The 2021 BMW M240i sits at the sharp end of BMW’s compact rear-wheel-drive performance coupe and convertible formula, blending modern turbocharged power with a chassis that rewards precise setup. It is a car where tire choice has a direct effect on steering response, balance, and the overall feel behind the wheel. This fitment uses staggered 18-inch radial sizing, with 225/40R18 at the front and 245/35R18 at the rear. Available options stay within a blackwall performance look and include several BFGoodrich g-Force selections, along with a Nitto NT555 G2 front fitment. The key is confirming front-versus-rear placement and choosing a tire that matches the car’s intended street use and setup.
Which Tire Size Is Right for The 2021 BMW M240i
The 2021 BMW M240i uses two primary tire sizes, both in radial construction on 18-inch rims. The main decision is identifying whether you are replacing the front or rear tires, since the car uses a staggered setup with different widths and profiles at each end. Once that is confirmed, the focus shifts to comparing the available performance-oriented product choices within the correct size.
Fit(s): Convertible, Convertible Front, Coupe, and Coupe Front
Construction: Radial|Rim: 18 in
225/40R18 is a metric radial size where 225 is the nominal section width in millimeters, 40 is the aspect ratio, R identifies radial construction, and 18 is the wheel diameter in inches. On the 2021 BMW M240i, this size serves the front position in both Coupe and Convertible applications, making it central to steering feel and front-end response. Available choices include BFGoodrich and Nitto blackwall performance tires across series such as g-Force Comp 2 AS, g-Force Sport Comp 2, g-Force Phenom T/A, and NT555 G2. This is the size to evaluate when front tire replacement, matched handling balance, and rim-width compatibility are the main concerns.
245/35R18 is a metric radial size with a 245-millimeter nominal section width, a 35-series profile, radial construction, and an 18-inch rim diameter. On the 2021 BMW M240i, this size is used at the rear, where the wider fitment supports the car’s staggered tire setup and rear-axle traction balance. The available product selection in this size includes a BFGoodrich g-Force Phenom T/A blackwall radial. This is the size to confirm when replacing rear tires, maintaining the intended front-to-rear sizing relationship, or checking wheel width before choosing a performance replacement.
Fitment on the 2021 BMW M240i is straightforward once the exact position is identified, because both Coupe and Convertible use the same staggered sizing pattern. Checking the sub-model still matters because front and rear fitments are separated and should not be treated as interchangeable.
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2021 BMW M240i Convertible
The 2021 BMW M240i Convertible uses the same staggered radial tire layout as the Coupe, with separate front and rear sizes on 18-inch wheels. Tire selection should follow axle position first, then narrow down among the available performance blackwall options in the correct size.
The front fitment for the 2021 BMW M240i Convertible uses the narrower of the two primary sizes and remains part of the car’s staggered radial setup. Front tire selection should focus on keeping the correct size, confirming wheel width, and comparing the available performance-oriented series.
The rear fitment for the 2021 BMW M240i Convertible uses the wider primary size, which is distinct from the front and important to the car’s overall balance. Rear tire replacement should center on preserving that staggered relationship and verifying wheel compatibility before installation.
The 2021 BMW M240i Coupe follows the same staggered radial arrangement as the Convertible, using one size at the front and a wider size at the rear on 18-inch rims. Choosing tires begins with confirming axle position, then comparing the product options available within the proper front or rear fitment.
The front tire position on the 2021 BMW M240i Coupe uses the smaller of the two metric radial sizes in the staggered setup. That makes front replacement a matter of keeping the correct size and selecting among the available BFGoodrich and Nitto blackwall performance options.
The rear tire position on the 2021 BMW M240i Coupe uses the wider primary fitment, separate from the front size. Keeping that rear sizing intact helps preserve the intended staggered setup, so wheel width and exact rear placement should be confirmed before choosing a replacement.
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 2021 BMW M240i Tires for Sale
Available 2021 BMW M240i tires focus on 18-inch blackwall radial performance fitments. Front-size choices include BFGoodrich g-Force series options and the Nitto NT555 G2, while the rear size is represented by the BFGoodrich g-Force Phenom T/A, with rim-width compatibility varying by size.
Common 2021 BMW M240i tire questions center on the staggered front and rear sizes, 18-inch rim fitment, available performance tire lines, and the checks worth making before installation or road use.
Tire Size & Fitment
What tire size fits a 2021 BMW M240i?
The 2021 BMW M240i uses a staggered tire setup with 225/40R18 at the front and 245/35R18 at the rear. Both sizes are radial fitments on 18-inch wheels, and the same front-and-rear pattern applies to both Coupe and Convertible versions.
That means tire selection starts with identifying axle position, not just the model name. A front tire should not be chosen as though it also covers the rear, and vice versa. It is also worth confirming the actual wheel and tire setup on the car if it has been changed from stock-style sizing at any point.
What size rim does a 2021 BMW M240i use?
The 2021 BMW M240i uses 18-inch rims with both primary tire sizes. The front 225/40R18 and rear 245/35R18 are both built around the same 18-inch wheel diameter, even though the section width and profile differ between the two positions.
Rim diameter is only one part of the fitment picture, so wheel width still matters when choosing a tire. The available 225/40R18 products call for fitment ranges beginning around 7.5 inches wide, while the 245/35R18 product starts at 8 inches. Verifying the actual wheel dimensions helps avoid choosing a tire outside its intended mounting range.
Do all 2021 BMW M240i sub-models use the same tire size?
Coupe and Convertible versions of the 2021 BMW M240i share the same overall tire arrangement, but they do not use one single size at all four corners. Both use 225/40R18 at the front and 245/35R18 at the rear as part of a staggered radial setup.
That distinction matters because a search by sub-model alone can overlook front-versus-rear placement. The safest approach is to confirm whether the tire being replaced is on the front axle or the rear axle, then match the wheel width and exact size accordingly. Cars with aftermarket wheel packages should be checked even more carefully.
Choosing the Right Tire
What should I consider when choosing a 2021 BMW M240i tire?
Start with the correct position-specific size, since the 2021 BMW M240i uses 225/40R18 in front and 245/35R18 in the rear. From there, compare radial construction details such as tire series, brand, rim-width compatibility, load information where stated, and whether you are replacing a front pair, rear pair, or a full staggered set.
The car’s personality makes those details more important than they might be on a non-performance application. Matching the correct size to the correct wheel helps preserve balance and steering feel, while a close look at product line and intended use can help narrow the choice between all-season-style and more performance-focused offerings.
What brands offer tires for the 2021 BMW M240i?
The available 2021 BMW M240i tire options include BFGoodrich and Nitto. In the front 225/40R18 size, BFGoodrich appears across several g-Force series and Nitto appears with the NT555 G2, while the rear 245/35R18 fitment is represented by a BFGoodrich g-Force Phenom T/A.
Brand alone should not make the decision. It is more useful to compare which series is offered in the exact front or rear size you need, along with wheel-width compatibility and the role that tire plays on the car. Buyers replacing only one axle may find product selection differs noticeably between the front and rear fitments.
What tire series are available for the 2021 BMW M240i?
The 2021 BMW M240i fitments include several performance-oriented 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 in the front size more broadly, while the rear size has a narrower product selection.
Comparing series is useful because it helps separate the available options beyond just size and brand. A buyer replacing front tires has more room to compare product character within 225/40R18, while rear replacement in 245/35R18 is more focused. Choosing within the right series should still come after confirming wheel dimensions and axle location.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2021 BMW M240i?
Yes, modifications can change how easily the factory-style 225/40R18 front and 245/35R18 rear sizes work on a 2021 BMW M240i. Aftermarket wheels, changes in wheel width or offset, lowered suspension, alignment changes, or body modifications can all influence clearance and tire selection.
Even when the tire size itself stays the same, a different wheel or suspension setup can alter fender, strut, or steering clearance. That is why it helps to confirm the actual wheel dimensions on the car before choosing a replacement. A staggered performance setup leaves less room for assumptions than a square fitment with one size all around.
What should I inspect before driving a 2021 BMW M240i on new tires?
Before driving a 2021 BMW M240i on new tires, inspect basic installation and condition points first. Confirm that the correct front and rear sizes were mounted, check inflation pressure, and look over each tire for visible damage, bead seating issues, or irregularities that deserve attention before the car is driven in normal use.
A quick follow-up inspection after the first miles is also worthwhile on a performance car with staggered sizing. Recheck pressure, confirm there is no rubbing at full steering lock or under suspension compression, and make sure the wheels were torqued properly. That extra step can catch setup problems early, especially after wheel or suspension changes.
How often should tires on a 2021 BMW M240i be inspected?
Tires on a 2021 BMW M240i should be inspected regularly, not only when tread looks worn. Pressure, tread wear pattern, cuts, punctures, sidewall damage, and uneven wear all deserve attention, especially because the car uses different front and rear sizes that may not wear at the same rate.
A monthly check is a sensible routine for a car in regular use, with another inspection before a longer trip or spirited weekend drive. It also helps to check more closely after impacts with potholes or curbs. Catching a pressure loss or alignment-related wear early can protect both the tire and the handling balance of the staggered setup.
