Last week I switched my wheels and tires out from OEM 15 x 6 wheels with 195/55R15 Good Year Fuel Max tires to 16 x 7 Drag DR9 wheels (16.55 lbs.) with 205/50R16 Good Year Fuel Max tires. ( I wanted a different look) At first I didn't notice any change in mpg's, but that soon changed. The temps went down into the 20's for lows and 30's for highs. I went from 48 - 50 mpg to 41 -43 mpg in just a few days. I assumed that the drop was due to the cold weather. This morning I decided to check the tire pressure in the new tires. 32 psi all the way around. I asked the guys that installed the tires to fill them up to 44 front, 42 rear. I guess that never happened. Anyway, I looked on the sidewall of the tire to check max pressure and I was shocked (51 psi). I ran 44 front, 42 front on my old set, because that was what I was advised to do by our members. Should I run 51 front, 49 rear on this set? Any thoughts? Also, I did block the lower grill 100% today.
I adjust mine to get even tire wear, always staying below the max printed on the tire. Better MPG but wearing out the tire sooner is a false economy.
At such low temps I would not suggest going too high unless your roads are very smooth and you generally travel at lower speeds. At temps below 45F your all-season tires become less pliable and they do not grip road irregularities as well as they do in warmer temps. This reduces grip and can actually cause a loss of mpg due to the tires skipping across those parts of the road and reducing forward momentum. It could also increased stopping distance. I would try running them at your usual 44/42psi for now and see how things go. The mpg increase from 44psi to 51psi would be very small anyway. Why risk yourself, others and your comfort for such a small gain? Here is a visual of what happens to all-season or summer tires in cold temps.
The manufacturer selects the air pressure the gives their desired handling and ride characteristics. The heavier end of the car usually, but not always, gets a little higher pressure.
I have run 49 front 47 rear since Oct 2010. I have close to 100,000 miles on the car. Average MPG is 55. In the winter it drops because of differnt gas and my remote start.
Thanks Judgeless... How much does it drop in winter? I'm new to this and want some sort of baseline comparison.
Depends on your location and commute type. I lose 5+mpg and I live in a pretty mild climate. The more rain and freezing temps you have to deal with the worse the hit. In short you have to deal with: Winter fuel Longer warm up times Dense air is colder thus increasing aerodynamic drag Tire rolling resistance goes up in cold temps Rain/water on the road dramatically increases rolling resistance Heater/AC use (exessive) dramatically reduces mpg Time spent idling to warm up car and/or defrost windows More time spent idling trying to keep the engine and emissions system hot For more check this thread. Why mileage gets worse in winter | PriusChat
I was worried about that. My wife took my car out tonight. My mpg's are way off now, thanks hun!!! LOL!!! It really is like a video game. I'm a 43 yr old teenager still playing pac man. My new years resolution is to get into the 600+ club.
