The 2021 Subaru WRX STI carries forward a long-running all-wheel-drive performance formula that appeals to drivers who want rally-bred attitude in a modern sport sedan. It sits in a later chapter of the STI story, where sharp handling, quick response, and aggressive stance all make tire choice especially important. This exact model uses a 245/35R19 radial tire, so the fitment question is straightforward while the real decision centers on selecting the right tire within that size. Available choices lean toward modern blackwall performance radials from BFGoodrich and Nitto. For a street-driven STI, it pays to balance wheel compatibility, handling expectations, and overall condition before putting miles on a new set.
Which Tire Size Is Right for The 2021 Subaru WRX STI
The 2021 Subaru WRX STI uses one primary tire size: 245/35R19. It is a radial fitment on a 19-inch rim, and that same size carries across the Base and Limited sub-models. That means the main choice is not between multiple factory size groups, but between the available tires in this size, along with their brand, series, and wheel-width compatibility.
A 245/35R19 tire uses a 245-millimeter nominal section width, a 35-series aspect ratio, radial construction, and a 19-inch rim diameter. On the 2021 Subaru WRX STI, this is a modern low-profile performance size that suits the car's aggressive handling character and factory-style wheel diameter. Available choices include blackwall radials from BFGoodrich and Nitto, with series such as g-Force Comp 2 AS, g-Force Phenom T/A, and NT555 G2. The right selection comes down to matching the 19-inch wheel setup, checking rim-width suitability, and choosing the tire character that best fits how the car is actually driven.
Tire fitment is straightforward across the covered 2021 Subaru WRX STI sub-models. Both the Base and Limited use the same primary size, so the focus shifts from trim-level size differences to selecting the right tire within that shared fitment.
1
2021 Subaru WRX STI Base
The 2021 Subaru WRX STI Base uses the same 245/35R19 radial fitment as the rest of the covered lineup. Tire selection is mainly about choosing among the available blackwall performance radials while confirming that the wheel width and overall setup remain consistent with this size.
The 2021 Subaru WRX STI Limited also uses 245/35R19 radial tires on a 19-inch rim. Since the size does not change at the sub-model level, attention should stay on product differences such as brand, tire series, and wheel-width compatibility rather than on alternate primary fitments.
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 Subaru WRX STI Tires for Sale
Available 245/35R19 choices for the 2021 Subaru WRX STI include blackwall radial tires from BFGoodrich and Nitto. The product grid gives buyers a useful comparison across tire series such as g-Force Comp 2 AS, g-Force Phenom T/A, and NT555 G2, along with rim-width specifications where stated.
Owners of a 2021 Subaru WRX STI usually need clear answers on the 245/35R19 fitment, 19-inch rim compatibility, differences between the available radial tires, and the checks that matter before regular driving or a modified-wheel installation.
Tire Size & Fitment
What tire size fits a 2021 Subaru WRX STI?
The 2021 Subaru WRX STI uses a 245/35R19 radial tire. That size applies across the covered WRX STI Base and WRX STI Limited sub-models, so there is one primary fitment to focus on rather than several different size groups.
That makes selection easier, but the size still needs to match the actual wheel setup on the car. If a previous owner changed wheels or altered suspension height, confirm the mounted rim diameter and wheel width before choosing a new tire in 245/35R19.
What size rim does a 2021 Subaru WRX STI use?
The primary tire fitment for the 2021 Subaru WRX STI is built around a 19-inch rim diameter. The 245/35R19 size identifies that wheel diameter directly, and the available tires in this fitment are matched to 19-inch wheels.
Rim diameter is only part of the picture, so it helps to verify wheel width as well before final tire selection. Some available 245/35R19 products include stated rim-width ranges, which becomes especially important if the car has aftermarket wheels instead of its original-style setup.
Do all 2021 Subaru WRX STI sub-models use the same tire size?
Yes. The covered 2021 Subaru WRX STI Base and 2021 Subaru WRX STI Limited both use the same 245/35R19 radial tire size. There is no separate primary size split between those two sub-models.
That consistency means trim level is less important than the actual condition and configuration of the car in front of you. A modified STI can still require extra checking for wheel width, tire-to-fender clearance, and overall fitment even when the original sub-model fitment is the same.
Choosing the Right Tire
What should I consider when choosing a 245/35R19 tire for a 2021 Subaru WRX STI?
Start with the correct 245/35R19 size and confirm that the tire matches the car's 19-inch wheel setup. From there, compare construction, brand, tire series, and any stated rim-width specifications, since the available choices for this STI are all radial but not identical in their product details.
A useful next step is deciding how the car is used most often. A regularly driven street STI, a fair-weather weekend car, and a modified car on non-stock wheels may all lead you to different priorities, so wheel compatibility and intended use should guide the final choice.
What sidewall styles are available for 2021 Subaru WRX STI tires?
The available 245/35R19 tires for the 2021 Subaru WRX STI use a blackwall sidewall style. That keeps the look clean and contemporary, which suits the later-model STI's aggressive performance appearance without introducing vintage-style sidewall treatments.
Since sidewall appearance does not vary here, the better comparison points are brand, tire series, and fitment specifications such as wheel-width range where stated. That helps narrow the choice based on how the car is equipped rather than expecting a wide appearance split within this size.
What brands offer tires for the 2021 Subaru WRX STI?
BFGoodrich and Nitto both offer 245/35R19 radial tires for the 2021 Subaru WRX STI. Within that size, BFGoodrich appears in more than one tire series, while Nitto is also represented with a modern performance-oriented option.
Brand alone should not be the only deciding factor. Compare the exact tire series, confirm the wheel-width range when it is stated, and think about whether the car is kept close to stock or has wheel and suspension changes that make fitment details more important.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2021 Subaru WRX STI?
Yes. Even though the primary fitment is 245/35R19, modifications can change whether that size works the same way on a particular 2021 Subaru WRX STI. Aftermarket wheels, altered offset, suspension changes, or lowering can all affect clearance and how the tire sits within the fender opening.
A modified car should be checked at the wheel itself, not just by model year and trim. Measure the rim diameter and width, look at inner and outer clearance, and turn the steering through its range before assuming any replacement tire in this size will behave the same way.
What should I inspect before driving a 2021 Subaru WRX STI on new tires?
Check that the installed tires are the correct 245/35R19 size and that they are mounted on compatible 19-inch wheels. It also helps to inspect inflation pressure, bead seating, valve stems, lug torque, and basic clearance at the strut, fender, and inner wheelhouse.
A short test drive should follow with attention to vibration, rubbing, or steering pull. Any STI that has been modified, stored for long periods, or recently had suspension work deserves an extra look afterward to make sure the tires are wearing evenly and holding pressure properly.
How often should tires on a 2021 Subaru WRX STI be inspected?
Tires on a 2021 Subaru WRX STI should be inspected regularly, not just when tread appears low. A quick visual check before routine driving and a more careful inspection at service intervals helps catch uneven wear, punctures, sidewall damage, or pressure loss early.
Performance-oriented cars can show alignment and wear issues quickly, especially on low-profile tires like 245/35R19. Looking over the tread shoulders, checking pressures when cold, and paying attention after pothole impacts or seasonal storage all help protect both fitment and road manners.
