Max psi = 3-5 mpg

[Bjaardker]

After owning the car about a month I decided it was time to up the ante.

The first month of owning the car we were able to average about 50.9 MPG, not bad and much better than I was expecting.

I wanted to see if tire PSI made as much of a difference on the I2 as it did on the I1 so the next time we stopped for gas I inflated the tires to the max PSI listed on the sidewall.
When we got out on the road again the extra PSI was noticeable, but didn't drastically affect road feel and stiffness like it does on the I1.

Since then we have been able to get 54-55 MPG consistantly. On the next fill up I was able to get an 80 mile trip at 63.3MPG.

Moral of the story: pump it up!

[CobaltDragon]

Yes, you are likely to improve MPG...but, you are also potentially causing uneven tire wear leading to needing new tires sooner (I have seen this first hand, where the center of my brother's tires wear much faster than the rest of the tire when significantly over-inflated) - and potentially less safe because the tire/road contact area changes with tire pressure, as well.

[wstander]

Well, there is a MARKED difference between the posted 33PSI and the max 44PSI....I got good result and better tire mileage by running at 42PSI instead of the 37PSI recommended for my old Prius...

I may bump to 40PSI for a week or so as a test....can always go back

I do suggest that you not change pressures whilst the tires are hot/warm from the road though............

[HybridforCollege]

Wow, 63.3 mpg?!
I don't hypermile, but I don't floor it either.
My MID screen displays 39 MPG over the last 300 miles (3rd tank of gas). And my tires are at 36 PSI. Any Tips?

[stevenvillatoro]

Bjaardker, in the interest of being scientific, what were your tire pressures BEFORE and AFTER you made the increase? Thanks for the good feedback.

[pandisal]

I think their getting higher MPG more on highway driving... I'm getting 40 to 45 MPG in shorter drive (7 to 10 miles city driving) but I'm getting 50mpg or higher when driving longer highway. Unfortunately, I'm driving more on city than highway so total average so far on my 3rd tank is 42 so far (from 36 and 39 mpg on my first and second fill up).

Originally Posted by HybridforCollege

Wow, 63.3 mpg?!
I don't hypermile, but I don't floor it either.
My MID screen displays 39 MPG over the last 300 miles (3rd tank of gas). And my tires are at 36 PSI. Any Tips?

[wstander]

Just a note: I am at 40PSI for a day; no mpg reads yet, but wow!! This car just now came ALIVE!!!

Handling in the dry twisties is now really tight and defined, roll down to stoplights is more steady and predictable, very little to no 'push' in the corners....

Starting to LOVE this car!!!!

[Cobb]

How do you manage 39? I got 43 doing 70 and leaving it idle with the ac on for my passengers.

I just start it up and drive. No warm ups or cool downs. I try to feather the throttle to keep it green taking my time to accelerate. I also ride the brake for stopping and for shorter stops upshift on the left paddle to get all the regen I can. I go the post limit except for the interstate. There, I draft and try to keep up with traffic if very crowded. If its calm, I just go the posted limit. I use crus control everywhere I can with steady traffic and keep econ mode on except for stop n go traffic. I also keep the ac on lo, high and recycle with ac on. I drive at least 40 miles with high beams on too.

Originally Posted by HybridforCollege

Wow, 63.3 mpg?!
I don't hypermile, but I don't floor it either.
My MID screen displays 39 MPG over the last 300 miles (3rd tank of gas). And my tires are at 36 PSI. Any Tips?

[arkjones]

Originally Posted by Cobb

How do you manage 39? I got 43 doing 70 and leaving it idle with the ac on for my passengers.

Cobb, I got 39 last weekend on a "vacation" (I'll use that term loosely here) in Branson, MO. The temps were 95-105 and humidity was over 60%, plus my black I2 translates to "FREAKING HOT". The streets in Branson are steep... with frequent stop and go traffic and short trips (<1mi). So combine the heat with the stop and go and it neccessitates turning ECON off -- unless you like listening to the wife and kids go on and on and on about why her car would have been a better choice.

Then came a day trip during the "vacation" to Springfield. The long hill climbs drained the battery quick, resulting in miles and miles of climbing on just the gas. Even with turning off the AC for the climbs as much as possible, I still only averaged 39mpg (the MID claimed 47.2) for the "vacation".

[academytim]

I do a lot of highway driving in my Insight as I have 30 retail stores that I travel to in the southeast. The first week I had my Insight, I drove from Birmingham, AL to Greenville, SC and back. I used no hypermiling techniques at all. Set the cruise at the speed limit or slightly higher with the A/C blasting the whole way. The highways between these locations are extremely "hilly", there is very seldom a flat stretch of highway for more then a mile or so. On this first trip I got 47mpg on the way there, and 46mpg on the way back. Those are the actual numbers obtained from refilling the tank, not the MID.

Yesterday I made this exact same trip out to South Carolina, using the exact same highways. On the way out, I again averaged 47mpg. Before I left to drive back this morning I checked the tire pressure at the gas station. All 4 tires were at 32psi. While I did not want to bump the pressure up to the limit, I did bump all of them up to 40psi, filled the tank, and proceeded onto the interstate. I could tell an immediate difference. The MID read 53mpg when I pulled into the gas station down the road from my house, and the actual fuel economy after filling the tank was 51.6mpg on the way back. Again, this was with no hypermiling techniques whatsoever. Cruise set at the limit or slightly above and the A/C blasting the whole way.

So from my experience, going from 32psi to 40psi equates to just over 5mpg improvement in overall fuel economy.