Extreme Gear

"Still, how can a plank like that just float?"

"That's easy to explain. According to the Kutta–Joukowski Theorem, the control surface flow is balanced by the inverse kinetics of the--"

"STOP!! I get it, okay!? It just floats and that's good enough for me!"

- Knuckles and Tails discussing Extreme Gear.

Extreme Gear (エクストリーム・ギア), sometimes referred to as Gear, is the main source of transportation and racing in Sonic Riders and its sequels, Sonic Riders: Zero Gravity and Sonic Free Riders. Extreme Gear comes with in-game characters and can also be purchased with Rings earned in races and achieving certain requirements.

Powers and Abilities
Extreme Gears are capable of allowing their rider to fly, or at least hover, at high speeds. In Sonic Riders, Extreme Gear required the use of Air as fuel, but this concept was dropped in Sonic Riders: Zero Gravity for the use of Gravity Points, though it was brought back for Sonic Free Riders and the Gravity Points was dropped. This fuel is also used for using speed boosts to accelerate the rider to high speeds (known as "Air Boosts" or "Kick Dashes". Extreme Gear is also the way of transportation for the Babylon Rogues, as well as Sonic, Tails, Knuckles and Amy during the Sonic Riders games.

Extreme Gear each come with a variety of unique abilities such as the ability to grind on rails, glide through the air (known as Air Ride), smash barricades and obstacles in the rider's path or improve their own attributes (Limit/Top Speed, Dash/Acceleration, Curve/Handling and Power/Durability) etc. In Sonic Riders: Zero Gravity and Sonic Free Riders, Extreme Gear comes with components of such abilities called Gear Parts although in all Sonic Riders games, some Extreme Gear have their own abilities such as the Gambler, which can manipulate the number of Rings the player earns in a race based on the position he/she comes in.

Types of Extreme Gear
Extreme Gear comes in several different varieties, each with different ratings in the four attributes (Limit/Top Speed, Dash/Acceleration, Curve/Handling and Power/Durability) and some Extreme Gear comes with their own special abilities. Every character has a "starting Gear" with statistics specially designed for that rider, and in most cases only that rider can use that Gear. In Sonic Riders: Zero Gravity, some Gear Parts can physically transform the Extreme Gear into another type.

Besides statistics and abilities, Extreme Gears also comes in many different shapes and sizes and many unorthodox Gear are present in the first two Sonic Riders games. In fact, the first Extreme Gear ever made is actually a carpet, similar to one a genie would use. Other unconventional Gears include a flying broomstick, a cloud and even the Opa-Opa spaceship. Despite their variating appearances though, all existing Extreme Gear fall into one of the six following classes listed below:

Board
Board-type Gears are the most common Extreme Gear and the first available to the player in all three games. In fact, they are so common that almost every character's "starting Gear" is a board. In Sonic Riders, boards are the most balanced class of Gear, having average statistics and an average rate of Air-consumption and is used in Story Mode by every character except Dr. Eggman. In Sonic Riders: Zero Gravity, Board-type Extreme Gears are again a balanced, middle class, with average statistics and some Boards allow the rider to grind in Grind Areas (an ability previously restricted to characters in Sonic Riders, not their Gear). In Sonic Free Riders, most Board type Gears can be equipped with two Gear Parts.

Skate
Skate type Extreme Gears are a less powerful class of Extreme Gear, but are more agile and in Sonic Riders, more Air-efficient. In Sonic Riders: Zero Gravity, Skate type Extreme Gears allow their rider to grind on Grind Areas (an ability previously in Sonic Riders is restricted to characters, not their Gear).

Bike
Bike type Extreme Gears are a more powerful but less maneuverable class of Extreme Gear and they resemble sport motorbikes. In Sonic Riders, Bike type Gears are less fuel efficient while in Sonic Riders: Zero Gravity and Sonic Free Riders, bikes allow the rider to punch through obstacles and barricades without slowing down, gaining Air/Gravity Points for each obstacle destroyed (an ability previously restricted to characters, not their Gear, in Sonic Riders). In Sonic Free Riders, Bike type Gears can only be equipped with one Gear Part.

Air Ride
Air Ride type Extreme Gears have only appeared in Sonic Riders: Zero Gravity. Air Ride type Gears are similar in shape to the Greek letter Psi (Ψ), and it is ridden by kneeling or lying down on the Gear. Air Ride type Gears are capable of Air Riding (an ability previously restricted to characters, not their Gear, in Sonic Riders). It should be noted though, that even though SCR-HD resembles a Wheel type Extreme Gear, it only has Air Ride type Gear capabilities.

Yacht
Yacht type Extreme Gears have only appeared in Sonic Riders: Zero Gravity. Despite the name, Yacht type Gears are more reminiscent of windsurf boards than boats. In addition to Air Ride type Gear capabilities, Yacht type Gear allows the rider to ride on slipstreams and accelerate on them while riding directly behind an opponent, which is otherwise known as "drafting". Without this trait, Yacht type Gears tend to have very poor top speed compared to other Gear types.

Wheel
Wheel type Extreme Gears have only appeared in Sonic Riders: Zero Gravity. They appear to be based on monowheels. Wheel type Gears are the largest Extreme Gear, as they need to be tall enough for the rider to sit inside and pilot. In addition to Bike capabilities (being able to crash through obstacles and barricades without slowing down, gaining GP for each obstacle smashed), Wheel type Gears have the ability to use Slide Turns that can traverse through sharp turns, similar to the Air Slide in Sonic Riders. The drawback of Wheel type Gear is that they cannot perform Gravity Control to the full extent of most of the other Gear types, meaning that they will have to rely on Slide Turns to traverse through sharp corners and cannot access shortcuts that normally require the use of Gravity Control. It should be noted though, that even SCR-HD resembles a Wheel type Gear, it only has Air Ride type Gear capabilities.

Extreme Gear Producers
While the creation of most of the Extreme Gear available to buy don't have much explanation on who made them, there are the few business corporations that were mentioned for the characters' own Extreme Gears as well as a few other Gears. Some of the Gears were redesigned by either Tails or Wave to fit their friends' skills.

Robotnik Corp.
Dr. Eggman's corporation that produces Extreme Gear. First appearing in Sonic Riders and responsible for the character boards, even Sonic, Tails and Knuckles' boards. However, Eggman may have provided, or at least sold the boards which Tails then modified to suit his friends' needs.

Babylon Standard
While the Babylon Rogues may be a band of thieves, they seem to have run their own business in production of Extreme Gear. However, since the only Gears made by Babylon Standards are the Type Gears, these Gears are solely for themselves. In Sonic Riders: Zero Gravity it was never mentioned, just that Wave redesigned Type-J, S and W. It's more likely that it is a type of basic model used exclusivly by Babylonians.

Accevive Corp.
Introduced in Sonic Riders: Zero Gravity, this corporation is responsible for most of the Extreme Gear products Robotnik Corp. made in the last game except for Blue Star and Red Rock which were redesigned by Tails. (The Yellow Tail built anew from the ground up.) It could be a front by Dr. Eggman or that Robotnik Corp. and all its licensed Extreme Gear were sold or they simply continue production where Robotnik Corp. finished. Either way they now provide the character boards of the game.

Accelovice
Debuting in Sonic Free Riders, they created the Extreme Gears for the Xbox Live Avatar as well as a few other major boards and perhaps the new design or line of Extreme Gears. While the name is similar to Accevive Corp and claimed the creation of its boards, it is unconfirmed if it's the same business under a new company name.

Competitive racing
The World Grand Prix is a competition for Extreme Gear racers around the world to compete with each other to see who is the fastest with riding on Extreme Gear by completing a series of race courses.