Today i took delivery of my Schwalbe City Jets and inner tubes so with some luck i'll be fitting them tonight when i get home. Now the thing is i really want to ride in to work tomorrow but after yesterdays quick jaunt (a couple of miles - but at a fast pace) i was knackered. Most of it was in a headwind but it shocked me how unfit i am now.... The ride in is easy enough (flat or downhill) and the prevailing wind is usually behind you but the ride home has an evil hill whatever way i go and i'm a bit concerned about biting off more than i can chew I guess a smooth tyre will be easier to ride than a knobbly one and i can always get home on a bus to do the return leg the next day.... One of my concerns is being tired and switching off to traffic, i do have a good amount of roadcraft and defensive riding skills from a Motorbike but am a little worried that it will all go to pot if i'm knackered!!