Hmm... It's extremely hard to do, I spent about 1~2 hours to success it. You have to drift then jump in order to brush the wall. Then press down or you'll fall in the void (hit the border as I did at the end). The lap doesn't count.
i know two and a half other glitches. one, on the pipe battle arena, jump from the high metal mesh onto the wall. you will only kinda be over it, and you wil sorta float. the other one and a half, are with either the loop or the corkscrew on rainod road stop up top and fall onto the other. if you aim it right, you will land, and lakutu will bting you up.
L'une des compilations de glitchs les plus complets. Celui de 7:32 est la meilleure pour moi :) Mais, il te manque le RR rail glitch, et les 2 autres SC.