The fat outer tire can be moved in and out on the axle before the race to achieve maximum cornering power for track conditions.

FORBES: Vroom!

Pre-race favourite Kramer, 23, appeared unaware of his transgression, which came mid-race when his skate crossed the dividing line as he transferred from the outer to inner lanes.

BBC: Sven Kramer mistake hands 10,000m gold to Korea's Lee