The 2012 Infiniti M56 sits in the final era of Infiniti’s rear-drive performance luxury sedans, blending V8 power with a more modern executive-car footprint than earlier Japanese sport sedans. For many owners, it is a car that balances comfort, presence, and serious highway pace. Tire fitment depends on the exact version, with 245/50R18 radial tires used on the Luxury and X models and 245/40R20 radials used on the Sport. That split also changes the look of the car, since available choices range from blackwall performance radials to RWL and redline presentations. The right selection starts with the correct sub-model, wheel diameter, and the kind of driving character and appearance you want to preserve.
Which Tire Size Is Right for The 2012 Infiniti M56
Two primary tire sizes apply to the 2012 Infiniti M56, and the correct choice depends on sub-model and wheel diameter. The Luxury and X models use an 18-inch radial fitment, while the Sport uses a 20-inch radial fitment. Before choosing a tire, confirm whether the car is a Luxury, Sport, or X and verify that the wheels on the car still match the original diameter for that version.
245/50R18 is a metric radial size in which 245 identifies the nominal section width in millimeters, 50 is the aspect ratio, R indicates radial construction, and 18 is the rim diameter in inches. On the 2012 Infiniti M56, this size is used on 18-inch wheel applications rather than the Sport model’s larger 20-inch setup. Current choices in this fitment center on Pro-Trac Street Pro III tires with either RWL or redline sidewall styling. It is the right size to evaluate when keeping the car on its 18-inch wheel package and choosing between a more understated or more custom visual presentation.
245/40R20 is also a metric radial size, with the same 245-millimeter nominal width but a lower 40-series profile on a 20-inch rim. This fitment belongs to the 2012 Infiniti M56 Sport, making wheel diameter confirmation especially important before selecting tires. Available choices include blackwall performance-oriented options from BFGoodrich and Nitto, along with Pro-Trac Street Pro III tires in RWL and redline versions. This size is the one to consider when the car retains its Sport-model wheel setup and the goal is to balance appearance, rim-width compatibility, and the character of the available tire lines.
Tire fitment for the 2012 Infiniti M56 is not the same across every sub-model. The first step is identifying whether the car is a Luxury, Sport, or X, because that determines both the tire size and the wheel diameter that need to be matched.
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2012 Infiniti M56 Luxury
The 2012 Infiniti M56 Luxury uses the 245/50R18 radial tire size on an 18-inch wheel. Tire selection here is less about choosing between sizes and more about staying with the correct wheel diameter while deciding which sidewall style best suits the car’s appearance.
The 2012 Infiniti M56 Sport uses the lower-profile 245/40R20 radial size on a 20-inch wheel. That makes wheel confirmation essential before purchase, and it opens up a broader mix of blackwall, RWL, and redline tire choices depending on how performance-oriented or visually distinctive the car is meant to be.
The 2012 Infiniti M56 X uses the same 245/50R18 radial tire size as the Luxury model. The practical decision is choosing a tire that matches the existing 18-inch wheel setup and the overall look you want, rather than sorting through multiple primary fitments.
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 2012 Infiniti M56 Tires for Sale
Available 2012 Infiniti M56 tires vary by sub-model, wheel diameter, brand, series, and sidewall style. The 18-inch fitment is centered on Pro-Trac Street Pro III in RWL or redline form, while the 20-inch Sport fitment adds BFGoodrich and Nitto blackwall performance options alongside Pro-Trac choices.
These FAQs focus on the exact tire sizes used on the 2012 Infiniti M56, how fitment changes by sub-model, and what to compare when choosing among 18-inch and 20-inch radial tire options.
Tire Size & Fitment
What tire size fits a 2012 Infiniti M56?
The 2012 Infiniti M56 uses two tire sizes, depending on sub-model. The Luxury and X models use 245/50R18 radial tires, while the Sport uses 245/40R20 radial tires. Both are modern metric radial fitments, but they are not interchangeable primary sizes because they mount to different wheel diameters.
The first thing to confirm is which version of the M56 you have and whether it still carries its original wheel setup. A car that has been fitted with different wheels by a previous owner may no longer match the original sub-model fitment, so checking the actual wheel diameter before choosing tires avoids ordering the wrong size.
What size rim does a 2012 Infiniti M56 use?
A 2012 Infiniti M56 uses either an 18-inch or 20-inch rim, depending on the sub-model. The Luxury and X use 18-inch wheels with 245/50R18 tires, while the Sport uses 20-inch wheels with 245/40R20 tires. The tire size and rim diameter need to match exactly.
Wheel diameter is the most important fitment checkpoint on this car because the two original tire sizes belong to two different wheel packages. Looking at the sidewall size marking helps, but measuring or confirming the wheel itself is smarter when the car has aftermarket wheels, replacement wheels, or a mixed set from a previous ownership period.
Do all 2012 Infiniti M56 sub-models use the same tire size?
No, the 2012 Infiniti M56 does not use one tire size across all sub-models. The Luxury and X share 245/50R18, but the Sport uses 245/40R20. That means tire selection is tied directly to the specific version of the car rather than the model name alone.
This matters because the size difference is not just a small variation in profile; it also changes the wheel diameter from 18 to 20 inches. Anyone replacing tires should identify the exact sub-model first, then verify the wheels currently on the car, especially if the vehicle has seen wheel swaps, suspension changes, or custom appearance updates.
Choosing the Right Tire
What should I consider when choosing a tire for a 2012 Infiniti M56?
Start with the correct sub-model and wheel diameter, because the 2012 Infiniti M56 uses either 245/50R18 or 245/40R20 depending on version. After that, compare the construction, sidewall treatment, tire series, and any available rim-width or load details that matter for the way the car is driven and presented.
An M56 kept close to its original luxury-sedan character may call for a different visual approach than one with a more custom or performance-oriented look. It also helps to confirm that the wheels are the correct width for the tire being considered, and to make sure any replacement still clears the fenders and suspension on the car’s current setup.
What sidewall styles are available for 2012 Infiniti M56 tires?
Sidewall style depends on the tire size and product line chosen for the 2012 Infiniti M56. Available styles include blackwall, RWL, and redline. The 18-inch 245/50R18 fitment is offered in RWL and redline through Pro-Trac Street Pro III, while the 20-inch 245/40R20 Sport fitment adds blackwall options from BFGoodrich and Nitto.
That gives the M56 owner a real appearance decision rather than just a size decision. Blackwall usually keeps the look more understated, while RWL and redline create a stronger visual statement. The best choice depends on whether the car is being kept close to a subtle luxury-sport presentation or styled with more custom influence.
What brands offer tires for the 2012 Infiniti M56?
Tires for the 2012 Infiniti M56 are available from Pro-Trac, BFGoodrich, and Nitto. Brand availability depends on size: the 245/50R18 fitment centers on Pro-Trac Street Pro III, while the 245/40R20 fitment includes BFGoodrich g-Force series options, Nitto NT555 G2, and Pro-Trac Street Pro III choices.
The practical takeaway is that the 20-inch Sport fitment gives a wider spread of product character, while the 18-inch fitment is more focused on sidewall appearance within one series. Choosing among brands should still begin with correct size and wheel compatibility, then move to the look and specification details that matter most for the car’s intended use.
Restoration & Appearance
Which tire should I choose for a period-style 2012 Infiniti M56?
A period-style 2012 Infiniti M56 tire choice starts with keeping the original sub-model size intact: 245/50R18 for Luxury and X, or 245/40R20 for Sport. From there, the visual direction matters. Blackwall options keep the presentation closer to a restrained modern luxury sedan, while RWL and redline choices add a more customized look.
Because this is a modern performance luxury car rather than a mid-century restoration vehicle, appearance decisions are usually more about taste than strict originality. Owners trying to match an early-2010s showroom feel should compare sidewall treatment carefully and avoid assuming that every tire offered in the correct size reflects the car’s original delivery appearance.
How does tire construction affect the appearance of a restored 2012 Infiniti M56?
On a 2012 Infiniti M56, construction is straightforward because the primary fitments are radial tires. The more noticeable appearance change comes from the tire’s sidewall treatment and overall profile within the correct size, especially on the 20-inch Sport setup where the lower-profile tire already gives the car a sharper visual stance.
For a clean restoration-oriented result, keeping the proper size for the sub-model matters more than changing construction type. A Luxury or X model on 18-inch tires presents differently from a Sport on 20s, so preserving that original wheel-and-tire relationship is one of the biggest factors in maintaining the car’s intended visual character.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2012 Infiniti M56?
Yes, modifications can affect tire fitment on a 2012 Infiniti M56 even when the tire size itself seems correct. Aftermarket wheels, changes in wheel width or offset, suspension lowering, and body modifications can all alter how a 245/50R18 or 245/40R20 tire sits in the wheel opening and how much clearance remains in motion.
That is especially important on the Sport model’s 20-inch setup, where wheel and profile changes can become visually and mechanically obvious more quickly. Any M56 with non-original wheels or suspension should be checked for steering clearance, fender clearance, and inner-suspension clearance before settling on a replacement tire in the original size.
What should I inspect before driving a 2012 Infiniti M56 on new tires?
Before driving a 2012 Infiniti M56 on new tires, inspect the wheels for damage, confirm the tire size matches the sub-model, and make sure the tires are mounted on the correct wheel diameter. It also helps to check inflation pressure, valve stems, lug torque, and the overall condition of suspension and alignment-related components.
A short, careful road test is a smart follow-up after installation. Listen for rubbing, feel for vibration, and look again for any sign of contact at full steering lock or over suspension movement. Even with the correct size, worn suspension parts or altered wheels can create problems that only show up once the car is back on the road.
How often should tires on a 2012 Infiniti M56 be inspected?
Tires on a 2012 Infiniti M56 should be inspected regularly, not just when tread looks worn. A monthly check is a sensible routine for pressure, visible damage, uneven wear, and any sign of cuts, bulges, or cracking. Cars that are driven infrequently still need inspection because age and storage conditions can affect tire condition.
A performance luxury sedan with 18-inch or 20-inch fitment can hide problems until ride quality or handling begins to change, so early inspection matters. It is also worth checking before longer trips, after seasonal storage, or anytime the car develops vibration or pulls to one side, since those signs can point to tire or alignment issues.
