Would you like setup tips for legal emulation or recommendations for official Sonic racing games on PC instead?
Sonic Riders: Zero Gravity was originally released in 2008 for the PlayStation 2 and Nintendo Wii. Sega never released an official PC version of this game. Any website offering a "Sonic Riders: Zero Gravity PC download" is distributing an unofficial port, typically via emulation (PS2 or Wii emulators like PCSX2 or Dolphin) bundled with the game's ROM or ISO.
I understand you're looking for information regarding a PC download of Sonic Riders: Zero Gravity . However, I must provide an important clarification before proceeding.