The 2015 BMW 550i GT blends grand-touring comfort with the long-roof, hatchback practicality that set the 5 Series Gran Turismo apart from a conventional sedan. Its tire fitment is more involved than a single-size replacement because this model uses several radial sizes across 18-inch, 19-inch, and 20-inch wheel packages, including staggered front-and-rear setups on some configurations. That means the real decision is not just choosing a tire, but confirming the exact sub-model and wheel diameter first. Once that is settled, the available choices range from blackwall performance-oriented radials to RWL and redline treatments that change the car's presentation.
Which Tire Size Is Right for The 2015 BMW 550i GT
The 2015 BMW 550i GT uses five primary tire sizes, and the correct one depends on the exact sub-model and wheel package. Fitment varies by 18-inch, 19-inch, and 20-inch rims, and some versions use staggered front-and-rear sizing, so the first step is confirming both the sub-model and the wheel diameter before comparing tire choices.
245/50R18 is a metric radial size in which 245 identifies the section width in millimeters, 50 is the aspect ratio, R denotes radial construction, and 18 is the rim diameter in inches. On the 2015 BMW 550i GT, this size suits 18-inch wheel applications and keeps the selection focused on modern radial construction. Available choices include Pro-Trac Street Pro III versions with either RWL or redline sidewall treatment. This size is the one to evaluate when the car is equipped with the 18-inch setup and appearance preference matters alongside basic fitment.
245/45R19 follows the same metric radial format, with a 245-millimeter section width, a 45-series profile, radial construction, and a 19-inch rim. For the 2015 BMW 550i GT, this is one of the key 19-inch fitments and appears on more than one sub-model configuration. Product choices include blackwall performance-oriented options from BFGoodrich and Nitto across series such as g-Force Comp 2 AS, g-Force Phenom T/A, and NT555 G2. This size deserves close attention if the car runs a square 19-inch setup or uses 19-inch front fitment within a staggered package.
245/40R20 is a lower-profile metric radial size with a 245-millimeter section width, 40-series aspect ratio, radial construction, and a 20-inch rim diameter. On the 2015 BMW 550i GT, it serves as a front fitment in 20-inch applications rather than a one-size-fits-all replacement across every configuration. The size is offered in blackwall form from BFGoodrich and Nitto, and in Pro-Trac Street Pro III with RWL or redline styling. It is the size to evaluate when the car has 20-inch front wheels and the buyer wants to balance wheel-package accuracy with sidewall appearance.
275/35R20 is a wider metric radial size, where 275 marks the section width in millimeters, 35 is the aspect ratio, R is radial construction, and 20 is the rim diameter. For the 2015 BMW 550i GT, this size belongs to 20-inch rear applications in staggered setups, so it should be treated as a position-specific fitment. Available options include blackwall choices from BFGoodrich and Nitto plus Pro-Trac Street Pro III in RWL and redline form. This size matters when matching the rear wheel package correctly and preserving the intended staggered tire layout.
275/40R19 is a 19-inch metric radial with a 275-millimeter section width and a 40-series profile, making it broader than the 245-section front sizes paired with some 19-inch applications. On the 2015 BMW 550i GT, it serves as a rear fitment in staggered 19-inch configurations rather than a universal size for every version. Choices center on blackwall radials from BFGoodrich and Nitto, including g-Force Sport Comp 2, g-Force Comp 2 AS, g-Force Phenom T/A, and NT555 G2. This is the size to confirm when the car uses 19-inch rear wheels and a staggered setup.
Sub-model fitment on the 2015 BMW 550i GT is not uniform, because tire size changes with both trim line and wheel package. Checking the exact sub-model matters here, especially where front and rear positions are split between different sizes on staggered 19-inch or 20-inch setups.
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2015 BMW 550i GT Base
The 2015 BMW 550i GT Base uses a straightforward single-size radial fitment on an 18-inch wheel package. Tire selection here is mainly about choosing the right sidewall presentation and confirming that the car still carries its original wheel diameter.
The 2015 BMW 550i GT Luxury Line uses a 19-inch radial fitment rather than the 18-inch base setup. That makes wheel confirmation important before selection, especially if the car has been changed from one factory-style package to another.
The 2015 BMW 550i GT Luxury Line Front uses a 20-inch front radial size as part of a staggered arrangement. Tire choice here should be made alongside the matching rear fitment so the front and rear setup stays consistent with the wheel package.
The 2015 BMW 550i GT Luxury Line Rear uses a wider 20-inch radial size than the corresponding front position. That means rear tire selection should focus on the correct staggered size first, then narrow the options by sidewall style and tire series.
The 2015 BMW 550i GT M Sport can use a 19-inch radial setup, so it should not be assumed to share the 20-inch staggered arrangement found on other M Sport position-specific listings. Wheel diameter is the first thing to verify before comparing product options.
The 2015 BMW 550i GT M Sport Front is tied to front-position fitments that can involve either a 19-inch or 20-inch radial size. That makes exact wheel package confirmation essential before selecting a front tire for appearance, load capability, or tread style.
The 2015 BMW 550i GT M Sport Rear uses wider rear radial sizes that vary between 19-inch and 20-inch wheel packages. Rear selection should match the actual staggered setup on the car, not just the trim name, because both rim diameter and tire size can change.
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 2015 BMW 550i GT Tires for Sale
Available 2015 BMW 550i GT tires span 18-inch, 19-inch, and 20-inch radial sizes from BFGoodrich, Nitto, and Pro-Trac. Depending on size, buyers can compare blackwall performance-oriented series such as g-Force and NT555 G2 alongside Pro-Trac Street Pro III options in RWL or redline.
For the 2015 BMW 550i GT, the most important questions center on identifying the correct size by sub-model and wheel package, then comparing radial tire options, sidewall styles, and practical fitment checks before road use.
Tire Size & Fitment
What tire size fits a 2015 BMW 550i GT?
The 2015 BMW 550i GT uses several tire sizes rather than one universal fitment: 245/50R18, 245/45R19, 245/40R20, 275/35R20, and 275/40R19. All of them are radial sizes, and the correct one depends on the exact sub-model and whether the car uses an 18-inch, 19-inch, or 20-inch wheel package.
The practical first step is confirming the wheel diameter and whether the car has a square setup or a staggered front-and-rear arrangement. On cars that have changed wheels over time, the tire placard, current wheel markings, and actual mounted tire sizes should all be checked before choosing a replacement.
What size rim does a 2015 BMW 550i GT use?
A 2015 BMW 550i GT can use 18-inch, 19-inch, or 20-inch rims depending on the configuration. The 245/50R18 size fits an 18-inch rim, 245/45R19 and 275/40R19 fit 19-inch rims, and 245/40R20 plus 275/35R20 fit 20-inch rims.
Rim diameter should be verified before any tire search goes further, because two tires with similar overall dimensions still will not mount on the wrong wheel diameter. It also helps to confirm whether the car uses matching wheels all around or a staggered setup with narrower fronts and wider rears.
Why does the 2015 BMW 550i GT have more than one tire size?
More than one tire size appears on the 2015 BMW 550i GT because different sub-models use different wheel packages, and some applications split the fitment between front and rear positions. That is why the size range includes both 18-inch and 19-inch square-type fitments as well as wider rear sizes on staggered 19-inch and 20-inch combinations.
That variation means a buyer should not select tires by model name alone. The exact trim, the actual wheels on the car, and the front-versus-rear position all matter, especially on a vehicle that may have been upgraded, modified, or moved from one OEM-style wheel package to another.
Choosing the Right Tire
What should I consider when choosing a 2015 BMW 550i GT tire?
Start with the exact tire size and wheel diameter used on the car, because the 2015 BMW 550i GT spans 18-inch, 19-inch, and 20-inch radial fitments. After size is confirmed, compare construction details such as sidewall style, tire series, rim-width suitability where stated, weight, and any stated load-capacity figures for the size being considered.
The right choice depends on how the car is equipped and how you want it to present visually. A blackwall performance-style radial may suit a modern look, while RWL or redline options can change the character of the car substantially without changing the primary size or wheel diameter.
What sidewall styles are available for 2015 BMW 550i GT tires?
Sidewall choices for the 2015 BMW 550i GT include Blackwall, RWL, and Redline, depending on the tire size. Blackwall appears broadly across the BFGoodrich and Nitto offerings, while certain Pro-Trac Street Pro III sizes are available with either raised white letter or redline sidewall treatment.
That gives the car a meaningful appearance decision even when the primary fitment is already settled. The best approach is to confirm the correct size first, then compare which sidewall treatments are actually offered in that size so style preferences do not lead to a mismatch in wheel diameter or front-rear position.
What brands offer tires for the 2015 BMW 550i GT?
Tires for the 2015 BMW 550i GT are available from BFGoodrich, Nitto, and Pro-Trac. Depending on size, those brands appear in series such as g-Force Comp 2 AS, g-Force Sport Comp 2, g-Force Phenom T/A, NT555 G2, and Street Pro III.
Brand choice should come after the fitment basics are settled. Once the right size is confirmed, comparing brands by sidewall style, series character, rim-width specification where available, and any stated load-capacity details will usually narrow the decision more effectively than choosing by brand name alone.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2015 BMW 550i GT?
Yes. A 2015 BMW 550i GT can be affected by wheel changes, suspension alterations, or any move away from the original 18-inch, 19-inch, or 20-inch wheel package. That matters even more on staggered setups, where the front and rear tires are intentionally different sizes and should not be treated as interchangeable.
Modified cars should be checked for actual wheel diameter, wheel width, tire-to-fender clearance, and steering clearance before replacement tires are chosen. It is also wise to confirm that the current setup has even wear and no rubbing marks, since those clues often reveal fitment problems before new tires are installed.
What should I inspect before driving a 2015 BMW 550i GT on new tires?
Before road use, inspect inflation pressure, wheel fastener torque, tread and sidewall condition, and the basic seating of each tire on the wheel. On a 2015 BMW 550i GT, it is also important to confirm that each tire is mounted in the correct front or rear position when the car uses a staggered arrangement.
A short, careful check for rubbing, vibration, or steering pull should follow the first installation. After a little driving, recheck pressure and look again at inner and outer clearances, especially if the car uses aftermarket wheels or a lower-profile 19-inch or 20-inch setup.
How often should tires on a 2015 BMW 550i GT be inspected?
Tires on a 2015 BMW 550i GT should be inspected regularly, not just when tread looks worn. Routine checks should include pressure, uneven wear, sidewall cracking, cuts, bulges, and any signs of slow air loss, particularly on cars that spend long periods parked between drives.
Regular inspection matters because this model can use low-profile 19-inch and 20-inch tires that make condition changes easier to feel from behind the wheel. A quick visual check before trips, plus a more thorough inspection at service intervals, helps catch wear or clearance issues before they become larger problems.
