Radio BMX Raceline Helium BMX Race Frame - Pro XL 21.25'' TT Black. Tested on the track and designed in conjunction with a team with BMX race knowledge spanning 3 decades Radio Raceline Helium frames are well thought out and powerful pure bred race machines. You'll find no gimmicks no "goofy" tubing shapes or unnecessary features. These frames have been built from the ground up with race proven geometry and technology combined with clean functional aesthetics designed to give you the holeshot out of the gate. Radio Raceline Helium frames are designed to feel comfortable stiff and fast exactly how a race bike should.