Don't forget...other people check your tire pressure too
 

I couldn't figure out why my FE was dropping. I couldn't figure out why P&G seemed more difficult...I thought I had less patience or the cooler air is denser or something. Now I know.

I don't check my tires often. Because I run maximum pressure, it's not a safety issue if they lose a few pounds; and anyway, I rarely have a leak, even a slow one. So, imagine my surprise when I checked tires on both vehicles yesterday and found them far lower than maximum. The VW's tires were down to exactly the number suggested by VW, and the GMC's tires were down to exactly 65 all around (vs. 80 front, 72 rear).

If I had leaky tires I would expect one tire to be at full pressure and a couple tires to be randomly lower...not four equal tires. Finally I realized what happened -- when I got the oil changed in the VW, they adjusted my tire pressure (thanks a lot!), and when my truck was serviced...same thing.

So, remember folks...even if you don't check your tires often, check them after a mechanic or other person has driven/adjusted/serviced your vehicle.

Now I won't know if the new lower-viscosity oil I put in is the cause of any potential (re-)gain, or if it's the tire pressure...

or request your mechanic set your tires to a certain pressure

i work as a mechanic myself, even though i run 50psi in tires rated for 35 in my personal daily driver, usually i set tire pressures to the recommended specs on customer vehicles. the exception would be if atleast 3 are at max pressure or higher, then i'll set or reduce them to max pressure. sending them out over inflated would be a liability issue.

that said, i think most any shop will set tire pressure to whatever you request. even better, making the request at whatever psi might insure a lazy oil changer doesnt skip checking your tires.

Filled my tires up to 40psi, and noticed a pretty good gain in MPG....Will check them regularly at cooler times during the morning/afternoon.

This afternoon I aired my tires to 45 PSI cold. I normally inflate the tires to 40 hot. I noticed a bit more road noise than normal. I don't know if I'm going to keep them this high.

-Jay

I once asked a gasoline station attendant (here in Japan many places are still full service) if I could use their air. He said that he would do it for me. I said, no thanks, that I could handle it. I go back to my car to get my wallet to pay, setting down the air canister, and as I got out of the car he was LETTING OUT AIR. I was like, "what the heck are you doing?!" His response was that I had overfilled the tires. Good job reading the inside of the door jam idiot. Yeah, he had no idea why tire pressures are set how they are. I gave him a quick 15 second lesson of FE. I am pretty sure that he tried to avoid servicing me any time after that... haha.

I'm definitely gliding further in the truck. Haven't driven the car.

Yup, I don't begrudge them for doing it...it's my own fault for not checking it. I'm the one doing something weird here, after all, not them. Liability is a HUGE concern for mechanics and other auto service businesses, more so with tires.

That reminds me, I was thinking I should put a sticker on my door jamb right next to the OEM one, so that others would know my preferred pressure.

I worked as a tire guy for a few years part time in high school and first years of college, and I would only change the tire pressures if they were above the rated pressure for the tire, below the OEM standard, or one was quite different from the others. Oh and on Explorers and the like I'd never put in the OEM 26 psi. It was always at least 30. 26 is ridiculous.