The 2018 BMW 640i xDrive Gran Turismo blends luxury fastback styling with the long-distance comfort and all-weather confidence expected from BMW’s grand touring lineup. It sits in a modern space where wheel and tire selection affects not just appearance, but also balance between ride quality, handling, and stance. This model uses radial tire fitments in both 19-inch and 20-inch combinations, with separate front and rear sizes on staggered setups. Available choices include blackwall performance tires along with raised white letter and redline options in the 20-inch sizes. The key is confirming whether the car is on the 19-inch package or the staggered 20-inch package before comparing tire styles and series.
Which Tire Size Is Right for The 2018 BMW 640i xDrive Gran Turismo
The 2018 BMW 640i xDrive Gran Turismo uses four primary tire sizes, split between 19-inch and 20-inch wheel packages. Some configurations use a single 245/45R19 size, while others use staggered front and rear fitments with different widths. Confirming the exact wheel diameter and whether the car has a square or staggered setup is the first step before choosing a tire.
245/45R19 is a metric radial size in which 245 identifies the nominal section width in millimeters, 45 is the aspect ratio, and 19 is the rim diameter in inches. On this BMW, it serves as a 19-inch fitment and can appear as the single tire size on the Base model or as the front size in a 19-inch front and rear pairing. Available options center on blackwall radial performance tires from BFGoodrich and Nitto across g-Force and NT555 series choices. This size is the one to evaluate when the car retains its 19-inch front setup and a modern blackwall presentation is the goal.
245/40R20 is a metric radial size with a 245-millimeter nominal section width, a 40-series profile, and a 20-inch rim diameter. It is used as the front tire size on the 20-inch staggered setup for the 2018 BMW 640i xDrive Gran Turismo. Product choices include blackwall offerings from BFGoodrich and Nitto, plus Pro-Trac Street Pro III versions with raised white letter and redline sidewalls for a more customized look. This is the right front size to consider when the car is equipped with 20-inch wheels and the buyer wants either a straightforward performance appearance or a more distinctive sidewall treatment.
275/35R20 is a metric radial size where 275 is the nominal section width in millimeters, 35 is the aspect ratio, and 20 is the rim diameter. On this BMW, it functions as the rear tire in the 20-inch staggered arrangement, adding width compared with the matching 245/40R20 front size. Available products include blackwall tires from BFGoodrich and Nitto, along with Pro-Trac Street Pro III options in raised white letter and redline form. This size matters when maintaining the intended staggered 20-inch setup, since rear width, wheel match, and overall appearance all come into play.
275/40R19 is a metric radial size with a 275-millimeter nominal section width, a 40-series aspect ratio, and a 19-inch rim diameter. It is used as the rear size in the 19-inch front and rear pairing, complementing the narrower 245/45R19 front tire. The available choices are 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 lines. This is the rear size to compare when the car runs the wider 19-inch rear setup and the priority is keeping the correct front-to-rear relationship on that wheel package.
Sub-model fitment matters on the 2018 BMW 640i xDrive Gran Turismo because the tire setup can be either a single-size 19-inch arrangement or a staggered front and rear combination. Checking whether the car is identified as Base, Base Front, or Base Rear helps narrow the correct size before comparing products.
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2018 BMW 640i xDrive Gran Turismo Base
The Base configuration uses 245/45R19 radial tires. That makes tire selection more straightforward, with the focus shifting to 19-inch wheel confirmation and choosing among the available blackwall performance tire series.
The Base Front fitment covers the front axle sizing used with either the 19-inch or 20-inch setup. Tire choice here depends on confirming which wheel package is on the car, since the front size changes with the rim diameter.
The Base Rear fitment covers the rear axle sizing for the two supported wheel packages, with a wider rear tire than the front in staggered arrangements. Selecting the correct rear tire means matching the existing wheel diameter and preserving the intended front-to-rear size relationship.
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 2018 BMW 640i xDrive Gran Turismo Tires for Sale
Available 2018 BMW 640i xDrive Gran Turismo tires center on radial performance choices from BFGoodrich, Nitto, and Pro-Trac. Depending on size, buyers can compare blackwall tires across several series, while the 20-inch fitments also add raised white letter and redline sidewall options.
Common questions for the 2018 BMW 640i xDrive Gran Turismo usually come down to identifying the correct 19-inch or 20-inch setup, understanding staggered front and rear sizing, and comparing available radial tire styles, brands, and maintenance considerations.
Tire Size & Fitment
What tire size fits a 2018 BMW 640i xDrive Gran Turismo?
The 2018 BMW 640i xDrive Gran Turismo uses 245/45R19, 245/40R20, 275/35R20, and 275/40R19 tire sizes. The 19-inch setup uses 245/45R19 at the front and 275/40R19 at the rear, while the 20-inch setup uses 245/40R20 at the front and 275/35R20 at the rear. A Base configuration may also appear with 245/45R19 as the primary size.
The practical step is identifying whether the car has 19-inch wheels or 20-inch wheels, and whether it is using a staggered front and rear combination. Matching the existing wheel diameter and axle position matters before comparing brands, sidewall treatments, or tire series.
What size rim does a 2018 BMW 640i xDrive Gran Turismo use?
The 2018 BMW 640i xDrive Gran Turismo uses both 19-inch and 20-inch rim diameters, depending on the wheel package. The 245/45R19 and 275/40R19 sizes mount on 19-inch rims, while the 245/40R20 and 275/35R20 sizes mount on 20-inch rims. All of the primary fitments are radial tires.
Rim diameter should be confirmed before anything else because a 19-inch tire cannot be mounted on a 20-inch wheel, and vice versa. Once wheel diameter is verified, the next check is whether the car uses the narrower front size, the wider rear size, or a single-size 19-inch arrangement.
Why does the 2018 BMW 640i xDrive Gran Turismo have more than one tire size?
More than one tire size applies because the 2018 BMW 640i xDrive Gran Turismo was fitted with different wheel packages, including both 19-inch and 20-inch combinations. It also uses staggered sizing in front and rear pairings, so the front axle and rear axle do not necessarily share the same width or profile.
That means the correct choice is tied to the actual wheels on the car rather than the model name alone. Looking at the existing tire sidewalls and confirming whether the vehicle is on a 19-inch or 20-inch setup will prevent selecting a front tire for the rear, or mixing sizes from different packages.
Choosing the Right Tire
What should I consider when choosing a 2018 BMW 640i xDrive Gran Turismo tire?
Start with the correct size for the exact wheel package on the car, since this BMW uses both 19-inch and 20-inch fitments and may also use staggered front and rear sizing. From there, compare radial tire series, brand options, sidewall style where available, and any useful specification differences such as rim-width range or load capacity details.
A buyer focused on preserving the current look may stay with a blackwall performance tire, while someone seeking a more custom presentation may look closely at the 20-inch raised white letter or redline options. Wheel diameter, axle position, and intended road use should all be settled before narrowing the final choice.
What sidewall styles are available for 2018 BMW 640i xDrive Gran Turismo tires?
Blackwall is the most common sidewall style across the available 2018 BMW 640i xDrive Gran Turismo tire sizes. In the 20-inch 245/40R20 and 275/35R20 sizes, there are also Pro-Trac Street Pro III options with raised white letter sidewalls and redline sidewalls, giving the buyer more visual variety than the 19-inch selections.
Sidewall style mainly affects appearance, so the right choice depends on whether the car is being kept understated or given a more personalized look. The important thing is to keep the correct size and wheel diameter first, then compare sidewall treatments only within the fitment that matches the car’s current setup.
What brands offer tires for the 2018 BMW 640i xDrive Gran Turismo?
Tires for the 2018 BMW 640i xDrive Gran Turismo are available from BFGoodrich, Nitto, and Pro-Trac. BFGoodrich appears across multiple g-Force series, Nitto is represented by the NT555 G2 line, and Pro-Trac Street Pro III covers some of the 20-inch fitments with more appearance-driven sidewall choices.
Brand choice should be compared after the correct size is confirmed, since not every brand or series appears in every fitment. A 19-inch rear tire shopper will see a different mix than someone replacing a 20-inch front tire, so it helps to compare choices within the exact axle position and wheel diameter already on the car.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2018 BMW 640i xDrive Gran Turismo?
Yes, modifications can affect tire fitment on a 2018 BMW 640i xDrive Gran Turismo. Aftermarket wheels, changes in wheel width, offset differences, suspension lowering, and body modifications can all change how a 245/45R19, 245/40R20, 275/35R20, or 275/40R19 tire sits in the wheel opening and clears nearby components.
A car that no longer has its original wheel and suspension setup should be checked carefully before replacing tires by size alone. Wheel diameter is only one part of the fitment picture; front-to-rear placement, clearance at full steering lock, and the relationship between tire width and wheel width all matter as well.
What should I inspect before driving a 2018 BMW 640i xDrive Gran Turismo on new tires?
Before road use, inspect wheel condition, valve stems, lug hardware, and basic clearance around the front suspension, inner fenders, and rear wheel openings. Tire pressure should be set correctly for the installed tires, and each tire should be checked for visible defects, bead seating, and any signs of rubbing once mounted.
A short, careful test drive helps confirm that the steering remains smooth and that the tires do not contact suspension or body parts under normal movement. On a staggered setup, it is also smart to double-check that the front sizes stayed on the front axle and the wider rear sizes stayed on the rear.
How often should tires on a 2018 BMW 640i xDrive Gran Turismo be inspected?
Tires on a 2018 BMW 640i xDrive Gran Turismo should be inspected regularly, especially if the car sees seasonal use or spends long periods parked. Look for pressure loss, uneven wear, cuts, punctures, bulges, and sidewall cracking, and pay attention to how the front and rear tires are wearing if the car uses a staggered arrangement.
Routine checks matter because luxury grand touring cars can hide tire issues until vibration, noise, or handling changes appear on the road. A monthly visual inspection, plus a closer look before longer drives, helps catch aging or wear issues early and confirms that the current tires still suit the wheel package on the car.
