[Big Dave]

My rule of thumb is to drive the posted limit. Driving 20 under will get you pulled over and searched for drugs or somebody will throw a chair at you. (In Indiana everyone thinks they are Bobby Knight). Funny thing, at the posted limit (55 or 60 on rural roads 70 on the slab) I'm still passing 40% of the traffic.

There are people driving way too slow. Taken to its logical extreme slowing downto the max means stopping. At zero MPH, you aren't burning any fuel at all. That's why I latch onto the limit. Driving that speed cannot be logically attacked from either side.

P&G doesn't work well for me so I only do it occasionally when I can't see anything in the mirrors. Wild speed variuations in traffic is rude IMO. Coasting down to a stop sign or a light from a mile off at the limit is just good safe driving, however.

I have Firestone tires. You cannot over-inflate them, despite what the canadian meathead says. At 105 psi the tread doesn't even crown.