.. When your tyres are pumped up.
..... And when your seat is high enough.
Its probably also easier when your lungs don't shrink when it gets cold, when you don't have a stodgy pudding at lunch and when you have done more exercise in teh last three months than I have!
But I knocked three minutes off my time this morning and only got off for twenty yards on the way home! Woo haaa.....