GM Volt Forum banner
21 - 23 of 23 Posts

·
Registered
Joined
·
2,968 Posts
I read years ago that using A/C adds less resistance than driving at highway speeds with the window down. That was with ICE cars. Driving in ECO mode I went about 6 Km farther before ICE came on than with out on same trip by going about 3 Kph. slower and having to pass about 6 fewer cars at slow speed. Speed limit was 90 Kph, and I usually go 4 to 5 faster than that. A/C ECO mode is really efficient. It wasn't really hot, about 5C hotter than inside so that would possibly make a difference, was always blowing cool not cold air. Don't like cold air.
 

·
Registered
Joined
·
3,482 Posts
Keep in mind 50 PSI sitting in the garage could increase 2 psi or more when traveling at high speed in the sun on a hot day. My tires have a max 51 PSI pressure rating. Exceeding that could cause a blowout. I keep mine at 40-42 PSI.
Modern tires are tested at three or more times the sidewall PSI. The sidewall PSI is the maximum cold pressure you should set them to to avoid crowning and uneven wear, but it's definitely safe to drive them. I've run 51 PSI tires at 50 PSI cold and watched the pressure climb to about 55 PSI while driving across western Kansas in 90-100F weather.

For OP's question about wear, running the tires a little higher will actually improve the overall tread life by stiffening the sidewalls. It will also help vehicle handling, again by stiffening the sidewalls. Stiffer sidewalls improve wear by reducing the flex that occurs on the contact patch and and improves handling by reducing tire related lateral sway, this making the car more predictable and planted going through turns.
 

·
Registered
Joined
·
42 Posts
I know a guy with a Honda Insight G1 that runs his tires at 90 psi, but drives no faster than 45 mph. Has been doing it for years with no blowouts. Why 90? Because, says he, there’s no increase in gas mileage above that.

Would I do it? Heck no. But he has no problems with it.
 
21 - 23 of 23 Posts
Top