This weekend I got a very dramatic lesson in how tire pressure affects gas mileage - from my bicycle.
Abelisto and I usually ride our bikes to the Farmer's Market in Winona on Saturday mornings. We have panniers on our bikes that can hold the equivalent of 2 brown paper grocery bags each. Together we can get over a week's groceries in the panniers.
Anyway, over the last couple weeks I had been having more and more trouble riding the bike. I was cursing poor Adventure Cycle, thinking that they were at fault (had a recent tune up and one of the problems following it was this difficulty/trouble with riding - the other problem, erratic shifting issues still is going on). On Saturday morning Abelisto noticed that my rear tire was extremely low on air. We quickly went to the service station and added quite a bit of air pressure to both my tires.
Getting back on the bike was amazing - it now rolled so freely, so effortlessly... The difference in energy expenditure was unbelievable. It must be much the same with a car, except we do not notice it since we aren't doing the pedaling...
Now I have got to check the tires on all the vehicles in the household.
Now I need to check the tire pressures on all the vehicles.