Yes, the hub is identical
Same 5x110 PCD and same 65.1 mm centre bore: wheels from Saturn Sky bolt on and centre on Opel GT Convertible 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 Saturn Sky is compared with the one from Opel GT Convertible 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.
- ✓
≈7.5Jx18 ET45 · 245/45R18 — Fits like the original
Compared with the original 8Jx18 ET55 on Opel GT Convertible: shock absorber side −16.4 mm, wheel arch side +3.7 mm, tyre diameter +0 %.
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 Opel GT Convertible (Ecrous - 12x1.50), 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 Opel GT Convertible on Saturn Sky?