Quote:
Originally Posted by wobombat
(Tire pressure quote)
How does this work? The more pressure in the tires, the less tire on the road, right?
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(Originally edited on 2013-April-06. Edited again on 2013-September-18: Take the unedited sections of this post with a grain of salt. I think perhaps the van will accelerate faster at a lower tire pressure, But again it'll coast longer too once at a given speed. So, Where does that put a good tire pressure? The one that gives the highest FE and lasts the longest?)
Correct, But I think you should have most of the tire contacting the road at a given time so the tread wears evenly and for other reasons; I did some comparison tests today between 55, 50 and 45 PSI and the car could accelerate quicker at a given engine LOD when at 45 PSI than at 50 or 55 PSI, Thus it allows you to accelerate at the same rate as a higher pressure at a lower engine load which = Higher fuel economy (In theory.)
After you get the ScanGaugeII, You can try comparing tire pressures. See how fast your car accelerates to a given speed at a LOD of 17 or so with 55 PSI compared to 50 PSI and 45 PSI and perhaps even 40 PSI.
(Edit: This next paragraph was taking the SG2 reading for granted when it wasn't calibrated very well.)
Perhaps I'm not thinking of this quite right but I know for one trip I averaged over 38 MPG in Moony with a tire strapped to the roof and very mild pulse and gliding (Without turning the engine off) when the PSI was 45ish and I didn't manage that on a recent trip without the tire strapped on or with roof racks, With an oil change and pizza pans with the tires set at 55ish and heavy load pulse and gliding.
Also, This specific paragraph is a bit off-topic but using the tire pressure pumps at gas stations to deflate the tires may take a lot more time than deflating the tires a bit lower than the PSI you're aiming for with a paper clip and re-inflating them.