The smart #5 leaves the factory on 245/50 R19 and 255/40 R21 and 255/45 R20 depending on wheel size, and the 245/50 R19 105V XL below is the one most owners are replacing. XL is not optional here; it is what the car was type approved on. The BMW i7 takes the same size.
| Generation | Trim | Wheel | Tyre size | Load index | Speed | Construction | Marking | Pressure |
|---|---|---|---|---|---|---|---|---|
| Current | 19in wheels | 19in | 245/50 R19 | 105 | V | XL | none | see plate |
| Current | 20in wheels | 20in | 255/45 R20 | 105 | V | XL | none | see plate |
| Current | 21in wheels | 21in | 255/40 R21 | 102 | V | XL | none | see plate |
Your own placard is the authority. You will find it on the on the driver's door jamb, on the B-pillar. Where it disagrees with this page, it wins. Match or exceed the size, load index, speed rating and construction class it gives, and use its pressure figure rather than anything printed on the tyre.
The #5 is the largest smart, and its 19 and 20 inch tyres share a load index of 105, 925 kg each, even though the 20 inch is 10 mm wider. The 21 inch 255/40 R21 drops to 102, or 850 kg.
All three sizes are XL and V rated, and Michelin lists all three against every version from the 250 kW car to the 475 kW Brabus. The 19 inch 245/50 R19 has the deepest sidewall, at about 123 mm.
How these were chosen. Everything here already clears this vehicle's own load index, speed rating and construction class. Each heading is a question about use rather than a ranking. The whole method.
Graded A for wet grip, and nothing else that fits is graded higher. Graded A for rolling resistance, the best of anything here, and that is the figure that shows on the range display. EPREL registration 2626877.
Graded A for rolling resistance, the best of anything here, and that is the figure that shows on the range display. Graded A for wet grip, and nothing else that fits is graded higher. EPREL registration 1367619.
Measured at 70 decibels, the quietest of the set. Graded A for wet grip, and nothing else that fits is graded higher. EPREL registration 2644146.
A winter tyre, so a second set rather than a replacement for what is on the car now. Graded D for wet grip. Graded B for rolling resistance. EPREL registration 727673.
Rated below the speed this vehicle left the factory at, which is permitted for a winter tyre and is why it carries a T or an R. The load index and the construction class still match. Do not exceed the tyre's own rating while it is fitted.
Ordering is by the registered label figure, not by anything we think of them.
Designed for electric cars from the ground up rather than adapted from a combustion tyre, and the winner of the 2025 Auto Bild EV tyre test.
An all-season tyre for electric cars, which is a sensible default in a climate that rarely makes a full winter tyre worth the second set of wheels.
Graded A for fuel efficiency in several of the sizes heavy electric cars use, which is a harder result on a two tonne car than it looks.
A studless winter tyre built for the weight and the rolling resistance demands of an electric car.
Rated below the speed this vehicle left the factory at, which is permitted for a winter tyre and is why it carries a T or an R. The load index and the construction class still match. Do not exceed the tyre's own rating while it is fitted.
Sumitomo's electric-car range at a price well below the flagships, with the load ratings heavy battery cars actually need.
A Korean-built summer tyre that turns up as original equipment more often than its profile suggests, graded A for fuel efficiency.
A high performance summer tyre available in the Y rated sizes that heavy, fast electric cars are specified with.
Graded A for wet grip in the large sizes electric SUVs run, which is the grade worth paying for.
A performance summer tyre built for heavy, fast electric cars, with an acoustic foam liner bonded inside the cavity.
Every figure here comes from one tyre maker's own fitment data, checked across different years or trims. That is a second look rather than a second opinion, so check the label on your door jamb before you buy.
.jpg){kind=link}