Over the next two years Speed released a string of singles, all of which charted in the top two positions, and three more albums (including the compilation Moment), all of which topped the charts and cemented the group's position as one of the most commercially important groups of their era. Their sound also progressed in a more R&B orientated direction, following the standard Japanese pop industry procedure of developing a group's sound in a more mature and sophisticated direction in accordance with the tastes of they young fans as they grow up.
In 1999, the four members of Speed all released solo material, mostly as standalone singles, although Eriko's "Everyday Be with You" was appended as a B-Side to Speed's "Breakin' Out the Morning." Then, in the autumn of 1999, the members announced that they would be disbanding, and by the end of March the following year the band had ceased all activity together. Hitoe left for the United States to attend art school; Takako's solo career was quickly overshadowed by her far more successful modeling work; Hiroko, under her nickname Hiro, had the most successful musical career outside the confines of the group, albeit one with steadily declining chart positions over time. Eriko had the most eclectic and troubled post-Speed career, appearing on-stage in a number of musical productions while her solo career ricocheted around a number of genres without ever really taking off, before becoming embroiled in a brief scandal following her sudden pregnancy and marriage in 2004. The breakup, however, was not permanent and the group reunited on two occasions for charity concerts, becoming ambassadors for Save the Children, and releasing a handful of one-off singles. In addition, while the group was officially disbanded it is notable that the members all shifted their allegiance from original label Toy's Factory to Avex Trax. They appeared together for a televised reunion in 1998 and their official reunion was announced soon after, with the single "Ashita no Sora" following in November of that year. ~ Ian Martin, Rovi