The 2018 BMW i3s took BMW’s already distinctive carbon-fiber city EV and gave it a sharper, more planted stance that appealed to drivers who wanted the i3’s efficiency with a sportier look and feel. Its narrow, tall 20-inch tire package is a defining part of that formula, helping the car balance low rolling resistance, quick response, and compact packaging. Front fitment uses 175/55R20 radial tires, while the rear uses 195/50R20 radial tires. That staggered arrangement makes tire selection less about broad experimentation and more about getting the correct front-to-rear setup. Before replacing anything, confirm position on the car and keep wheel size and overall proportions in mind.
Which Tire Size Is Right for The 2018 BMW i3s
The 2018 BMW i3s uses two primary tire sizes, and the first step is confirming whether you are replacing a front or rear tire. Both sizes are radial tires built for a 20-inch rim, but they are not interchangeable because this BMW uses a staggered setup with one size on the front axle and another on the rear.
The 175/55R20 size uses a modern metric format: 175 is the nominal section width in millimeters, 55 is the aspect ratio, R identifies radial construction, and 20 is the rim diameter in inches. On the 2018 BMW i3s, this size is used on the front axle, where its narrow footprint is part of the car’s intended tire layout. Because the i3s is not a square tire setup, this size should be chosen specifically for front-position replacement. Matching the correct axle position is just as important as matching the size itself.
The 195/50R20 size is also a modern metric radial, with 195 indicating nominal section width in millimeters, 50 indicating aspect ratio, and 20 indicating the wheel diameter in inches. On the 2018 BMW i3s, this is the rear tire size, giving the car a wider rear fitment than the front. That wider rear specification is a key part of the vehicle’s staggered arrangement and should not be confused with the front tire size. Rear-tire replacement should start with confirming that the wheel and tire position remain original.
Fitment is consistent across the covered i3s versions in the sense that both use the same staggered tire layout. Checking the exact sub-model still matters so the correct front and rear sizes stay matched to the vehicle’s existing wheel setup.
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2018 BMW i3s Base Front
The 2018 BMW i3s Base Front uses the narrower front tire size in the vehicle’s staggered radial setup. Tire selection here should focus on replacing the front position with the proper 20-inch fitment rather than trying to match the wider rear tire.
The 2018 BMW i3s Base Rear uses the wider rear tire size that completes the car’s front-to-rear stagger. Choosing a rear replacement means confirming that the wheel remains the original 20-inch rear application and not assuming the front size carries over.
The 2018 BMW i3s Range Extender Front uses the same front radial tire size as the standard i3s front position. That keeps front fitment straightforward, but the tire still needs to be selected as a front application within the staggered overall setup.
The 2018 BMW i3s Range Extender Rear uses the same rear radial tire size as the standard i3s rear position. Rear replacement should be handled as a position-specific fitment, with attention to the existing rear wheel and the car’s staggered sizing layout.
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.
Frequently Asked Questions
BMW i3s tire questions usually center on the staggered front and rear sizing, 20-inch rim fitment, and how to keep replacement tires matched to the car’s original layout. The answers below focus on those exact issues for the 2018 BMW i3s.
Tire Size & Fitment
What tire size fits a 2018 BMW i3s?
The 2018 BMW i3s uses a staggered tire setup with 175/55R20 on the front and 195/50R20 on the rear. Both are radial tire sizes for 20-inch wheels, so the correct choice depends on where the tire is mounted rather than on model year alone.
That means replacement starts by identifying front versus rear position before choosing a tire. A staggered setup is common on sporty applications, and it matters because the two sizes have different widths and should be matched to the correct wheel and axle location.
What size rim does a 2018 BMW i3s use?
The 2018 BMW i3s uses 20-inch rims with both of its primary tire sizes. The front 175/55R20 and rear 195/50R20 are both built around that same 20-inch rim diameter, even though the tires themselves differ in width and profile.
Rim diameter is only one part of fitment, so it is still worth checking wheel width and the actual wheel position on the car before replacement. A 20-inch wheel does not make the front and rear tires interchangeable, especially on a staggered BMW setup like the i3s.
Do all 2018 BMW i3s sub-models use the same tire size?
The covered 2018 BMW i3s sub-models share the same overall staggered tire arrangement rather than one single size at all four corners. Base and Range Extender versions use 175/55R20 on the front and 195/50R20 on the rear.
That makes sub-model fitment relatively straightforward, but front and rear positions still need to be confirmed before ordering or mounting tires. The important distinction is not Base versus Range Extender as much as making sure the front axle keeps the front size and the rear axle keeps the rear size.
Choosing the Right Tire
What should I consider when choosing a 175/55R20 or 195/50R20 tire for a 2018 BMW i3s?
Start with the correct axle position, because the 2018 BMW i3s does not use the same tire size front and rear. The front takes 175/55R20 and the rear takes 195/50R20, both in radial construction on 20-inch rims.
After size and position are confirmed, look closely at wheel compatibility and whether the car still has its original wheel setup. Any change in wheel width, offset, suspension height, or body clearance can affect replacement choices, so those details matter before moving away from the intended staggered layout.
How do I choose between the available 20-inch tires for a 2018 BMW i3s?
The main choice is not between two interchangeable 20-inch tires, but between the correct front and rear sizes used on the car. A 2018 BMW i3s needs 175/55R20 at the front and 195/50R20 at the rear, so position-specific replacement comes first.
Once the proper size is identified, compare tires in terms of how closely they suit the car’s existing wheel setup and intended use. Drivers who want to preserve the original feel of the i3s should avoid treating any 20-inch tire as universal and instead keep the staggered arrangement intact.
What rim-fitment details should I compare when choosing 2018 BMW i3s tires?
The first rim-fitment detail is diameter, and the 2018 BMW i3s uses 20-inch wheels for both front and rear tires. After that, the important comparison is whether the wheel is the correct front or rear application for the size being replaced.
Wheel width and any changes in offset should also be checked, especially if the car has aftermarket wheels. Even with the correct 20-inch diameter, a front tire and a rear tire are designed for different positions on the i3s, so the full wheel setup needs to stay consistent.
Restoration & Appearance
Does correct tire fitment matter for a 2018 BMW i3s restoration or preservation project?
Yes, correct tire fitment matters because the 2018 BMW i3s uses a distinctive staggered 20-inch setup that contributes to both its appearance and its intended stance. Keeping 175/55R20 on the front and 195/50R20 on the rear preserves the proportions associated with the model.
For a preservation-minded owner, the goal is usually to maintain the original front-to-rear relationship rather than simply finding any tire that mounts on a 20-inch wheel. If exact presentation matters, compare the current wheel and tire combination carefully and avoid mixing sizes across the two axle positions.
How does tire sizing affect the appearance of a 2018 BMW i3s?
Tire sizing plays a visible role on the 2018 BMW i3s because the car uses narrow-profile 20-inch tires and a wider rear size than front. That staggered layout is part of the i3s look, giving the car a different visual balance than a square four-tire setup would.
Changing away from the intended front and rear relationship can alter how the car sits and how the wheels fill the arches. Owners who care about maintaining the i3s character should match the proper tire size to each axle and confirm that the wheel package has not been changed over time.
Fitment, Maintenance & Road Use
Can modifications affect tire fitment on a 2018 BMW i3s?
Yes, modifications can affect tire fitment on a 2018 BMW i3s, especially because the car already uses a staggered front and rear arrangement. Changes to wheel width, offset, suspension height, or body clearance can all influence how a 175/55R20 front or 195/50R20 rear tire fits the car.
A modified i3s should be checked carefully before replacement tires are selected or mounted. Even small setup changes can affect steering clearance, inner-wheel clearance, or fender room, so confirming the actual wheel and suspension configuration helps prevent choosing the right size for the wrong setup.
What should I inspect before driving a 2018 BMW i3s on new tires?
Before driving a 2018 BMW i3s on new tires, confirm that the front and rear sizes are installed in the correct positions and that all four tires are properly inflated. It is also wise to inspect wheels for damage and make sure lug hardware and mounting surfaces are in good condition.
A short road test should include attention to clearance, steering feel, and any vibration that suggests a mounting or balance issue. On a car with a staggered layout, it is especially important to verify that the narrower front tires and wider rear tires were not accidentally swapped during installation.
How often should tires on a 2018 BMW i3s be inspected?
Tires on a 2018 BMW i3s should be inspected regularly, not just when tread looks low. Routine checks should include air pressure, tread wear pattern, cuts, bulges, punctures, and sidewall condition, with special attention to keeping front and rear tire positions properly identified.
An inspection before longer drives is especially useful, and low-mileage vehicles should not be ignored simply because they are driven less often. Tires can age as well as wear, so a stored or lightly used i3s still benefits from periodic checks for cracking, air loss, and uneven wear across the staggered setup.
