The 2003 Infiniti Q45 came from the final years of Infiniti’s flagship rear-wheel-drive luxury sedan, blending V8 prestige, long-wheelbase comfort, and a distinctly modern early-2000s performance-touring character. For tire selection, that matters because this Q45 does not use one universal setup across every version. The Base model uses 225/55R17 radial tires, while the Q45 w/Premium Pkg. uses 245/45R18 radials. Available choices range from blackwall performance-oriented series to Silvertown Radial whitewall and redline styles in 17-inch fitment. The key step is confirming the exact sub-model and wheel diameter before narrowing the choice by appearance, handling goals, and overall presentation.
Which Tire Size Is Right for The 2003 Infiniti Q45
Two primary tire sizes apply to the 2003 Infiniti Q45, and the right one depends on the exact sub-model and wheel diameter. The Base model uses a 17-inch radial setup, while the Q45 w/Premium Pkg. uses an 18-inch radial setup. Before comparing brands or sidewall styles, confirm whether the car is on its original package and verify the wheel size currently installed.
225/55R17 is a metric radial size in which 225 identifies the nominal section width in millimeters, 55 is the aspect ratio, R indicates radial construction, and 17 is the wheel diameter in inches. On the 2003 Infiniti Q45, this size belongs to the Base model and reflects a modern radial fitment rather than a vintage numeric or alphanumeric system. Product choices include BFGoodrich options in g-Force Comp 2 AS, g-Force Sport Comp 2, g-Force Phenom T/A, and Silvertown Radial, with blackwall, wide whitewall, and redline sidewall treatments. This size suits buyers who need the 17-inch Q45 setup and want to choose between contemporary performance styling and a more distinctive appearance.
245/45R18 is a metric radial size where 245 is the nominal section width in millimeters, 45 is the aspect ratio, R designates radial construction, and 18 is the wheel diameter in inches. On the 2003 Infiniti Q45, this size is used on the w/Premium Pkg. configuration, making wheel confirmation essential before selection. Available products include BFGoodrich g-Force Comp 2 AS, g-Force Sport Comp 2, g-Force Phenom T/A, and the Nitto NT555 G2, all in blackwall form. This size is the right path for buyers matching the 18-inch package and comparing modern performance-oriented series within the correct fitment.
Sub-model fitment matters on the 2003 Infiniti Q45 because tire size changes with the wheel package. The Base and w/Premium Pkg. versions use different rim diameters, so identifying the exact sub-model is the first step before comparing tires.
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2003 Infiniti Q45 Base
The 2003 Infiniti Q45 Base uses a 225/55R17 radial tire on a 17-inch wheel package. That keeps the tire search focused on choosing among blackwall, whitewall, or redline 17-inch options rather than sorting through multiple primary sizes.
The 2003 Infiniti Q45 w/Premium Pkg. uses a 245/45R18 radial tire on an 18-inch setup. Tire selection here centers on confirming the 18-inch wheel package and then comparing the available blackwall performance-oriented series within that 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 2003 Infiniti Q45 Tires for Sale
Available Q45 tire choices center on 225/55R17 and 245/45R18 radial fitments from BFGoodrich and Nitto. Buyers can compare blackwall performance series across both sizes, while the 17-inch setup also includes Silvertown Radial options with wide whitewall and redline sidewall styling.
Q45 owners usually need to sort out the correct sub-model, wheel diameter, and tire size first, then compare radial product choices by series, sidewall style, and intended use. These answers focus on the specific fitment questions that matter for a 2003 Infiniti Q45.
Tire Size & Fitment
What tire size fits a 2003 Infiniti Q45?
The 2003 Infiniti Q45 uses two different tire sizes depending on the sub-model. The Q45 Base uses 225/55R17 radial tires, while the 2003 Infiniti Q45 w/Premium Pkg. uses 245/45R18 radial tires. Both are modern metric radial fitments, but they are tied to different wheel diameters.
The most important step is confirming which version of the car is being fitted and checking the wheel diameter currently on the vehicle. A Q45 that has had wheel changes over the years may not still be using its original package, so matching the tire to the actual wheel is just as important as matching the year and model.
What size rim does a 2003 Infiniti Q45 use?
A 2003 Infiniti Q45 uses either a 17-inch or 18-inch rim, depending on the sub-model. The Base model uses a 17-inch wheel with 225/55R17 tires, and the w/Premium Pkg. uses an 18-inch wheel with 245/45R18 tires. The tire size and wheel diameter move together on this application.
Checking wheel diameter should come before comparing tread design, brand, or sidewall style. Looking at the size already mounted on the car, or measuring the wheel if there is any doubt, helps prevent buying a tire built for the wrong rim diameter. Wheel width should also be checked against the tire’s approved rim-width range before final selection.
Do all 2003 Infiniti Q45 sub-models use the same tire size?
No. The 2003 Infiniti Q45 Base uses 225/55R17, while the 2003 Infiniti Q45 w/Premium Pkg. uses 245/45R18. That means the Q45 does not have one universal tire size across every covered sub-model, even though both versions use radial construction.
That difference affects more than the sidewall profile because it also changes the wheel diameter from 17 inches to 18 inches. Buyers should confirm the sub-model first, then verify the wheels actually on the car, especially if the vehicle has been altered by a previous owner. Once that is settled, product choice becomes much more straightforward.
Choosing the Right Tire
What should I consider when choosing a 2003 Infiniti Q45 tire?
Start with the exact size that matches the car’s sub-model: 225/55R17 for the Base model or 245/45R18 for the w/Premium Pkg. After that, compare radial construction details such as tire series, sidewall style, approved rim-width range, and any load figures that are relevant to the way the car is used.
A buyer choosing for appearance may focus on the 17-inch Silvertown Radial options with wide whitewall or redline styling, while a buyer focused on a contemporary blackwall look may compare the available g-Force or Nitto series. Keeping the selection tied to the actual wheel diameter and intended use helps narrow the field quickly.
What sidewall styles are available for 2003 Infiniti Q45 tires?
Sidewall style depends on the tire size. In 225/55R17, the available choices include blackwall, wide whitewall, and redline. In 245/45R18, the available products are blackwall. That means the 17-inch Base fitment offers the broader appearance range, while the 18-inch Premium Package fitment stays focused on a modern blackwall presentation.
That distinction can shape the entire look of the car. A blackwall tire keeps the Q45 closer to a contemporary luxury-sedan appearance, while whitewall or redline treatment creates a more customized or specialty presentation. Sidewall style should always be considered after the correct size and wheel package have been confirmed.
What brands offer tires for the 2003 Infiniti Q45?
BFGoodrich offers tires in both Q45 sizes, including several g-Force series and Silvertown Radial in the 17-inch fitment. Nitto appears in the 245/45R18 size with the NT555 G2. Brand choice on this application is therefore tied partly to which wheel package the car uses.
Comparing brands makes the most sense once the correct size is settled. In 225/55R17, BFGoodrich covers both performance-oriented blackwall options and more appearance-driven Silvertown Radial choices. In 245/45R18, the comparison is between blackwall performance-style offerings, so series characteristics, rim-width compatibility, and the car’s intended use become the next filters.
Restoration & Appearance
Which tire should I choose for a period-style 2003 Infiniti Q45?
A period-style 2003 Infiniti Q45 tire choice starts with the correct size for the sub-model, then moves to sidewall appearance. The Base model’s 225/55R17 fitment offers the widest visual range because it includes blackwall, wide whitewall, and redline options. The w/Premium Pkg. 245/45R18 fitment stays in blackwall form.
That means appearance-driven buyers with the 17-inch setup have more room to shape the car’s look without changing the primary size. Buyers aiming for a strictly era-appropriate result should compare the tire choice against original vehicle literature, period photos, or marque-specific references, since sidewall treatment alone does not prove factory originality.
How does tire construction affect the appearance of a restored 2003 Infiniti Q45?
On the 2003 Infiniti Q45, the primary fitments are radial tires in both available sizes, so the main appearance difference comes less from construction type and more from sidewall treatment and series character. In practical terms, blackwall tires deliver the most modern presentation, while the 17-inch whitewall and redline options create a more distinctive visual statement.
A restored or preserved Q45 can look notably different depending on that choice, even when the size remains correct. Matching the tire to the wheel diameter and sub-model should come first, then the sidewall style can be used to support the owner’s preferred presentation, whether that leans understated, custom, or more visually traditional.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2003 Infiniti Q45?
Yes. A 2003 Infiniti Q45 may no longer be on its original wheel and tire package, and changes such as aftermarket wheels, altered wheel width, offset changes, or suspension modifications can affect what fits properly. That matters especially here because the car already has two factory-style size paths tied to different wheel diameters.
Checking the actual wheel diameter and width on the car is the first step before choosing between 225/55R17 and 245/45R18. Steering clearance, fender space, and suspension condition should also be reviewed when the car has been lowered or otherwise changed. Fitment should be confirmed against the current setup, not just the model year alone.
What should I inspect before driving a 2003 Infiniti Q45 on new tires?
Before driving a 2003 Infiniti Q45 on new tires, inspect the wheels for damage, confirm that the tire size matches the wheel diameter, and make sure inflation is set correctly for the tires being installed. It is also wise to check for uneven wear patterns that could point to alignment or suspension issues needing attention.
A road-ready inspection should also include looking at brake clearance, steering movement at full lock, and overall tire-to-fender space once the car is on the ground. Older luxury sedans can hide worn bushings or tired suspension parts, so a short test drive followed by another visual check helps catch rubbing, vibration, or air-loss issues early.
How often should tires on a 2003 Infiniti Q45 be inspected?
Tires on a 2003 Infiniti Q45 should be inspected regularly, not just when they look low or worn. Monthly pressure checks and routine visual inspections for cracking, bulges, cuts, punctures, and uneven tread wear are sensible practice, especially on a vehicle that may spend long periods parked between drives.
Collector-minded or low-mileage use can make age and storage condition just as important as tread depth. Looking over the tires before longer drives helps catch air loss or sidewall issues before they become roadside problems. The same routine should include checking that the wheel and tire combination still matches the car’s intended setup.
