Bike maintenance

I’ve been noticing that the ride to and from work has been becoming more and more effort. At first I thought it was just that I am getting slacker in my old age or something, but tonight on the way home I noticed that the rear tire was looking a little squooshed when I sat on the bike. I therefore gave in and performed some basic bike maintenance tonight — removed the 5mm of mud from the frame (pretty good given it hasn’t rained here in months), the general layer of dirt and grime on everything, and the grease buildup I get on the rear wheel which I assume is caused by the grease from the rear hub). I checked the tire pressure as well… It was a third of what it should have been, so hopefully I am staring down the barrel of a much lower rolling resistance.