SE uses the same two 15-inch radial fitments as the rest of the covered lineup, so the key step is confirming which size is on the vehicle now. From there, the decision becomes whether to stay with a conventional 235/75R15 metric radial or continue with the taller 31X10.50R15 truck-style presentation.
The 1991 Isuzu Trucks Trooper XS follows the same basic tire-fitment pattern as LS, S, and SE, with both primary radial sizes built around a 15-inch wheel. That means the XS owner should verify the actual wheel and tire combination on the truck first, then compare available sidewall style and tread character within that confirmed size.
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 1991 Isuzu Trucks Trooper Tires for Sale
Available 1991 Isuzu Trucks Trooper tire choices span BFGoodrich, American Classic, Maxxis, Coker Classic, Tornel, and Travelstar products. Across the two primary sizes, buyers can compare all-terrain versus classic radial character, plus raised white letter, narrow whitewall, and wide whitewall sidewall styles.
These answers focus on the tire sizes used on the 1991 Isuzu Trucks Trooper, how the two 15-inch radial fitments differ, and what to check when comparing appearance, wheel compatibility, and road-use readiness.
Tire Size & Fitment
What tire size fits a 1991 Isuzu Trucks Trooper?
The 1991 Isuzu Trucks Trooper uses two primary tire sizes: 235/75R15 and 31X10.50R15. Both are radial tires built for 15-inch wheels, and both sizes appear across the covered Trooper sub-models rather than being limited to one trim alone.
That means the real fitment question is not just model year and trim, but which wheel-and-tire setup is already on the vehicle. A Trooper wearing 235/75R15 should usually be replaced within that same size unless a deliberate change is being evaluated, while a Trooper already on 31X10.50R15 should have wheel width and clearance confirmed before staying with the larger flotation-style size.
What size rim does a 1991 Isuzu Trucks Trooper use?
Both primary tire sizes used on the 1991 Isuzu Trucks Trooper are designed around a 15-inch rim diameter. That applies to the 235/75R15 metric radial and the 31X10.50R15 flotation-style radial, so wheel diameter remains consistent even though the overall tire dimensions differ.
Rim diameter is only one part of the fitment picture, so it is still worth checking actual wheel width before selecting a replacement tire. The available 235/75R15 products span several rim-width specifications, and the 31X10.50R15 all-terrain option calls for a wider rim range, making the existing wheel an important part of the decision.
Do all 1991 Isuzu Trucks Trooper sub-models use the same tire size?
LS, S, SE, and XS versions of the 1991 Isuzu Trucks Trooper can all use the same two tire sizes: 235/75R15 and 31X10.50R15. In other words, the covered sub-models share the same size range instead of each trim carrying its own unique tire fitment.
That shared fitment range still does not mean every individual Trooper is wearing the same wheel-and-tire combination today. After years of use, many sport utilities receive replacement wheels or a different tire size, so the safest approach is to verify the size mounted on the vehicle and compare it against the wheel dimensions before ordering a replacement.
Choosing the Right Tire
What should I consider when choosing a 235/75R15 or 31X10.50R15 tire for a 1991 Isuzu Trucks Trooper?
Start with the size that is already on the vehicle, because the 1991 Isuzu Trucks Trooper uses either 235/75R15 or 31X10.50R15 on a 15-inch rim. From there, compare the tire's character and appearance, since the smaller metric size has a wide range of classic whitewall and truck-style options while the 31-inch size is centered on an all-terrain raised white letter presentation.
Wheel width matters just as much as the size code on the sidewall. A 235/75R15 can suit several different visual directions, while the 31X10.50R15 asks for a wider wheel range and more physical space around the tire, so the existing rim, vehicle stance, and intended driving use should guide the final choice.
What sidewall styles are available for 1991 Isuzu Trucks Trooper tires?
Sidewall choices for the 1991 Isuzu Trucks Trooper include raised white letter, narrow whitewall, and wide whitewall depending on the tire size and series selected. The broadest variety appears in 235/75R15, while 31X10.50R15 is represented by a raised white letter all-terrain tire.
That variety lets the same Trooper move in very different visual directions. Raised white letter sidewalls lean toward a truck and utility look, while narrow or wide whitewalls create a more customized or restoration-oriented appearance, so the best choice depends on whether the vehicle is being kept rugged, personalized, or more visually tied to an earlier classic-tire style.
What brands offer tires for the 1991 Isuzu Trucks Trooper?
Tires for the 1991 Isuzu Trucks Trooper are available from BFGoodrich, American Classic, Maxxis, Coker Classic, Tornel, and Travelstar. Most of that variety is found in 235/75R15, while the available 31X10.50R15 choice is a BFGoodrich All-Terrain T/A KO2.
Brand alone should not be the only filter when narrowing the selection. It helps to compare size, sidewall treatment, tire series, rim-width compatibility, and load specification at the same time, especially since some choices are clearly aimed at classic appearance while others are more focused on utility and truck-style road use.
Restoration & Appearance
Which tire should I choose for a period-style 1991 Isuzu Trucks Trooper?
A period-style 1991 Isuzu Trucks Trooper tire choice usually begins by keeping the vehicle in one of its two primary 15-inch radial sizes, either 235/75R15 or 31X10.50R15. From there, the appearance direction becomes the deciding factor, since 235/75R15 opens the door to several whitewall radial options while 31X10.50R15 presents a more truck-oriented all-terrain look.
Owners pursuing a stock-looking sport utility should pay close attention to the tire already on the vehicle, the wheel width, and the visual tone they want to preserve. Exact originality questions are best checked against period brochures, marque references, or surviving examples, because a tire can suit the era well without being presented as a proven factory-original specification.
How does tire construction affect the appearance of a restored 1991 Isuzu Trucks Trooper?
On the 1991 Isuzu Trucks Trooper, construction is simpler than on many older collector vehicles because both primary fitments are radial tires. The visual differences come less from bias-ply versus radial choice and more from the tire size, sidewall treatment, and whether the vehicle wears a conventional metric radial or a taller flotation-style light truck tire.
That means appearance is shaped by proportion and sidewall style rather than a construction change. A 235/75R15 with a narrow or wide whitewall gives the Trooper a more styled presentation, while a 31X10.50R15 raised white letter all-terrain emphasizes its utility roots, so the best match depends on the kind of restoration or vintage presentation being pursued.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 1991 Isuzu Trucks Trooper?
Yes, modifications can change how either 235/75R15 or 31X10.50R15 fits a 1991 Isuzu Trucks Trooper. Aftermarket wheels, changes in wheel width, altered offset, suspension lifts, lowering, or body modifications can all affect clearance even when the tire size itself is one of the sizes commonly used on this vehicle.
A Trooper that has been changed from its original wheel-and-suspension setup should be checked at steering lock and through suspension travel before replacing tires. That becomes especially important with 31X10.50R15, since the tire is taller and wider than 235/75R15 and asks more of the available space around the wheel opening and chassis.
What should I inspect before driving a 1991 Isuzu Trucks Trooper on new tires?
Before putting a 1991 Isuzu Trucks Trooper into regular road use on new tires, inspect the wheel condition, confirm correct tire pressure, and make sure the tires clear the suspension, steering components, and fenders. It is also wise to look over the vehicle's brakes, shocks, steering linkage, and alignment if the Trooper has been sitting or has seen uneven tire wear.
A fresh set of tires will only perform as intended if the rest of the vehicle is ready for them. Pay attention to any rubbing, pull, vibration, or unusual wear pattern during the first miles, since those early signs can point to wheel-width issues, alignment problems, or a clearance concern that should be corrected before longer trips.
How should tires on a collector 1991 Isuzu Trucks Trooper be maintained?
Collector-use tires on a 1991 Isuzu Trucks Trooper should be inspected regularly for cracking, cuts, bulges, uneven wear, and gradual air loss, even if the vehicle is driven only occasionally. Radial tires on low-use sport utilities can age out before they wear out, so condition matters just as much as remaining tread depth.
Storage habits also affect longevity. Keeping the Trooper away from prolonged sunlight, excess heat, moisture, and ozone-producing equipment helps protect the rubber, and moving the vehicle periodically can reduce flat-spotting from long periods of inactivity. A pressure check before each outing is a good habit, especially on a truck that may sit for weeks between drives.
