Multi-mode auxiliary wheel system adapted for rolling a folded bike, comprising: an upper frame member, at least one supporting side frame member attached to the upper frame member and adapted for attachment to the foldable bike so that the upper frame member is positioned adjacent an upper portion of the rear wheel during an unfolded, ridable, condition of the bike, but adjacent a lower portion of the rear wheel and the ground during a folded, non-ridable, condition of the bike. Lateral and transverse attachment, detachment, and displacement, of the axle, whether horizontal pivotable displacement or not, are provided for with an axle member with auxiliary wheels thereon such that, together with a swivel caster auxiliary wheel, the system enables a user to wheel the bike when in a folded condition, in either a luggage cart type auxiliary wheeling mode or a shopping cart type wheeling mode.