Yes, the hub is identical
Same 5x108 PCD and same 63.4 mm centre bore: wheels from Smart #3 bolt on and centre on Volvo EX40 axe arrière without rings. You still need to check the offset and tyres, detailed below.
≈: width estimated from the original tyre size.
Wheel by wheel: offset and tyres
Each original wheel from Smart #3 is compared with the one from Volvo EX40 axe arrière of the same diameter: how much closer the wheel gets to the shock absorber or how far it sticks out of the wheel arch, and whether the tyre keeps the same overall diameter.
- ✓
≈7.5Jx19 ET48 · 235/45R19 — Fits like the original
Compared with the original 8.5Jx19 ET56 on Volvo EX40 axe arrière: shock absorber side −20.7 mm, wheel arch side −4.7 mm, tyre diameter −2.5 % : fit it with the original tyre size of Volvo EX40 axe arrière (255/45R19), not that of Smart #3.
Comparison for guidance only (estimated width). Check in detail
Before fitting the wheels
An identical hub is not enough: offset, width and diameter change the position of the wheel, and larger calipers can touch a smaller wheel. Original wheels often use bolts or nuts with a specific seat: keep the fixings intended for the wheel, with the thread of Volvo EX40 axe arrière (M14x1.50), tightened to the torque shown on its vehicle page. Finally, check that the size is among the approved fitments for your vehicle. This comparison is for guidance only: have the fitting approved by a professional.
And the other way round: wheels from Volvo EX40 axe arrière on Smart #3?