I rode my bike into work Saturday morning and back this morning. It works out perfect it is 15 miles or 25ish kms each way. My plan in a can is to ride at a cadence of 90-100 RPMs comfortably and move up a gear each week or so therefore bringing up my speed. Right now my average speed being 13mph/20kmp but keep in mind I am going for cadence not speed. I also throw in sprints every once and a while. I still haven't got road tires so I am riding on knobbies, so as I stop pedaling my bike slows considerably.