Excuse my lack of knowledge of physics but how come a bikes front wheel goes round on a set of rollers? I know it sits on a roller with bearings but what force moves the wheel round when the bike is stationary. If the rear roller did not roll then I could understand that this would transfer to forward movement,(like as if the bike was on the ground and therefore the front wheel would start to turn).

Odd question I know…

Look at the drive belt.

Oh I see, they have a belt/other drive bringing them together? That makes sense! I genuinely did not know this, and knew magic does not really exist. Thanks crikey I can stop scratching my head now.