[arcwhite]

YT's skateboard introduces the telescopic contact smartwheels pretty early on as a Courier essential.

I don't recall Hiro's motorcycle being much a part of the story, it might also have had the smartwheels but isn't discussed until later...

[calmbonsai]

Yep. His motorcycle is introduced in great detail and then afterwards Stephenson deliberately trolls us with "...after that, it's just a chase scene" and it's never mentioned again. ;)