The 2018 Kia Optima sits in the midsize sedan class with a strong emphasis on everyday comfort, modern styling, and trim-dependent personality that ranges from efficient hybrid models to sharper sport-oriented versions. That variation matters when it is time to choose tires, because the 2018 Kia Optima uses three different primary radial sizes: 205/65R16, 215/55R17, and 235/45R18. The available choices here lean toward modern performance-minded radial offerings in blackwall form, with different g-Force series depending on size. The right pick starts with confirming the exact trim and wheel diameter, then balancing ride, appearance, and intended road use.
Which Tire Size Is Right for The 2018 Kia Optima
The 2018 Kia Optima uses three primary tire sizes, and the correct one depends on the exact sub-model and wheel diameter. All three are radial fitments, but they span 16-inch, 17-inch, and 18-inch rims, so the first step is confirming which wheels are actually on the car. Once that is settled, the decision becomes choosing the right tire series and specifications within the proper size.
In 215/55R17, the 215 identifies section width in millimeters, the 55 is the aspect ratio, the R indicates radial construction, and the 17 is the wheel diameter in inches. This size suits 2018 Kia Optima configurations that use a 17-inch radial setup and keeps the selection focused on modern passenger-car tire behavior. Available choices in this size come from BFGoodrich in blackwall form, including the g-Force Comp 2 AS and g-Force Phenom T/A series. It is a useful size to evaluate when the car already wears 17-inch wheels and the goal is to stay within the intended fitment range.
In 205/65R16, the 205 is the nominal section width in millimeters, the 65 is the aspect ratio, the R marks radial construction, and the 16 is the rim diameter in inches. On the 2018 Kia Optima, this size belongs to trims that use a 16-inch wheel and reflects a straightforward modern radial fitment. Its dimensions point to a practical, trim-specific application rather than a one-size-fits-all replacement across the lineup. Choosing this size starts with confirming that the car has the correct 16-inch wheels and has not been changed to a different factory or aftermarket setup.
In 235/45R18, the 235 represents section width in millimeters, the 45 is the aspect ratio, the R denotes radial construction, and the 18 is the wheel diameter in inches. This size serves the 2018 Kia Optima trims that use an 18-inch wheel and carries a noticeably sportier sizing profile than the smaller Optima fitments. BFGoodrich offers several blackwall choices here, including the g-Force Comp 2 AS, g-Force Sport Comp 2, and g-Force Phenom T/A series. It is the right size to examine when the car is equipped with 18-inch wheels and tire selection centers on series differences within that larger fitment.
Tire fitment for the 2018 Kia Optima varies by sub-model, and some trims are tied to different wheel diameters. Checking the exact trim matters before choosing a tire, especially because the lineup spans 16-inch, 17-inch, and 18-inch applications.
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2018 Kia Optima EX
The 2018 Kia Optima EX uses a 17-inch radial tire fitment centered on 215/55R17. Tire selection here is less about size confusion and more about comparing available blackwall radial choices within the correct 17-inch specification.
The 2018 Kia Optima Hybrid EX also uses the 215/55R17 radial size on a 17-inch wheel. That keeps fitment straightforward, with the main decision focused on choosing the tire series that best matches how the car is driven.
The 2018 Kia Optima Hybrid Premium uses the 205/65R16 radial size. Tire selection begins with confirming the 16-inch wheel setup, especially on a car that may have seen wheel changes after delivery.
The 2018 Kia Optima LX uses the 205/65R16 radial fitment. For this trim, the key is staying with the proper 16-inch size and checking the current wheel setup before moving to any different diameter or profile.
The 2018 Kia Optima LX 1.6T uses the same 205/65R16 radial tire size as other 16-inch-equipped versions. That makes the fitment simple, but it still helps to confirm the actual wheel diameter if the car has been modified.
The 2018 Kia Optima Plug-In Hybrid EX uses a 17-inch radial fitment with 215/55R17. Choosing a tire for this trim means comparing the available 17-inch options rather than sorting through multiple primary sizes.
The 2018 Kia Optima S can use either a 17-inch or 18-inch radial tire size, so wheel diameter must be confirmed before anything else. Once that is established, tire selection becomes a matter of choosing within the correct size and matching the car's actual setup.
The 2018 Kia Optima SX uses the 235/45R18 radial size on an 18-inch wheel. This trim's tire choice starts with the larger wheel package and then narrows to the available blackwall g-Force series options.
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 Kia Optima Tires for Sale
Available 2018 Kia Optima tire choices center on BFGoodrich radial blackwall options in the 215/55R17 and 235/45R18 sizes. The product grid is most useful for comparing g-Force series differences, rim-width compatibility, weight, and selected load specifications within the correct fitment.
These FAQs focus on 2018 Kia Optima tire size by trim, wheel-diameter differences, available radial choices, product selection factors, and the fitment checks that matter before regular driving or after wheel changes.
Tire Size & Fitment
What tire size fits a 2018 Kia Optima?
A 2018 Kia Optima can use 205/65R16, 215/55R17, or 235/45R18, depending on the sub-model and wheel package. All three are radial sizes, but they are tied to different rim diameters, so there is not one universal tire size for every Optima in the lineup.
The most important step is identifying the exact trim and confirming the actual wheel diameter on the car. An Optima S deserves extra attention because it can use either 215/55R17 or 235/45R18, and any past wheel change means the current setup should be checked before ordering replacement tires.
What size rim does a 2018 Kia Optima use?
The 2018 Kia Optima uses 16-inch, 17-inch, or 18-inch rims, depending on the sub-model. The 205/65R16 size belongs to a 16-inch rim, 215/55R17 belongs to a 17-inch rim, and 235/45R18 belongs to an 18-inch rim.
Rim diameter should be confirmed before choosing a tire because each Optima size is built around a different wheel. Checking the sidewall marking on the current tire and verifying the wheel itself helps avoid mixing up trim-level fitments, especially on cars that may have received factory-option or aftermarket wheel changes.
Why does the 2018 Kia Optima have more than one tire size?
The 2018 Kia Optima has more than one tire size because different sub-models use different wheel packages. Some trims use 16-inch wheels with 205/65R16 tires, others use 17-inch wheels with 215/55R17 tires, and higher-spec applications move to 18-inch wheels with 235/45R18 tires.
That means tire selection starts with trim and wheel confirmation rather than brand preference alone. A buyer looking at replacement tires should match the car's actual wheel diameter first, then compare the available options within that one correct size so the fitment stays aligned with the vehicle's current setup.
Choosing the Right Tire
What should I consider when choosing a 2018 Kia Optima tire?
Start with the correct tire size for the exact 2018 Kia Optima sub-model, because the lineup uses 205/65R16, 215/55R17, or 235/45R18. After size, compare the tire series, construction details, rim-width specification, weight, and any stated load information that applies to the specific product.
The right choice depends on the wheel package already on the car and how the car is used day to day. A 17-inch EX and an 18-inch SX are not shopping the same fitment, so choosing within the proper size first helps narrow the decision to the product characteristics that actually matter.
What brands offer tires for the 2018 Kia Optima?
The available 2018 Kia Optima products here are from BFGoodrich. In the supported 17-inch and 18-inch sizes, the choices include several g-Force series offerings, giving buyers multiple radial options within the correct fitment instead of forcing a single product path.
That makes the comparison less about switching brands and more about selecting the right BFGoodrich series for the wheel size on the car. It is still worth reviewing rim-width compatibility, weight, and any stated load specification so the final choice matches both the tire size and the Optima's actual setup.
What tire series are available for the 2018 Kia Optima?
The 2018 Kia Optima products shown here include BFGoodrich g-Force Comp 2 AS, g-Force Phenom T/A, and, in 235/45R18, g-Force Sport Comp 2. Those series appear in the 215/55R17 and 235/45R18 fitments and give buyers more than one radial option within the same basic size.
Series choice matters once the correct tire size is settled, because it helps separate one product from another without changing the fitment itself. Comparing the available series alongside rim-width range, weight, and sidewall style keeps the decision focused on a tire that suits the wheel package already on the car.
Restoration & Appearance
Does correct tire fitment matter for a 2018 Kia Optima restoration?
Yes, correct tire fitment still matters on a 2018 Kia Optima restoration or refurbishment, even though it is a newer vehicle than most collector-era cars. The proper size is tied to the sub-model and wheel diameter, so keeping the car in 205/65R16, 215/55R17, or 235/45R18 as appropriate preserves the intended proportions and basic stance.
Appearance can change quickly when a later-model sedan ends up on the wrong diameter or profile tire. Anyone returning the car to stock-style presentation should confirm the exact trim, verify the current wheels, and compare the replacement tire's visual character so the finished look stays consistent with the vehicle's original configuration.
How does tire construction affect the appearance of a restored 2018 Kia Optima?
On a 2018 Kia Optima, tire construction is straightforward because the primary fitments are radial. That means the appearance discussion is less about bias-ply versus radial and more about staying with the correct modern radial size and choosing a tire whose proportions suit the factory-style wheel diameter.
Sidewall treatment also influences the final look, and the available options here are blackwall tires. For an owner refreshing the car cosmetically, matching the proper size to the correct 16-inch, 17-inch, or 18-inch wheel package usually has a bigger effect on appearance than changing between product series within the same fitment.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2018 Kia Optima?
Yes, modifications can affect tire fitment on a 2018 Kia Optima. Wheel swaps, changes in wheel width, suspension lowering, and other alterations can change the space available for a 205/65R16, 215/55R17, or 235/45R18 tire, even when the size seems close to what the car originally used.
A modified Optima should be checked for wheel diameter, wheel width, and clearance at full steering lock and suspension movement before replacement tires are chosen. That matters most on trims with larger wheels or cars that have moved away from their original setup, because fitment depends on the car as it sits today.
What should I inspect before driving a 2018 Kia Optima on new tires?
Before driving a 2018 Kia Optima on new tires, confirm that the tire size matches the wheel diameter and that inflation is set correctly for the vehicle's needs. It also helps to inspect the wheels for damage and make sure the tires seat properly without rubbing or visible clearance issues.
A short initial drive should be followed by another visual check for air loss, unusual contact marks, or any sign that the tire is too close to suspension or body components. On a car with previous wheel or suspension changes, that follow-up inspection is especially worthwhile before regular commuting or longer highway use.
How often should tires on a 2018 Kia Optima be inspected?
Tires on a 2018 Kia Optima should be inspected regularly, not just when replacement time arrives. A routine look at tread wear, sidewall condition, cuts, bulges, and air pressure helps catch problems early, especially on a daily-driven sedan that may see changing weather and road conditions.
More frequent checks are smart before longer trips or after impacts with potholes and curbs. Uneven wear can also point to alignment or suspension issues, so consistent inspection is useful for more than tire life alone. Keeping an eye on condition and pressure helps any of the Optima's three fitments deliver more predictable road behavior.
