Tire PSI

47 isn't that bad...
It got cold here and I'm lucky if I hit 40 right now.

 

Teens degree f weather! getting only 47? You are doing really good. If you have any hills I would think less mpg, using heat also makes a diffrence. Just enjoy your car. When you get around 10k to 15k miles on your car you will see a small increase in mpg as things loosen up on the car and you learn the car better. You will see 50+ next summer.

 

I have 4 coffee friends and in teens degrees temps,
1. 47mpg 2. 39mpg 3. 42 mpg 4. 44mpg as of today. Thats one 2011 and three 2012's.

Enjoy!

 

I have mine set at 42F and 40R fr both my 15s (winter) and 17s (summer). Ride is stiffer but the MPGs are optimal

 

42 psi front/40 psi rear I found best is for wear, stability and mpg. Go 40/38 if you are sensitive to road vibration or your lady needs to put on make-up while you drive.

 

I went to 42f 40r on my winters the other day and it's intolerable on most of Dublins wonderful roads!

I'm going back to 40 / 38 for a slightly softer ride...I'll suffer the mpg loss for some comfort

 

I'd be checking those figures again somewhere else, that's too much of a difference in a week, even considering the cold

 

How cold was it when you checked them at 42PSI? According to Tire Rack, every 10F changes the PSI by 1. Some tires just don't seem to hold air that great, either. Were they all the same, or did you just check one?

 

Oh for Pete's sake you just want to see if I can find my previously posted graph.
This is generic, using some rolling resistance equations given in a prior thread.
Focus on the shape of the curve, the MPG drop off is 2x as bad under 35 psi.
Unrelated to psig, keep in mind rolling resistance is higher when tire is colder.
Takes the tires about 20-minutes to warm up.

 

My new snow tires have a max inflation of 44 psi. I would think setting the cold psi to 40/38 would be ok, allow room for heat up

 

That max inflation label typically is a cold pressure, and already includes margin for heating up.

 

I went to from 35 f/r to 42f/40r a week ago and gained about 15% on my average MPG. That's a win in my book. The ride is a bit harsher, but worth it.

SCH-I605 ?

 

I think mid 40s should be a good average MPG. I set mine to 45 all around and I get 47mpg mostly on freeway. Now I get 44 MPG most likely to winter blend.