Gear Part

Gear Parts (ギアパツ) are special and technical mods (modifications) of Extreme Gear debuting in Sonic Riders: Zero Gravity and later carried on into Sonic Free Riders which plays an important role in the gameplay of these two racing games. The Gear Parts of a Gear are 'programmed' into the Gear which when activated, provides/upgrades various characteristics to/of the Gear while in a race which ranges from upgrading the basic attributes of the Gear (Dash/Acceleration, Limit/Top Speed, Power/Durability or Cornering/Turn) to additional abilities such as the ability to grind on rails.

Sonic Riders: Zero Gravity
As this game debuted the content of Gear Parts, most of the Extreme Gear obtained in Sonic Riders: Zero Gravity have a maximum of 3 Gear Parts installed into the Gear. While in a race, the Gear Parts will remain inactive until the character acquires and trades a specific number of Rings for activating each of those Gear Part. The Gear is covered by an orange-colored void indicating that the Gear is modified with that Gear Part in effect.

By the player's will, he/she does not need to activate all of the Gear Parts in order so for example, if the character has enough Rings for activating a 'Max Speed UP' Gear Part but wants to save Rings for the 'Air-Ride' Gear Part which obviously costs more Rings, he/she may save the number of Rings for that 'Air-Ride' Gear Part instead of spending the Rings for the current Gear Part. Note that some Gear Parts of a Gear may require a high number of Rings and some Gear Parts of a Gear must have a previous Gear Part activated beforehand.

Sonic Free Riders
The concept of Gear Parts return in Sonic Free Riders, exclusively for the Xbox 360 Kinect, but with different gameplay mechanisms. Unlike in Sonic Riders: Zero Gravity, the Gear Parts are seperate from the Extreme Gears, and the player can equip any Gear Part to any Extreme Gear, as opposed to having specific Gears pre-installed in the Extreme Gear, allowing a larger range of abilities that an Extreme Gear can possess during a race. The player is required to spend Rings in the shop to acquire more Gear Parts in addition with purchasing Extreme Gear.

Most Board type Extreme Gear can be equipped up to two Gear Parts of any type while most Bike type Extreme Gear can only be equipped with one Gear Part. Some Bike type  Extreme Gear, however, cannot be equipped with the "Power Skill", since all Bikes come with the default ability of the Power skill.

While racing on a Board Gear, only one Gear Part is active at a time. The player's stance when playing the game is what determines which Gear Part is currently in effect. By switching the player's current stance (by facing in the opposite direction), the player can activate the other Gear Part equipped to the Extreme Gear, while deactivating the first Gear Part.