The 2008 Infiniti M45 sits in the era when Infiniti blended V8 luxury-sport performance with sharp sedan styling and a more driver-focused feel than many traditional full-size luxury cars. Buyers looking at this exact car are usually balancing road manners, stance, and wheel fitment rather than chasing a vintage-style bias-ply presentation. Tire fitment for the 2008 Infiniti M45 is radial only, with 245/45R18 and 245/40R19 sizes tied to specific sub-models and wheel diameters. Available choices center on blackwall performance-oriented radial tires from BFGoodrich and Nitto across several g-Force and NT555 series options. The key is matching the tire to the correct sub-model and wheel setup before comparing tread style, series, and load-focused specifications.
Which Tire Size Is Right for The 2008 Infiniti M45
The 2008 Infiniti M45 uses two primary tire sizes, and the correct one depends on the exact sub-model and wheel diameter. Base and X models use an 18-inch setup with 245/45R18, while the Sport uses a 19-inch setup with 245/40R19. Before choosing a tire, confirm whether the car is a Base, Sport, or X and verify that the wheels on the car still match that original diameter.
A 245/45R18 tire uses a 245-millimeter nominal section width, a 45-series aspect ratio, radial construction, and an 18-inch rim diameter. On the 2008 Infiniti M45, this is a modern radial fitment used on the Base and X models, making it the right starting point for cars on the standard 18-inch wheel setup. Available choices include BFGoodrich and Nitto blackwall tires in series such as g-Force Comp 2 AS, g-Force Sport Comp 2, g-Force Phenom T/A, and NT555 G2. This size makes the most sense when the car retains its 18-inch wheels and the goal is choosing among performance-oriented radial options within the correct fitment.
A 245/40R19 tire keeps the same 245-millimeter nominal width but uses a lower 40-series profile on a 19-inch rim. For the 2008 Infiniti M45, this size belongs to the Sport model and reflects its distinct wheel package rather than a universal M45 fitment. Product choices in this size are blackwall BFGoodrich radials, including g-Force Comp 2 AS, g-Force Sport Comp 2, and g-Force Phenom T/A. This is the size to evaluate when the car is a genuine M45 Sport or when the wheel setup has been confirmed as 19 inches front and rear.
Sub-model fitment matters on the 2008 Infiniti M45 because tire size changes with the wheel package. Base and X models share one radial size, while the Sport uses a different size on a different rim diameter, so confirming the exact trim is the first step.
1
2008 Infiniti M45 Base
The 2008 Infiniti M45 Base uses the 245/45R18 radial size on an 18-inch wheel setup. That keeps tire selection focused on choosing among the available blackwall performance radials while confirming that the car has not been changed to a different wheel diameter.
The 2008 Infiniti M45 Sport uses the 245/40R19 radial size, which separates it clearly from the other M45 sub-models. Tire selection starts with confirming the 19-inch Sport wheel setup, then comparing the available BFGoodrich blackwall radial series in that size.
The 2008 Infiniti M45 X uses the same 245/45R18 radial tire size as the Base model. That means the main decision is not between multiple primary sizes, but between the available 18-inch tire series, construction details, and wheel-compatibility specifications.
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 2008 Infiniti M45 Tires for Sale
Available 2008 Infiniti M45 tires center on 245/45R18 and 245/40R19 blackwall radials from BFGoodrich and Nitto. The product grid lets you compare g-Force and NT555 series options by size, wheel-width compatibility, load figures where stated, and overall product character.
Owners shopping for 2008 Infiniti M45 tires usually need to confirm the correct sub-model first, then compare 18-inch versus 19-inch fitment, available radial tire series, and practical checks for wheel setup, maintenance, and road use.
Tire Size & Fitment
What tire size fits a 2008 Infiniti M45?
The 2008 Infiniti M45 uses two primary tire sizes: 245/45R18 and 245/40R19. The Base and X models use 245/45R18, while the Sport uses 245/40R19, and both are radial fitments rather than vintage bias-ply sizes.
The practical difference is that these sizes also use different wheel diameters, so the first thing to confirm is the exact sub-model and the actual wheels on the car. A car that has been changed from 18-inch to 19-inch wheels, or vice versa, should be checked carefully before selecting a tire.
What size rim does a 2008 Infiniti M45 use?
A 2008 Infiniti M45 uses either an 18-inch or 19-inch rim, depending on the sub-model. The Base and X models use the 245/45R18 tire size on an 18-inch wheel, while the Sport uses the 245/40R19 size on a 19-inch wheel.
That makes rim diameter just as important as tire size when replacing tires on this car. Checking the sidewall marking on the current tires helps, but the wheel itself should also be verified, especially if the car has aftermarket wheels or a previous owner changed the original setup.
Do all 2008 Infiniti M45 sub-models use the same tire size?
No. The 2008 Infiniti M45 Base and M45 X share the 245/45R18 radial size, but the M45 Sport uses 245/40R19. Even though both sizes carry the same nominal 245-millimeter width, they are not the same fitment because the profile and rim diameter differ.
That means tire shopping should start with trim identification rather than brand comparison. Once the sub-model is confirmed, you can focus on the correct wheel diameter and then compare the available radial tire series, blackwall designs, and wheel-width specifications within that specific size.
Choosing the Right Tire
What should I consider when choosing a 245/45R18 tire for a 2008 Infiniti M45?
Start by confirming that the car is a 2008 Infiniti M45 Base or X and that it still uses 18-inch wheels. In this size, available radial choices include BFGoodrich and Nitto options, all in blackwall form, with differences in tire series, stated load figures on some products, and compatible wheel-width ranges.
Selection usually comes down to matching the tire to the car's actual wheel width and intended use. A sedan driven mostly on fair-weather roads may be evaluated differently than one used year-round, and it is worth comparing rim-width guidance, sidewall condition needs, and overall product character rather than choosing by size alone.
What brands offer tires for the 2008 Infiniti M45?
BFGoodrich and Nitto offer tires for the 2008 Infiniti M45 in the sizes used by this car. BFGoodrich appears in both 245/45R18 and 245/40R19, while Nitto is available in 245/45R18 for the 18-inch fitment used on the Base and X models.
Brand choice should come after fitment is settled. The more important comparison points are the exact size, wheel diameter, compatible rim-width range, and the tire series itself, since those factors shape whether the tire suits an 18-inch Base or X setup or the separate 19-inch Sport configuration.
What tire series are available for the 2008 Infiniti M45?
The 2008 Infiniti M45 is offered with several modern radial tire series, including BFGoodrich g-Force Comp 2 AS, g-Force Sport Comp 2, g-Force Phenom T/A, and the Nitto NT555 G2. These series appear across the 18-inch and 19-inch fitments used by the M45 lineup.
Comparing series is useful once the correct tire size has been confirmed. One series may only be available in the 18-inch fitment, while others span both sizes, so the buyer should compare the exact application, sidewall style, rim-width compatibility, and any stated load specifications rather than assuming every series applies to every sub-model.
Restoration & Appearance
Which tire should I choose for a period-style 2008 Infiniti M45?
A period-style approach for a 2008 Infiniti M45 still begins with the correct modern radial size for the exact sub-model. That means 245/45R18 for the Base and X or 245/40R19 for the Sport, paired with the car's original wheel diameter rather than a vintage-style construction change.
Appearance choices are more restrained here than on an older collector car because the available tires are blackwall performance radials. For an owner trying to preserve the sedan's original era feel, the safest path is keeping the correct size and rim diameter first, then choosing among the available performance-oriented series.
Does correct tire fitment matter for a 2008 Infiniti M45 restoration?
Yes, correct tire fitment matters because the 2008 Infiniti M45 uses two distinct size-and-wheel combinations depending on sub-model. A Base or X on 245/45R18 presents differently from a Sport on 245/40R19, so the tire size is part of the car's intended overall stance and wheel relationship.
A restoration-minded owner should confirm the exact trim, verify whether the wheels are original-type diameters, and avoid treating 18-inch and 19-inch setups as interchangeable. When originality matters closely, period photos, original sales literature, and marque-specific references can help confirm whether the current wheel-and-tire package matches the car's intended specification.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2008 Infiniti M45?
Yes. Wheel changes, suspension lowering, altered offset, and previous tire substitutions can all affect tire fitment on a 2008 Infiniti M45. That matters especially here because the car already has two factory-style wheel diameters across the model range, so an incorrect assumption about trim can lead to choosing the wrong size.
A modified car should be checked at the wheel itself rather than relying only on the badge or trim name. Clearance at the fender, inner wheelhouse, and steering range should be reviewed, and the actual wheel width should be compared with the tire's approved range before settling on a replacement.
What should I inspect before driving a 2008 Infiniti M45 on new tires?
Before driving a 2008 Infiniti M45 on new tires, inspect the wheels for damage, confirm the tire size matches the sub-model and rim diameter, and make sure the tires are inflated properly for the vehicle's setup. It is also smart to check for suspension wear, alignment issues, and any signs of rubbing from prior tire use.
A short, careful road test helps confirm that the steering feels normal and that there is no contact during turns or over bumps. Tire pressure should be rechecked after installation, and lug torque, valve condition, and general ride behavior deserve attention before putting the car into regular service.
How often should tires on a 2008 Infiniti M45 be inspected?
Tires on a 2008 Infiniti M45 should be inspected regularly, not just when tread looks low. Even on a newer-style performance sedan, age, curb impact, road hazards, and underinflation can affect tire condition before wear becomes obvious, especially if the car is driven infrequently or stored for long periods.
Routine checks should look for uneven tread wear, cuts, bulges, cracking, and slow air loss. A car with 18-inch Base or X fitment should still be monitored differently from a 19-inch Sport setup if wheel damage or ride harshness is a concern, so inspection should include both tire condition and wheel condition together.
