Polo Bikes

rolling resistance is even more experimental stuff than friction, i don't know enough about it to really beeing able to explain everything right. main thing is: rolling resistance increases exponentially as pressure gets lower. probably because: if you have lower tire pressure, your tire doesn't just roll in clean contact to the ground, but it gets warped constantly. this needs energy, which is then mostly transfered into heat.

hope my poor technical english ins't too confusing

Great explanation. I remember reading somewhere that wider profile tyres (assuming same tyre pressure) have lower rolling resistance (although obviously wider profile equals great aerodyamic resistance), but this clearly isn't something that would come into polo.