Hi-Speed Shoes

Soap shoes were featured in the video game Sonic Adventure 2. This game presented many billboards, blimps, and benches advertising the shoes; Sonic also wore a custom version of the Scorcher/Nitro shoe exclusive to the title, while the darker character Shadow wore hybrid jet hoverskate/grind shoes, as grinding (or "soaping") debuted as an important new gameplay element. Grinding remains a core element in recent Sonic games, though officially licensed Soap shoes have given way to generic grind shoes. Pending the sale of Soap to In-Stride and later HSL, no actions were taken for the continuation of the partnership.

However, in two episodes of the anime Sonic X, Sonic's Soap shoes are brought in to give him an advantage over his enemies.

Actual footwear
Soap Shoes are shoes made for grinding. They were introduced by Chris Morris of Artemis Innovations Inc. with the brand name "Soap" in 1997. They have a plastic concavity in the sole, which allows the wearer to grind on objects such as pipes, handrails, and stone ledges. The company and their product rapidly gained popularity through fansites, a video game, and live demonstrations. Soap fell to legal vulnerabilities and was readministrated twice, eventually bringing the brand to Heeling Sports Limited. The act of grinding on rails and ledges specifically using Soap shoes has been dubbed "soaping," with the "soaper" being the one performing said act.

Videos
350px|Real grinding action.

Trivia

 * Though Sonic's Soap Shoes still appear in the HD version of Sonic Adventure 2, the Soap Shoe ads are not present, having been replaced with other ads, such as ads for Sonic Team or the word "Speed".
 * A pair of Sonic's Soap Shoes, dubbed as "Sonic 2G Shoes" can be unlocked for an Xbox Avatar by amassing a total playtime of 10 hours in Sonic Adventure 2. The shoes, however, are not as detailed as their in-game counterpart.
 * Interestingly enough, the brand has two shoes named CHAOS_6028 and CHAOS_6029. Whether this is a reference to the Sonic series is not known.
 * The "soapshoes.com" website, as mentioned above, links to a "Directory Listing Denied" error.