pixel_player74968299 Welcome to the forum 🙂
The wheels to upgrade the PF Bratislava are from last event, so you can no longer get them. For players like yourself, who were unable to fully upgrade the Bratislava, PF very nicely gave you the option to upgrade the ship with gems. This means that if you do not have enough wheels, and wish to fully upgrade the ship, using gems is the only way to do so.
Please make a habit of reading the in-game messages, as all of this information was available there ✉
